<!DOCTYPE article PUBLIC "-//NLM//DTD JATS (Z39.96) Journal Publishing DTD v1.1 20151215//EN" "JATS-journalpublishing1.dtd">
<article xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:mml="http://www.w3.org/1998/Math/MathML" dtd-version="1.1" specific-use="sps-1.9" article-type="research-article" xml:lang="pt">
  <front>
    <journal-meta>
      <journal-id journal-id-type="nlm-ta">Arq Bras Cardiol</journal-id>
      <journal-id journal-id-type="publisher-id">abc</journal-id>
      <journal-title-group>
        <journal-title>Arquivos Brasileiros de Cardiologia</journal-title>
        <abbrev-journal-title abbrev-type="publisher">Arq. Bras. Cardiol.</abbrev-journal-title>
      </journal-title-group>
      <issn pub-type="ppub">0066-782X</issn>
      <issn pub-type="epub">1678-4170</issn>
      <publisher>
        <publisher-name>Sociedade Brasileira de Cardiologia - SBC</publisher-name>
      </publisher>
    </journal-meta>
    <article-meta>
      <article-id specific-use="scielo-v3" pub-id-type="publisher-id">vTL579GQQm55cMgyGbW7Ksz</article-id>
      <article-id specific-use="scielo-v2" pub-id-type="publisher-id">S0066-782X2023000200309</article-id>
      <article-id pub-id-type="other">00309</article-id>
      <article-id pub-id-type="doi">10.36660/abc.20220294</article-id>
      <article-categories>
        <subj-group subj-group-type="heading">
          <subject>Artigo Original</subject>
        </subj-group>
      </article-categories>
      <title-group>
        <article-title>Associa&#231;&#227;o entre N&#237;vel de Big Endotelina-1 Plasm&#225;tica e a Gravidade da Doen&#231;a Arterial Coronariana em Pacientes com Infarto do Mioc&#225;rdio sem Supradesnivelamento do Segmento ST</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <name>
            <surname>Lyu</surname>
            <given-names>Si-qi</given-names>
          </name>
          <xref ref-type="aff" rid="aff2">
            <sup>1</sup>
          </xref>
          <xref ref-type="aff" rid="aff1"/>
          <xref ref-type="aff" rid="aff3"/>
          <xref ref-type="aff" rid="aff4">
            <sup>2</sup>
          </xref>
          <role>Concep&#231;&#227;o e desenho da pesquisa</role>
          <role>Obten&#231;&#227;o de dados</role>
          <role>Revis&#227;o cr&#237;tica do manuscrito quanto ao conte&#250;do intelectual importante</role>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Zhu</surname>
            <given-names>Jun</given-names>
          </name>
          <xref ref-type="aff" rid="aff2">
            <sup>1</sup>
          </xref>
          <xref ref-type="aff" rid="aff1"/>
          <xref ref-type="aff" rid="aff3"/>
          <xref ref-type="aff" rid="aff4">
            <sup>2</sup>
          </xref>
          <role>Concep&#231;&#227;o e desenho da pesquisa</role>
          <role>Obten&#231;&#227;o de financiamento</role>
          <role>Revis&#227;o cr&#237;tica do manuscrito quanto ao conte&#250;do intelectual importante</role>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Wang</surname>
            <given-names>Juan</given-names>
          </name>
          <xref ref-type="aff" rid="aff2">
            <sup>1</sup>
          </xref>
          <xref ref-type="aff" rid="aff1"/>
          <xref ref-type="aff" rid="aff3"/>
          <xref ref-type="aff" rid="aff4">
            <sup>2</sup>
          </xref>
          <role>Obten&#231;&#227;o de dados</role>
          <role>Revis&#227;o cr&#237;tica do manuscrito quanto ao conte&#250;do intelectual importante</role>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Wu</surname>
            <given-names>Shuang</given-names>
          </name>
          <xref ref-type="aff" rid="aff2">
            <sup>1</sup>
          </xref>
          <xref ref-type="aff" rid="aff1"/>
          <xref ref-type="aff" rid="aff3"/>
          <xref ref-type="aff" rid="aff4">
            <sup>2</sup>
          </xref>
          <role>Obten&#231;&#227;o de dados</role>
          <role>Revis&#227;o cr&#237;tica do manuscrito quanto ao conte&#250;do intelectual importante</role>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Zhang</surname>
            <given-names>Han</given-names>
          </name>
          <xref ref-type="aff" rid="aff2">
            <sup>1</sup>
          </xref>
          <xref ref-type="aff" rid="aff1"/>
          <xref ref-type="aff" rid="aff3"/>
          <xref ref-type="aff" rid="aff4">
            <sup>2</sup>
          </xref>
          <role>Obten&#231;&#227;o de dados</role>
          <role>Revis&#227;o cr&#237;tica do manuscrito quanto ao conte&#250;do intelectual importante</role>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Shao</surname>
            <given-names>Xing-hui</given-names>
          </name>
          <xref ref-type="aff" rid="aff2">
            <sup>1</sup>
          </xref>
          <xref ref-type="aff" rid="aff1"/>
          <xref ref-type="aff" rid="aff3"/>
          <xref ref-type="aff" rid="aff4">
            <sup>2</sup>
          </xref>
          <role>Obten&#231;&#227;o de dados</role>
          <role>Revis&#227;o cr&#237;tica do manuscrito quanto ao conte&#250;do intelectual importante</role>
        </contrib>
        <contrib contrib-type="author">
          <contrib-id contrib-id-type="orcid">0000-0001-9594-8133</contrib-id>
          <name>
            <surname>Yang</surname>
            <given-names>Yan-min</given-names>
          </name>
          <xref ref-type="aff" rid="aff2">
            <sup>1</sup>
          </xref>
          <xref ref-type="aff" rid="aff1"/>
          <xref ref-type="aff" rid="aff3"/>
          <xref ref-type="aff" rid="aff4">
            <sup>2</sup>
          </xref>
          <role>Concep&#231;&#227;o e desenho da pesquisa</role>
          <role>Obten&#231;&#227;o de financiamento</role>
          <role>Revis&#227;o cr&#237;tica do manuscrito quanto ao conte&#250;do intelectual importante</role>
        </contrib>
      </contrib-group>
      <aff id="aff1">
        <institution content-type="orgdiv1">Emergency Center</institution>
        <institution content-type="orgname">Fuwai Hospital</institution>
      </aff>
      <aff id="aff2">
        <label> 1 </label>
        <institution content-type="orgdiv2">National Center for Cardiovascular Diseases</institution>
        <institution content-type="orgdiv1">Chinese Academy of Medical Sciences</institution>
        <institution content-type="orgname">Peking Union Medical College</institution>
        <addr-line>
          <named-content content-type="city">Beijing</named-content>
        </addr-line>
        <country country="CN">China</country>
        <institution content-type="original">Emergency Center , Fuwai Hospital , National Center for Cardiovascular Diseases , Chinese Academy of Medical Sciences and Peking Union Medical College , Beijing &#8211; China </institution>
      </aff>
      <aff id="aff3">
        <institution content-type="orgdiv1">Center of Cardiovascular Diseases</institution>
        <institution content-type="orgname">Fuwai Hospital</institution>
      </aff>
      <aff id="aff4">
        <label> 2 </label>
        <institution content-type="orgdiv2">National Center for Cardiovascular Diseases</institution>
        <institution content-type="orgdiv1">Chinese Academy of Medical Sciences</institution>
        <institution content-type="orgname">Peking Union Medical College</institution>
        <addr-line>
          <named-content content-type="city">Beijing</named-content>
        </addr-line>
        <country country="CN">China</country>
        <institution content-type="original">National Clinical Research Center of Cardiovascular Diseases , Fuwai Hospital , National Center for Cardiovascular Diseases , Chinese Academy of Medical Sciences and Peking Union Medical College , Beijing &#8211; China </institution>
      </aff>
      <author-notes>
        <corresp id="c01">Correspond&#234;ncia: Yan-min Yang &#8226; Emergency Center, Fuwai Hospital &#8211; No. 167 Beilishi Road, Xicheng District Beijing 100037 E-mail: <email>yymfuwai@163.com</email> </corresp>
        <fn fn-type="conflict">
          <p>Potencial conflito de interesse</p>
          <p>N&#227;o h&#225; conflito com o presente artigo</p>
        </fn>
      </author-notes>
      <pub-date date-type="pub" publication-format="electronic">
        <day>06</day>
        <month>03</month>
        <year>2023</year>
      </pub-date>
      <pub-date date-type="collection" publication-format="electronic">
        <month>02</month>
        <year>2023</year>
      </pub-date>
      <volume>120</volume>
      <issue>2</issue>
      <elocation-id>e20220294</elocation-id>
      <history>
        <date date-type="received">
          <day>02</day>
          <month>08</month>
          <year>2021</year>
        </date>
        <date date-type="rev-recd">
          <day>28</day>
          <month>09</month>
          <year>2022</year>
        </date>
        <date date-type="accepted">
          <day>19</day>
          <month>10</month>
          <year>2022</year>
        </date>
      </history>
      <permissions>
        <license license-type="open-access" xlink:href="https://creativecommons.org/licenses/by/4.0/" xml:lang="en">
          <license-p>This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.</license-p>
        </license>
      </permissions>
      <abstract>
        <title>Resumo</title>
        <sec>
          <title>Fundamento</title>
          <p>A estratifica&#231;&#227;o de risco precoce com biomarcadores simples &#233; essencial em pacientes com infarto do mioc&#225;rdio sem supradesnivelamento do segmento ST (IAMSSST).</p>
        </sec>
        <sec>
          <title>Objetivo</title>
          <p>Este estudo tem o objetivo de avaliar a associa&#231;&#227;o entre n&#237;vel de big endotelina-1 plasm&#225;tica (ET-1) e o escore SYNTAX (SS) em pacientes com IAMSSST.</p>
        </sec>
        <sec>
          <title>M&#233;todos</title>
          <p>Foram recrutados 766 pacientes com IAMSSST que passaram por angiografia coron&#225;ria. Os pacientes foram divididos em tr&#234;s grupos: SS baixo (&#8804;22), SS intermedi&#225;rio (23-32), e SS alto (&gt;32). A correla&#231;&#227;o de Spearman, o ajuste de curva suave, a regress&#227;o log&#237;stica, e a an&#225;lise de curva caracter&#237;stica de opera&#231;&#227;o do receptor (ROC) foram realizados para avaliar a associa&#231;&#227;o entre o n&#237;vel de big ET-1 plasm&#225;tica e o SS. Um p-valor &lt;0.05 foi considerado estatisticamente significativo.</p>
        </sec>
        <sec>
          <title>Resultados</title>
          <p>Foi identificada uma correla&#231;&#227;o significativa entre a big ET-1 e o SS (r=0,378, p&lt;0,001). A curva suavizada indicou uma correla&#231;&#227;o positiva entre o n&#237;vel de big ET-1 plasm&#225;tica e o SS. A an&#225;lise de curva ROC demonstrou que a &#225;rea sob a curva foi de 0,695 (0,661-0,727) e o ponto de corte ideal do n&#237;vel de big ET-1 plasm&#225;tica foi de 0,35 pmol/l. A regress&#227;o log&#237;stica demonstrou que a big ET-1 elevada era um preditor independente de SS intermedi&#225;rio a alto em pacientes com IAMSSST, seja como vari&#225;vel cont&#237;nua [RC (IC 95%: 1,110 (1,053-1,170), p&lt;0,001] ou como vari&#225;vel categ&#243;rica [RC (IC 95%: 2,962 (2,073-4,233), p&lt;0,001].</p>
        </sec>
        <sec>
          <title>Conclus&#227;o</title>
          <p>Em pacientes com IAMSSST, o n&#237;vel de big ET-1 plasm&#225;tica estava significativamente correlacionado ao SS. O n&#237;vel de big ET-1 plasm&#225;tica elevado foi um preditor independente para SS intermedi&#225;rio a alto.</p>
        </sec>
      </abstract>
      <kwd-group xml:lang="pt">
        <kwd>Doen&#231;a Arterial Coronariana</kwd>
        <kwd>Infarto do Mioc&#225;rdio sem Supradesnivelamento do Segmento ST</kwd>
        <kwd>Endotelina-1</kwd>
      </kwd-group>
      <funding-group>
        <award-group>
          <funding-source>National Key Research and Develop Program of China</funding-source>
          <award-id>2017YFC0908802</award-id>
        </award-group>
        <funding-statement>Fontes de financiamento: O presente estudo foi financiado por National Key Research and Develop Program of China (number 2017YFC0908802).</funding-statement>
      </funding-group>
      <counts>
        <fig-count count="6"/>
        <table-count count="4"/>
        <equation-count count="0"/>
        <ref-count count="38"/>
      </counts>
    </article-meta>
  </front>
  <body>
    <sec sec-type="intro">
      <title>Introdu&#231;&#227;o</title>
      <p>Como uma das principais causas de mortalidade em todo o mundo, o infarto do mioc&#225;rdio est&#225; associado a graves amea&#231;as &#224; sa&#250;de p&#250;blica e despesas m&#233;dicas altas. <sup><xref rid="B1" ref-type="bibr">1</xref> , <xref rid="B2" ref-type="bibr">2</xref> </sup> Apesar de not&#225;veis avan&#231;os em preven&#231;&#227;o e tratamento, a morbidade e a mortalidade de infarto do mioc&#225;rdio sem supradesnivelamento do segmento ST (IAMSSST) continuam alta, especialmente nos pa&#237;ses em desenvolvimento. <sup><xref rid="B1" ref-type="bibr">1</xref> , <xref rid="B2" ref-type="bibr">2</xref> </sup> A estratifica&#231;&#227;o de risco precoce &#233; essencial para orientar o tratamento. <sup><xref rid="B1" ref-type="bibr">1</xref> , <xref rid="B2" ref-type="bibr">2</xref> </sup> A angiografia coron&#225;ria apresenta informa&#231;&#245;es importantes sobre a morfologia, a gravidade e a carga ateroscler&#243;tica, que t&#234;m sido apontadas como associadas ao progn&#243;stico de curto e longo prazo de pacientes com IAMSSST. <sup><xref rid="B3" ref-type="bibr">3</xref></sup> O escore SYNTAX ( <italic>SYNergy between PCI with TAXUS&#8482; and Cardiac Surgery</italic> ) (SS), um esquema de pontua&#231;&#227;o angiogr&#225;fica detalhado baseado na anatomia coron&#225;ria e nas caracter&#237;sticas da les&#227;o, &#233; recomendado para quantificar a gravidade da doen&#231;a arterial coronariana e determinar a terapia de reperfus&#227;o adequada para pacientes com IAMSSST. <sup><xref rid="B3" ref-type="bibr">3</xref> - <xref rid="B6" ref-type="bibr">6</xref> </sup> A identifica&#231;&#227;o de pacientes com alto risco de carga ateroscler&#243;tica pesada e progn&#243;stico adverso com testes simples e convenientes &#233; crucial na implementa&#231;&#227;o de cuidados intensivos oportunos e na ado&#231;&#227;o de estrat&#233;gia de controle ideal, que tem sido indicada para reduzir a morbidade e mortalidade de IAMSSST. <sup><xref rid="B1" ref-type="bibr">1</xref> , <xref rid="B2" ref-type="bibr">2</xref> </sup> </p>
      <p>A endotelina-1 (ET-1), pept&#237;deo derivado de c&#233;lulas endoteliais, tem sido indicada como associada &#224; disfun&#231;&#227;o endotelial, inflama&#231;&#227;o e remodela&#231;&#227;o mioc&#225;rdica, que participam do agravamento da aterosclerose. <sup><xref rid="B7" ref-type="bibr">7</xref> - <xref rid="B9" ref-type="bibr">9</xref> </sup> Foi detectado que a ET-1 &#233; elevada no curso de infarto agudo do mioc&#225;rdio (IAM). <sup><xref rid="B8" ref-type="bibr">8</xref></sup> Entretanto, devido &#224; alta atividade biol&#243;gica e meia-vida curta, a ET-1 &#233; rapidamente eliminada na vasculatura pulmonar e seu n&#237;vel na circula&#231;&#227;o perif&#233;rica &#233; geralmente subestimado, <sup><xref rid="B7" ref-type="bibr">7</xref> , <xref rid="B8" ref-type="bibr">8</xref> </sup> A big ET-1 &#233; a precursora da ET-1 sem fun&#231;&#227;o biol&#243;gica, mas com meia-vida mais longa na circula&#231;&#227;o perif&#233;rica. Em ambientes cl&#237;nicos, a big ET-1 &#233; mais facilmente medida e amplamente utilizada para avaliar a atividade do sistema endotelial. <sup><xref rid="B7" ref-type="bibr">7</xref> , <xref rid="B8" ref-type="bibr">8</xref> </sup> V&#225;rios estudos demonstraram que o n&#237;vel elevado de big ET-1 &#233; um fator de risco para progn&#243;stico adverso em pacientes com insufici&#234;ncia card&#237;aca, <sup><xref rid="B10" ref-type="bibr">10</xref></sup> doen&#231;a arterial coronariana (DAC), <sup><xref rid="B11" ref-type="bibr">11</xref> - <xref rid="B15" ref-type="bibr">15</xref> </sup> e cardiomiopatia hipertr&#243;fica. <sup><xref rid="B16" ref-type="bibr">16</xref></sup> No entanto, a associa&#231;&#227;o entre o n&#237;vel de big ET-1 plasm&#225;tica e a gravidade da DAC em pacientes com IAMSSST n&#227;o foi avaliada anteriormente. Portanto, realizamos um estudo transversal para avaliar a rela&#231;&#227;o do n&#237;vel de big ET-1 plasm&#225;tica com o escore SYNTAX em pacientes chineses com IAMSSST.</p>
    </sec>
    <sec sec-type="methods">
      <title>M&#233;todos</title>
      <sec>
        <title>Popula&#231;&#227;o do estudo</title>
        <p>Este estudo recrutou consecutivamente pacientes com IAMSSST submetidos a angiografia coron&#225;ria no departamento de emerg&#234;ncia do Hospital Fuwai de julho de 2017 a junho de 2018. O IAMSSST foi definido como o IAM sem supradesnivelamento do segmento ST persistente. <sup><xref rid="B1" ref-type="bibr">1</xref> , <xref rid="B2" ref-type="bibr">2</xref> </sup> O diagn&#243;stico de IAM foi verificado de acordo com a Defini&#231;&#227;o universal de infarto do mioc&#225;rdio. <sup><xref rid="B17" ref-type="bibr">17</xref></sup> Os crit&#233;rios de exclus&#227;o inclu&#237;ram: hist&#243;ria de interven&#231;&#227;o coron&#225;ria percut&#226;nea (ICP) ou enxerto de bypass na art&#233;ria coron&#225;ria (CABG), insufici&#234;ncia hep&#225;tica e renal grave, infec&#231;&#227;o ativa, doen&#231;as inflamat&#243;rias sist&#234;micas e malignidade. O estudo foi aprovado pelo comit&#234; de &#233;tica do Hospital Fuwai e em conformidade com a Declara&#231;&#227;o de Helsinki. Todos os pacientes assinaram o consentimento informado para participarem.</p>
      </sec>
      <sec>
        <title>Linha de base</title>
        <p>Os dados cl&#237;nicos demogr&#225;ficos, hist&#243;ricos m&#233;dicos, exames f&#237;sicos, exames laboratoriais, exames de imagem e regimes terap&#234;uticos foram obtidos por meio de entrevistas com os pacientes, consulta a seus m&#233;dicos e an&#225;lise de prontu&#225;rios m&#233;dicos. Foram coletadas amostras de sangue venoso de todos os pacientes na admiss&#227;o antes da angiografia coron&#225;ria. O n&#237;vel de big ET-1 plasm&#225;tica foi medido usando um imunoensaio enzim&#225;tico comercial altamente sens&#237;vel e espec&#237;fico (BI-20082H, Biomedica, Wien, &#193;ustria). O clearance de creatinina foi calculado usando-se a f&#243;rmula de Cockcroft-Gault. A angiografia coron&#225;ria quantitativa foi realizada em m&#250;ltiplos cortes ortogonais com t&#233;cnicas padr&#227;o. O escore SYNTAX foi calculado usando-se uma calculadora online dedicada (http://syntaxscore.org/calculator/start.htm) baseado nos crit&#233;rios de pontua&#231;&#227;o relatados anteriormente. <sup><xref rid="B4" ref-type="bibr">4</xref></sup> Todos as angiografias coron&#225;rias foram avaliadas independentemente por dois cardiologistas experientes, cegos para os dados cl&#237;nicos, apesar de qualquer discord&#226;ncia ser resolvida por consenso. De acordo com os resultados do estudo SYNTAX, a popula&#231;&#227;o do estudo foi dividida em tr&#234;s grupos: SS baixo (SS&#8804;22), SS intermedi&#225;rio (23-32) e SS alto (SS&gt;32). <sup><xref rid="B6" ref-type="bibr">6</xref></sup> </p>
      </sec>
      <sec>
        <title>An&#225;lise estat&#237;stica</title>
        <p>As vari&#225;veis cont&#237;nuas s&#227;o apresentadas como medianas (faixas interquartis) e comparadas pelos testes de Kruskal-Wallis, pois os dados n&#227;o apresentaram distribui&#231;&#227;o normal segundo os testes de Kolmogorov&#8211;Smirnov. Vari&#225;veis categ&#243;ricas s&#227;o apresentadas como porcentagens e comparadas pelo teste &#967;2 de Pearson ou teste exato de Fisher. Para compara&#231;&#245;es m&#250;ltiplas, a corre&#231;&#227;o de Bonferroni foi utilizada para ajustar o n&#237;vel de signific&#226;ncia. A rela&#231;&#227;o entre o n&#237;vel de big ET-1 plasm&#225;tica e SS foi avaliada usando a an&#225;lise de correla&#231;&#227;o de Spearman. O ajuste de curva suave padronizado para poss&#237;veis fatores de confus&#227;o foi realizado para analisar a rela&#231;&#227;o entre o n&#237;vel de big ET-1 plasm&#225;tica e o SS. A curva caracter&#237;stica de opera&#231;&#227;o do receptor (ROC) foi constru&#237;da para avaliar a capacidade preditiva do n&#237;vel de big ET-1 plasm&#225;tica para identificar SS intermedi&#225;rio a alto. O valor de corte &#243;timo do n&#237;vel de big ET-1 plasm&#225;tica para prever o SS intermedi&#225;rio a alto foi identificado como o ponto com o &#237;ndice de Youden mais alto (Sensibilidade+Especificidade-1) na curva ROC. Regress&#245;es log&#237;sticas univariadas e multivariadas foram realizadas para identificar preditores independentes para SS intermedi&#225;rio a alto, enquanto raz&#245;es de chance (RC) e intervalo de confian&#231;a (IC) de 95% foram calculados. Tr&#234;s modelos multivariados consistindo em diferentes covari&#225;veis foram constru&#237;dos para avaliar a consist&#234;ncia da associa&#231;&#227;o entre o n&#237;vel de big ET-1 plasm&#225;tica e SS intermedi&#225;rio a alto. O modelo 1 foi padronizado para idade e sexo. No Modelo 2, foram inclu&#237;das vari&#225;veis com p-valor &lt;0,10 nos modelos univariados ou clinicamente relevantes com a gravidade da DAC. No Modelo 3, as vari&#225;veis citadas foram inseridas na an&#225;lise multivariada com o m&#233;todo de RV (raz&#227;o de verossimilhan&#231;a) retroativa. Foram realizadas an&#225;lises de subgrupos para avaliar a homogeneidade da associa&#231;&#227;o entre big ET-1 alta e SS intermedi&#225;rio a alto. Um p-valor &lt;0,05 bicaudal foi definido como estatisticamente significativo. Todas as an&#225;lises estat&#237;sticas foram realizadas pelo SPSS vers&#227;o 25.0 (IBM Corporation, Nova York, EUA).</p>
      </sec>
    </sec>
    <sec sec-type="results">
      <title>Resultados</title>
      <p>De julho de 2017 a junho de 2018, um total de 766 pacientes que se apresentaram ao departamento de emerg&#234;ncia com IAMSSST documentado foram recrutados neste estudo (Figura suplementar 1). Suas caracter&#237;sticas de linha de base est&#227;o resumidas na <xref rid="t1" ref-type="table">Tabela 1</xref> . Entre os 545 pacientes do sexo masculino e 221 do sexo feminino com idade mediana de 64 anos, o SS mediano foi de 15 (faixa interquartil: 8-24,5). De acordo com o SS, os pacientes foram divididos em tr&#234;s grupos: SS baixo (&#8804;22, n=531), SS intermedi&#225;rio (23-32, n=132) e SS alto (&gt;32, n=103). Em compara&#231;&#227;o com pacientes com SS baixo, os pacientes com IAMSSST com SS intermedi&#225;rio e SS alto eram mais velhos e tinham pior classe Killip, menor fra&#231;&#227;o de eje&#231;&#227;o ventricular esquerda (FEVE) e escore GRACE mais alto (todos p&lt;0,05). Pacientes com SS intermedi&#225;rio e SS alto eram mais propensos a ter hipertens&#227;o, diabetes mellitus, acidente vascular cerebral/ataque isqu&#234;mico transit&#243;rio (AIT), doen&#231;a arterial perif&#233;rica e insufici&#234;ncia renal (todos p&lt;0,05). Al&#233;m disso, eles tendiam a ter aumento da hemoglobina A1c, &#225;cido graxo livre, pept&#237;deo natriur&#233;tico tipo N-terminal pr&#243;-B (NT-proBNP), prote&#237;na C reativa de alta sensibilidade (PCR-as) e big ET-1, mas diminu&#237;ram o clearance de hemoglobina e creatinina (todos p&lt;0,05). Quanto aos tratamentos, os pacientes com SS intermedi&#225;rio e SS alto tiveram menor taxa de uso de inibidores da enzima conversora da angiotensina (IECA)/bloqueadores de receptores de angiotensina (BRA), mas maior taxa de uso de espironolactona e diur&#233;ticos (todos p&lt;0,001).</p>
      <p>
        <table-wrap id="t1">
          <label>Tabela 1</label>
          <caption>
            <title>&#8211; Caracter&#237;sticas cl&#237;nicas de pacientes com IAMSSST estratificados pelo escore SYNTAX</title>
          </caption>
          <table frame="hsides" rules="groups">
            <colgroup width="17%">
              <col/>
              <col/>
              <col/>
              <col/>
              <col/>
              <col/>
            </colgroup>
            <thead>
              <tr>
                <th align="left">Vari&#225;veis</th>
                <th>Geral (n=766)</th>
                <th>Escore SYNTAX baixo (&#8804;22, n=531)</th>
                <th>Escore SYNTAX intermedi&#225;rio (23-32, n=132)</th>
                <th>Escore SYNTAX alto (&gt;32, n=103)</th>
                <th>p-valor</th>
              </tr>
            </thead>
            <tbody>
              <tr>
                <td colspan="6">
                  <bold>Dados demogr&#225;ficos</bold>
                </td>
              </tr>
              <tr>
                <td> Idade (anos)</td>
                <td align="center">64 (56, 71)</td>
                <td align="center">63 (55, 70) <sup>bc</sup> </td>
                <td align="center">66 (60, 73) <sup>a</sup> </td>
                <td align="center">68 (61, 77) <sup>a</sup> </td>
                <td align="center">&lt;0,001</td>
              </tr>
              <tr>
                <td> Feminino, n (%)</td>
                <td align="center">221 (28,9)</td>
                <td align="center">149 (28,1)</td>
                <td align="center">35 (26,5)</td>
                <td align="center">37 (35,9)</td>
                <td align="center">0,221</td>
              </tr>
              <tr>
                <td> &#205;ndice de massa corporal (kg/m <sup>2</sup> )</td>
                <td align="center">25,7 (23,7, 27,7)</td>
                <td align="center">25,8 (23,8, 27,8)</td>
                <td align="center">25,8 (24,2, 28,0)</td>
                <td align="center">24,6 (23,2, 26,9)</td>
                <td align="center">0,057</td>
              </tr>
              <tr>
                <td> Frequ&#234;ncia card&#237;aca (bpm)</td>
                <td align="center">72 (64, 82)</td>
                <td align="center">71 (64, 81)</td>
                <td align="center">74 (66, 82)</td>
                <td align="center">75 (64, 85)</td>
                <td align="center">0,086</td>
              </tr>
              <tr>
                <td> Press&#227;o arterial sist&#243;lica (mmHg)</td>
                <td align="center">140 (124, 153)</td>
                <td align="center">140 (123, 154)</td>
                <td align="center">138 (125, 153)</td>
                <td align="center">139 (123, 152)</td>
                <td align="center">0,966</td>
              </tr>
              <tr>
                <td> Press&#227;o arterial diast&#243;lica (mmHg)</td>
                <td align="center">79 (69, 90)</td>
                <td align="center">80 (69, 90)</td>
                <td align="center">80 (70, 90)</td>
                <td align="center">77,0 (68, 88)</td>
                <td align="center">0,443</td>
              </tr>
              <tr>
                <td>
                  <bold>Classe Killip, n (%)</bold>
                </td>
                <td> </td>
                <td> </td>
                <td> </td>
                <td> </td>
                <td align="center">0,011</td>
              </tr>
              <tr>
                <td> I</td>
                <td align="center">679 (88,6)</td>
                <td align="center">485 (91,3) <sup>b</sup> </td>
                <td align="center">106 (80,3) <sup>a</sup> </td>
                <td align="center">88 (85,4)</td>
                <td> </td>
              </tr>
              <tr>
                <td> II</td>
                <td align="center">60 (7,8)</td>
                <td align="center">31 (5,8)</td>
                <td align="center">19 (14,4)</td>
                <td align="center">10 (9,7)</td>
                <td> </td>
              </tr>
              <tr>
                <td> III</td>
                <td align="center">19 (2,5)</td>
                <td align="center">10 (1,9)</td>
                <td align="center">5 (3,8)</td>
                <td align="center">4 (3,9)</td>
                <td> </td>
              </tr>
              <tr>
                <td> IV</td>
                <td align="center">8 (1,0)</td>
                <td align="center">5 (0,9)</td>
                <td align="center">2 (1,5)</td>
                <td align="center">1 (1,0)</td>
                <td> </td>
              </tr>
              <tr>
                <td> FEVE (%)</td>
                <td align="center">60 (55, 62)</td>
                <td align="center">60 (57, 63) <sup>bc</sup> </td>
                <td align="center">58 (48, 60) <sup>a</sup> </td>
                <td align="center">58 (49, 60) <sup>a</sup> </td>
                <td align="center">&lt;0,001</td>
              </tr>
              <tr>
                <td> Escore GRACE</td>
                <td align="center">113 (98, 133)</td>
                <td align="center">111 (95, 129) <sup>bc</sup> </td>
                <td align="center">122 (104, 144) <sup>a</sup> </td>
                <td align="center">124 (106, 145) <sup>a</sup> </td>
                <td align="center">&lt;0,001</td>
              </tr>
              <tr>
                <td>
                  <bold>Hist&#243;rico m&#233;dico, n (%)</bold>
                </td>
                <td> </td>
                <td> </td>
                <td> </td>
                <td> </td>
                <td> </td>
              </tr>
              <tr>
                <td> Hipertens&#227;o</td>
                <td align="center">565 (73,8)</td>
                <td align="center">373 (70,2) <sup>b</sup> </td>
                <td align="center">108 (81,8) <sup>a</sup> </td>
                <td align="center">84 (81,6)</td>
                <td align="center">0,004</td>
              </tr>
              <tr>
                <td> Hiperlipidemia</td>
                <td align="center">481 (62,8)</td>
                <td align="center">325 (61,2)</td>
                <td align="center">86 (65,2)</td>
                <td align="center">70 (68,0)</td>
                <td align="center">0,356</td>
              </tr>
              <tr>
                <td> Diabetes mellitus</td>
                <td align="center">330 (43,1)</td>
                <td align="center">200 (37,7) <sup>c</sup> </td>
                <td align="center">65 (49,2)</td>
                <td align="center">65 (63,1) <sup>a</sup> </td>
                <td align="center">&lt;0,001</td>
              </tr>
              <tr>
                <td> Insufici&#234;ncia card&#237;aca</td>
                <td align="center">88 (11,5)</td>
                <td align="center">35 (6,6) <sup>bc</sup> </td>
                <td align="center">31 (23,5) <sup>a</sup> </td>
                <td align="center">22 (21,4) <sup>a</sup> </td>
                <td align="center">&lt;0,001</td>
              </tr>
              <tr>
                <td> Acidente vascular cerebral/AIT</td>
                <td align="center">129 (16,8)</td>
                <td align="center">78 (14,7)</td>
                <td align="center">26 (19,7)</td>
                <td align="center">25 (24,3)</td>
                <td align="center">0,037</td>
              </tr>
              <tr>
                <td> Doen&#231;a arterial perif&#233;rica</td>
                <td align="center">78 (10,2)</td>
                <td align="center">40 (7,5) <sup>bc</sup> </td>
                <td align="center">22 (16,7) <sup>a</sup> </td>
                <td align="center">16 (15,5) <sup>a</sup> </td>
                <td align="center">0,001</td>
              </tr>
              <tr>
                <td> Clearance de creatinina &lt;60ml/min</td>
                <td align="center">140 (18,3)</td>
                <td align="center">76 (14,3) <sup>bc</sup> </td>
                <td align="center">31 (23,5) <sup>a</sup> </td>
                <td align="center">33 (32,0) <sup>a</sup> </td>
                <td align="center">&lt;0,001</td>
              </tr>
              <tr>
                <td> Tabagismo</td>
                <td align="center">436 (56,9)</td>
                <td align="center">310 (58,4)</td>
                <td align="center">72 (54,5)</td>
                <td align="center">54 (52,4)</td>
                <td align="center">0,446</td>
              </tr>
              <tr>
                <td colspan="6">
                  <bold>Exames laboratoriais, mediana (FIQ)</bold>
                </td>
              </tr>
              <tr>
                <td> Leuc&#243;cito (*109/l)</td>
                <td align="center">7,7 (6,4, 9,4)</td>
                <td align="center">7,6 (6,4, 9,4)</td>
                <td align="center">7,9 (6,4, 9,4)</td>
                <td align="center">7,7 (6,3, 9,5)</td>
                <td align="center">0,732</td>
              </tr>
              <tr>
                <td> Hemoglobina (g/l)</td>
                <td align="center">141 (128, 151)</td>
                <td align="center">143 (131, 153) <sup>bc</sup> </td>
                <td align="center">138 (128, 150) <sup>a</sup> </td>
                <td align="center">131 (122, 143) <sup>a</sup> </td>
                <td align="center">&lt;0,001</td>
              </tr>
              <tr>
                <td> RDW (%)</td>
                <td align="center">12,6 (12,1, 13,1)</td>
                <td align="center">12,6 (12,1, 13,0)</td>
                <td align="center">12,6 (12,2, 13,1)</td>
                <td align="center">12,7 (12,3, 13,2)</td>
                <td align="center">0,123</td>
              </tr>
              <tr>
                <td> Plaquetas (*109/l)</td>
                <td align="center">222 (184, 264)</td>
                <td align="center">223 (186, 262)</td>
                <td align="center">226 (184, 272)</td>
                <td align="center">210 (178, 257)</td>
                <td align="center">0,232</td>
              </tr>
              <tr>
                <td> Clearance de creatinina (ml/min)</td>
                <td align="center">84,2 (65,8, 105,8)</td>
                <td align="center">87,5 (69,2, 109,9) <sup>bc</sup> </td>
                <td align="center">78,8 (62,8, 99,4) <sup>ac</sup> </td>
                <td align="center">73,7 (55,8, 88,7) <sup>ab</sup> </td>
                <td align="center">&lt;0,001</td>
              </tr>
              <tr>
                <td> Hemoglobina glicada A1c (%)</td>
                <td align="center">6,2 (5,7, 7,2)</td>
                <td align="center">6,1 (5,7, 6,8) <sup>c</sup> </td>
                <td align="center">6,3 (5,7, 7,4) <sup>c</sup> </td>
                <td align="center">6,8 (6,0, 8,1) <sup>ab</sup> </td>
                <td align="center">&lt;0,001</td>
              </tr>
              <tr>
                <td> LDL-C (mmol/L)</td>
                <td align="center">2,3 (1,8, 2,9)</td>
                <td align="center">2,3 (1,8, 2,8)</td>
                <td align="center">2,4 (1,8, 3,1)</td>
                <td align="center">2,5 (1,9, 3,2)</td>
                <td align="center">0,134</td>
              </tr>
              <tr>
                <td> Lipoprote&#237;na (a) (mg/l)</td>
                <td align="center">204,5 (89,1, 419,2)</td>
                <td align="center">195,1 (86,9, 385,8)</td>
                <td align="center">220,6 (90,7, 450,8)</td>
                <td align="center">221,4 (89,9, 600,1)</td>
                <td align="center">0,150</td>
              </tr>
              <tr>
                <td> &#193;cidos graxos livres (mmol/l)</td>
                <td align="center">0,6 (0,4, 0,8)</td>
                <td align="center">0,5 (0,4, 0,7) <sup>b</sup> </td>
                <td align="center">0,6 (0,4, 0,9) <sup>a</sup> </td>
                <td align="center">0,6 (0,4, 0,8)</td>
                <td align="center">0,014</td>
              </tr>
              <tr>
                <td> Troponina I (ng/ml)</td>
                <td align="center">0,3 (0,1, 1,2)</td>
                <td align="center">0,3 (0,1, 1,0) <sup>b</sup> </td>
                <td align="center">0,5 (0,1, 2,1) <sup>a</sup> </td>
                <td align="center">0,3 (0,1, 1,1)</td>
                <td align="center">0,010</td>
              </tr>
              <tr>
                <td> NT-proBNP (pg/ml)</td>
                <td align="center">241,0 (78,1, 1117,0)</td>
                <td align="center">172,5 (57,6, 658,6) <sup>bc</sup> </td>
                <td align="center">679,8 (150,0, 1939,0) <sup>a</sup> </td>
                <td align="center">1106,0 (225,6, 4091,0) <sup>a</sup> </td>
                <td align="center">&lt;0,001</td>
              </tr>
              <tr>
                <td> D-d&#237;mero (ug/ml)</td>
                <td align="center">0,3 (0,2, 0,5)</td>
                <td align="center">0,3 (0,2, 0,4) <sup>bc</sup> </td>
                <td align="center">0,3 (0,2, 0,6) <sup>a</sup> </td>
                <td align="center">0,4 (0,3, 0,8) <sup>a</sup> </td>
                <td align="center">&lt;0,001</td>
              </tr>
              <tr>
                <td> PCR-as (mg/l)</td>
                <td align="center">3,9 (1,5, 9,6)</td>
                <td align="center">3,3 (1,4, 8,9) <sup>b</sup> </td>
                <td align="center">6,3 (2,0, 10,1) <sup>a</sup> </td>
                <td align="center">4,4 (1,5, 11,2)</td>
                <td align="center">0,011</td>
              </tr>
              <tr>
                <td> Big endotelina-1 (pmol/l)</td>
                <td align="center">0,34 (0,23, 0,53)</td>
                <td align="center">0,30 (0,21, 0,45) <sup>bc</sup> </td>
                <td align="center">0,41 (0,28, 0,58) <sup>ac</sup> </td>
                <td align="center">0,58 (0,36, 0,92) <sup>ab</sup> </td>
                <td align="center">&lt;0,001</td>
              </tr>
              <tr>
                <td colspan="6">
                  <bold>Medicamentos, n (%)</bold>
                </td>
              </tr>
              <tr>
                <td> Aspirina</td>
                <td align="center">757 (98,8)</td>
                <td align="center">527 (99,2)</td>
                <td align="center">129 (97,7)</td>
                <td align="center">101 (98,1)</td>
                <td align="center">0,148</td>
              </tr>
              <tr>
                <td> Clopidogrel</td>
                <td align="center">519 (67,8)</td>
                <td align="center">350 (65,9)</td>
                <td align="center">99 (75,0)</td>
                <td align="center">70 (68,0)</td>
                <td align="center">0,135</td>
              </tr>
              <tr>
                <td> Ticagrelor</td>
                <td align="center">220 (28,7)</td>
                <td align="center">168 (31,6)</td>
                <td align="center">29 (22,0)</td>
                <td align="center">23 (22,3)</td>
                <td align="center">0,027</td>
              </tr>
              <tr>
                <td> Anticoagulantes orais</td>
                <td align="center">22 (2,9)</td>
                <td align="center">11 (2,1)</td>
                <td align="center">7 (5,3)</td>
                <td align="center">4 (3,9)</td>
                <td align="center">0,086</td>
              </tr>
              <tr>
                <td> Estatinas</td>
                <td align="center">748 (97,7)</td>
                <td align="center">518 (97,6)</td>
                <td align="center">129 (97,7)</td>
                <td align="center">101 (98,1)</td>
                <td align="center">1,000</td>
              </tr>
              <tr>
                <td> &#946; bloqueadores</td>
                <td align="center">669 (87,3)</td>
                <td align="center">456 (85,9)</td>
                <td align="center">118 (89,4)</td>
                <td align="center">95 (92,2)</td>
                <td align="center">0,152</td>
              </tr>
              <tr>
                <td> IECA/BRA</td>
                <td align="center">487 (63,6)</td>
                <td align="center">364 (68,5) <sup>bc</sup> </td>
                <td align="center">75 (56,8) <sup>a</sup> </td>
                <td align="center">48 (46,6) <sup>a</sup> </td>
                <td align="center">&lt;0,001</td>
              </tr>
              <tr>
                <td> Espironolactona</td>
                <td align="center">84 (11,0)</td>
                <td align="center">38 (7,2) <sup>bc</sup> </td>
                <td align="center">22 (16,7) <sup>a</sup> </td>
                <td align="center">24 (23,3) <sup>a</sup> </td>
                <td align="center">&lt;0,001</td>
              </tr>
              <tr>
                <td> Diur&#233;ticos</td>
                <td align="center">154 (20,1)</td>
                <td align="center">70 (13,2) <sup>bc</sup> </td>
                <td align="center">40 (30,3) <sup>a</sup> </td>
                <td align="center">44 (42,7) <sup>a</sup> </td>
                <td align="center">&lt;0,001</td>
              </tr>
              <tr>
                <td> Inibidores da bomba de pr&#243;tons</td>
                <td align="center">413 (53,9)</td>
                <td align="center">291 (54,8)</td>
                <td align="center">67 (50,8)</td>
                <td align="center">55 (53,4)</td>
                <td align="center">0,702</td>
              </tr>
            </tbody>
          </table>
          <table-wrap-foot>
            <fn id="TFN1">
              <p>
                <italic>IAMSSST: infarto do mioc&#225;rdio sem supradesnivelamento do segmento ST; FEVE: fra&#231;&#227;o de eje&#231;&#227;o ventricular esquerda; AIT: ataque isqu&#234;mico transit&#243;rio; DAC: doen&#231;a arterial coronariana; RDW: amplitude de distribui&#231;&#227;o de eritr&#243;citos; LDL-C: colesterol de lipoprote&#237;na de baixa densidade; NT-proBPN: pept&#237;deo natriur&#233;tico tipo N-terminal pr&#243;-B; PCR-as: prote&#237;na C reativa de alta sensibilidade; IECA: inibidores da enzima conversora da angiotensina; BRA: bloqueador de receptor de angiotensina. <sup><italic>a</italic></sup> p&lt;0,0167 versus o grupo de escore SYNTAX baixo. <sup><italic>b</italic></sup> p&lt;0,0167 versus o grupo de escore SYNTAX intermedi&#225;rio. <sup><italic>c</italic></sup> p&lt;0,0167 versus o grupo de escore SYNTAX alto.</italic>
              </p>
            </fn>
          </table-wrap-foot>
        </table-wrap>
      </p>
      <p>De acordo com a an&#225;lise de correla&#231;&#227;o de Spearman, houve correla&#231;&#227;o significativa entre a big ET-1 e o SS (r=0,378, p&lt;0,001). A curva de suaviza&#231;&#227;o indicou uma correla&#231;&#227;o positiva entre o n&#237;vel de big ET-1 plasm&#225;tica e o SS, ap&#243;s ajuste para poss&#237;veis fatores de confus&#227;o ( <xref rid="f01" ref-type="fig">Figura central</xref> ). A curva ROC do n&#237;vel de big ET-1 plasm&#225;tica para prever SS intermedi&#225;rio a alto &#233; exibida na <xref rid="f02" ref-type="fig">Figura 1</xref> . A &#225;rea sob a curva (AUC) foi de 0,695 (IC 95%: 0,661-0,727, p&lt;0,001) e o corte ideal do n&#237;vel de big ET-1 plasm&#225;tica foi de 0,35 pmol/l, com sensibilidade de 68,9% e especificidade de 62,9%. Com base nesse corte, os pacientes foram categorizados em dois grupos: big ET-1 &#8804;0,35 pmol/l e big ET-1 &gt;0,35 pmol/l. Independentemente de entrar nos modelos de regress&#227;o log&#237;stica univariada como uma vari&#225;vel cont&#237;nua ou como uma vari&#225;vel categ&#243;rica, o n&#237;vel de big ET-1 plasm&#225;tica foi significativamente associado ao SS intermedi&#225;rio a alto. Para avaliar a associa&#231;&#227;o entre o n&#237;vel de big ET-1 plasm&#225;tica e o SS, tr&#234;s modelos com diferentes covari&#225;veis foram constru&#237;dos e apontaram resultados consistentes ( <xref rid="t2" ref-type="table">Tabela 2</xref> ). Ap&#243;s ajuste para idade, sexo feminino, &#237;ndice de massa corporal, classe Killip, FEVE, insufici&#234;ncia card&#237;aca, hipertens&#227;o, diabetes mellitus, acidente vascular cerebral/AIT, doen&#231;a arterial perif&#233;rica, tabagismo, hemoglobina, amplitude de distribui&#231;&#227;o de eritr&#243;citos, clearance de creatinina, hemoglobina A1c, colesterol de lipoprote&#237;na de baixa densidade, lipoprote&#237;na (a), &#225;cido graxo livre, d-d&#237;mero, troponina I, NT-proBNP e PCR-as na an&#225;lise de regress&#227;o log&#237;stica multivariada com m&#233;todo de RV retroativo, a big ET-1 alta ainda foi um preditor independente de SS intermedi&#225;rio a alto em pacientes com IAMSSST [RC (IC 95%): 1,110 (1,053-1,170), p&lt;0,001]. Pacientes com n&#237;vel de ET-1 plasm&#225;tica &gt;0,35 pmol/l eram notavelmente mais propensos a ter um SS intermedi&#225;rio a alto do que aqueles com n&#237;vel de ET-1 plasm&#225;tico &#8804;0,35 pmol/l [RC (IC 95%): 2,962 (2,073-4,233), p&lt;0,001] ( <xref rid="t2" ref-type="table">Tabela 2</xref> ). A an&#225;lise de subgrupo demonstrou que a associa&#231;&#227;o entre big ET-1 e SS intermedi&#225;rio a alto foi constante em subgrupos de idade, sexo, insufici&#234;ncia card&#237;aca, hipertens&#227;o, diabetes mellitus, doen&#231;a arterial perif&#233;rica, insufici&#234;ncia renal e tabagismo (todos p&gt;0,05 para intera&#231;&#227;o) ( <xref rid="f03" ref-type="fig">Figura 2</xref> ).</p>
      <p>
        <fig id="f01">
          <label>Figura Central</label>
          <caption>
            <title>: Associa&#231;&#227;o entre N&#237;vel de Big Endotelina-1 Plasm&#225;tica e a Gravidade da Doen&#231;a Arterial Coronariana em Pacientes com Infarto do Mioc&#225;rdio sem Supradesnivelamento do Segmento ST</title>
          </caption>
          <attrib>
            <italic>A rela&#231;&#227;o entre o n&#237;vel de big endotelina-1 plasm&#225;tica e o escore SYNTAX por ajuste de curva suave.</italic>
          </attrib>
          <attrib>
            <italic><sup><italic>*</italic></sup> Padronizado para feminino sexo, insufici&#234;ncia card&#237;aca, hipertens&#227;o, diabetes mellitus, doen&#231;a arterial perif&#233;rica, hemoglobina, amplitude de distribui&#231;&#227;o de eritr&#243;citos, lipoprote&#237;na (a), &#225;cidos graxos livres, e NT-ProBNP. O histograma indicou a distribui&#231;&#227;o de n&#237;veis de big ET-1 plasm&#225;tica.</italic>
          </attrib>
          <graphic xlink:href="1678-4170-abc-120-02-e20220294-20294-gf01.tif"/></fig>
      </p>
      <p>
        <fig id="f02">
          <label>Figura 1</label>
          <caption>
            <title>&#8211; Curva de caracter&#237;stica de opera&#231;&#227;o do receptor de n&#237;vel de big endotelina-1 plasm&#225;tica para detec&#231;&#227;o de escore SYNTAX de intermedi&#225;rio a alto.</title>
          </caption>
          <graphic xlink:href="1678-4170-abc-120-02-e20220294-20294-gf02.tif"/></fig>
      </p>
      <p>
        <fig id="f03">
          <label>Figura 2</label>
          <caption>
            <title>&#8211; An&#225;lise de subgrupo para associa&#231;&#245;es entre n&#237;vel de big endotelina-1 plasm&#225;tica e escore SYNTAX de intermedi&#225;rio a alto em pacientes com IAMSSST. IAMSSST: infarto do mioc&#225;rdio sem supradesnivelamento do segmento ST; ET-1: endotelina-1; IC: intervalo de confian&#231;a.</title>
            <p>* Padronizado para feminino sexo, insufici&#234;ncia card&#237;aca, hipertens&#227;o, diabetes mellitus, doen&#231;a arterial perif&#233;rica, hemoglobina, amplitude de distribui&#231;&#227;o de eritr&#243;citos, lipoprote&#237;na (a), &#225;cidos graxos livres, e NT-ProBNP.</p>
          </caption>
          <graphic xlink:href="1678-4170-abc-120-02-e20220294-20294-gf03.tif"/></fig>
      </p>
    </sec>
    <sec sec-type="discussion">
      <title>Discuss&#227;o</title>
      <p>O presente estudo demonstrou uma correla&#231;&#227;o positiva significativa entre big ET-1 e SS em pacientes com IAMSSST. O n&#237;vel de big ET-1 plasm&#225;tica elevado foi um preditor independente para SS intermedi&#225;rio a alto. A an&#225;lise da curva ROC indicou que o desempenho discriminativo de big ET-1 &#233; moderado, e o valor de corte ideal do n&#237;vel de big ET-1 plasm&#225;tica para SS intermedi&#225;rio a alto foi de 0,35 pmol/L. Os resultados das an&#225;lises de subgrupos foram consistentes com os dos pacientes em geral.</p>
      <p>Com o desenvolvimento de cuidados intensivos e procedimentos invasivos, o progn&#243;stico de IAMSSST melhorou significativamente nas &#250;ltimas d&#233;cadas. <sup><xref rid="B1" ref-type="bibr">1</xref> , <xref rid="B2" ref-type="bibr">2</xref> </sup> De acordo com as diretrizes cl&#237;nicas, a estratifica&#231;&#227;o de risco &#233; recomendada para pacientes com IAMSSST para determinar a estrat&#233;gia de controle apropriada. <sup><xref rid="B1" ref-type="bibr">1</xref> , <xref rid="B2" ref-type="bibr">2</xref> </sup> Diversos padr&#245;es angiogr&#225;ficos de DAC podem ser encontrados em pacientes com IAMSSST, que t&#234;m uma influ&#234;ncia proeminente nas escolhas de tratamento e progn&#243;stico subsequente. <sup><xref rid="B1" ref-type="bibr">1</xref> , <xref rid="B2" ref-type="bibr">2</xref> </sup> O escore SYNTAX &#233; um sistema de escore anat&#244;mico cl&#225;ssico recomendado para quantificar a complexidade da DAC e foi confirmado como um preditor independente de resultados adversos em pacientes com IAMSSST. <sup><xref rid="B3" ref-type="bibr">3</xref> - <xref rid="B5" ref-type="bibr">5</xref> </sup> Uma grande propor&#231;&#227;o de pacientes com IAMSSST tende a ter DAC multiarterial. <sup><xref rid="B1" ref-type="bibr">1</xref> , <xref rid="B2" ref-type="bibr">2</xref> </sup> A identifica&#231;&#227;o precoce de pacientes com diferentes gravidades de DAC e a ado&#231;&#227;o de estrat&#233;gias de manejo adequadas foram de grande import&#226;ncia para reduzir desfechos adversos em pacientes com IAMSSST. <sup><xref rid="B1" ref-type="bibr">1</xref> , <xref rid="B2" ref-type="bibr">2</xref> , <xref rid="B6" ref-type="bibr">6</xref> </sup> </p>
      <p>A endotelina &#233; um pept&#237;deo de 21 amino&#225;cidos descoberto pela primeira vez em 1985. <sup><xref rid="B18" ref-type="bibr">18</xref></sup> Posteriormente, tr&#234;s isoformas da ET: ET-1, ET-2, e ET-3, foram identificadas. <sup><xref rid="B7" ref-type="bibr">7</xref> - <xref rid="B9" ref-type="bibr">9</xref> </sup> A ET-1, a principal isoforma no sistema cardiovascular humano, pode ser produzida por uma variedade de c&#233;lulas, incluindo c&#233;lulas endoteliais vasculares, c&#233;lulas do m&#250;sculo liso, cardiomi&#243;citos e fibroblastos. <sup><xref rid="B8" ref-type="bibr">8</xref> , <xref rid="B9" ref-type="bibr">9</xref> </sup> A ET-1 &#233; um pept&#237;deo biologicamente ativo derivado de um intermedi&#225;rio de 39 amino&#225;cidos, a big ET-1. Devido a seu clearance r&#225;pido e meia-vida curta, a medi&#231;&#227;o da ET-1 em circula&#231;&#227;o &#233; relativamente dif&#237;cil e muitas vezes subestimada. Assim, a big ET-1, o precursor com meia-vida mais longa, poderia atuar como um indicador mais pr&#225;tico para a ativa&#231;&#227;o do sistema endotelial. <sup><xref rid="B7" ref-type="bibr">7</xref> - <xref rid="B9" ref-type="bibr">9</xref> </sup> Pesquisas anteriores revelaram que a ET-1 desempenha um papel importante na disfun&#231;&#227;o endotelial, inflama&#231;&#227;o e remodela&#231;&#227;o mioc&#225;rdica. <sup><xref rid="B7" ref-type="bibr">7</xref> - <xref rid="B9" ref-type="bibr">9</xref> </sup> Todos esses s&#227;o fatores de risco bem estabelecidos para a ocorr&#234;ncia, progress&#227;o e deteriora&#231;&#227;o da DAC.</p>
      <p>As concentra&#231;&#245;es plasm&#225;ticas de ET-1 e big ET-1 foram detectadas como elevadas em pacientes com IAM, <sup><xref rid="B8" ref-type="bibr">8</xref></sup> relativamente maior em pacientes com IAMCSST do que naqueles com IAMSSST. <sup><xref rid="B19" ref-type="bibr">19</xref></sup> Tsutamoto, et al., <sup><xref rid="B20" ref-type="bibr">20</xref></sup> descobriram que a ET-1 est&#225; associada &#224; modula&#231;&#227;o da remodela&#231;&#227;o do VE p&#243;s-infarto. <sup><xref rid="B20" ref-type="bibr">20</xref></sup> Um estudo prospectivo de 128 pacientes com IAMCSST submetidos a ICP prim&#225;ria demonstrou que o n&#237;vel de ET-1 na admiss&#227;o foi um preditor independente de no-reflow e redu&#231;&#227;o da fra&#231;&#227;o de eje&#231;&#227;o ventricular esquerda. <sup><xref rid="B11" ref-type="bibr">11</xref></sup> Al&#233;m disso, a big ET-1 tamb&#233;m foi identificada como um fator de risco para trombose de stent em pacientes submetidos a implante de stent coron&#225;rio. <sup><xref rid="B21" ref-type="bibr">21</xref></sup> Todos estes desempenham pap&#233;is importantes no processo patol&#243;gico do IAM, levando a desfechos cl&#237;nicos desfavor&#225;veis. Numerosos estudos indicam que ET-1 e big ET-1 s&#227;o preditores de eventos adversos em pacientes com IAM. <sup><xref rid="B11" ref-type="bibr">11</xref> - <xref rid="B15" ref-type="bibr">15</xref> </sup> </p>
      <p>Apesar da rela&#231;&#227;o entre ET-1 e progn&#243;stico ter sido extensivamente estudada, a associa&#231;&#227;o entre big ET-1 e a gravidade da DAC em pacientes com IAM ainda n&#227;o foi explorada. V&#225;rios estudos investigaram a rela&#231;&#227;o de ET-1 com a presen&#231;a e gravidade de DAC em pacientes sem IM &#237;ndice, mas chegaram a conclus&#245;es controversas. <sup><xref rid="B19" ref-type="bibr">19</xref> , <xref rid="B22" ref-type="bibr">22</xref> - <xref rid="B25" ref-type="bibr">25</xref> </sup> Em uma coorte de pacientes submetidos &#224; coronariografia sem IAM prevalente, os n&#237;veis de ET-1 n&#227;o foram relacionados &#224; presen&#231;a ou gravidade da DAC. <sup><xref rid="B19" ref-type="bibr">19</xref></sup> Por outro lado, Kanaya et al., <sup><xref rid="B22" ref-type="bibr">22</xref></sup> realizaram uma an&#225;lise transversal de 961 pacientes e revelaram que a ET-1 estava significativamente relacionada &#224; presen&#231;a de DAC em mulheres de todas as idades, mas apenas em homens &#8805;75 anos. <sup><xref rid="B22" ref-type="bibr">22</xref></sup> Outro estudo de pacientes chineses submetidos &#224; angiotomografia computadorizada coronariana mostrou que a big ET-1 estava significativamente associada &#224; presen&#231;a de placas n&#227;o calcificadas/placas mistas e poderia atuar como um preditor independente de calcifica&#231;&#227;o da art&#233;ria coron&#225;ria, todas as quais foram indicadas como relacionadas &#224; carga ateroscler&#243;tica e resultados adversos. <sup><xref rid="B23" ref-type="bibr">23</xref> , <xref rid="B24" ref-type="bibr">24</xref> </sup> Por outro lado, a big ET-1 demonstrou estar independentemente relacionada &#224; gravidade da DAC est&#225;vel em outra coorte de 963 pacientes. <sup><xref rid="B25" ref-type="bibr">25</xref></sup> Quanto aos pacientes com IAM, ainda faltam</p>
      <p>estudos sobre a associa&#231;&#227;o entre big ET-1 e a gravidade da DAC. At&#233; onde sabemos, o presente estudo indicou que big ET-1 &#233; um marcador independente da gravidade da DAC avaliada pelo SS em pacientes que apresentam IAMSSST pela primeira vez.</p>
      <p>As explica&#231;&#245;es para a associa&#231;&#227;o entre big ET-1 e gravidade da DAC em IAMSSST n&#227;o foram totalmente elucidadas e podem ser m&#250;ltiplas. Primeiramente, a big ET-1 &#233; um marcador pr&#225;tico de disfun&#231;&#227;o endotelial caracterizada por comprometimento da vasodilata&#231;&#227;o. <sup><xref rid="B26" ref-type="bibr">26</xref> , <xref rid="B27" ref-type="bibr">27</xref> </sup> Est&#225; bem estabelecido que a disfun&#231;&#227;o endotelial participa do desenvolvimento de IAMSSST. <sup><xref rid="B12" ref-type="bibr">12</xref> , <xref rid="B14" ref-type="bibr">14</xref> , <xref rid="B28" ref-type="bibr">28</xref> , <xref rid="B29" ref-type="bibr">29</xref> </sup> Al&#233;m disso, a ET-1 &#233; um vasoconstritor potente que &#233; essencial no mecanismo fisiopatol&#243;gico do IAMSSST. <sup><xref rid="B27" ref-type="bibr">27</xref></sup> Por outro lado, a ET-1 elevada pode levar &#224; diminui&#231;&#227;o da s&#237;ntese e aumento da</p>
      <p>degrada&#231;&#227;o do &#243;xido n&#237;trico. <sup><xref rid="B7" ref-type="bibr">7</xref> - <xref rid="B9" ref-type="bibr">9</xref> </sup> Assim, a ET-1 desempenha um papel crucial na manuten&#231;&#227;o de um equil&#237;brio entre vasoconstri&#231;&#227;o e vasodilata&#231;&#227;o da art&#233;ria coron&#225;ria. <sup><xref rid="B27" ref-type="bibr">27</xref></sup> A diminui&#231;&#227;o do fluxo sangu&#237;neo devido &#224; estenose arterial &#233; um dos est&#237;mulos mais importantes na modula&#231;&#227;o da produ&#231;&#227;o e libera&#231;&#227;o de ET-1, que pode atuar como um elo entre a ET-1 e o SS. <sup><xref rid="B29" ref-type="bibr">29</xref></sup> Em segundo lugar, a ET-1 est&#225; intimamente relacionada &#224; ativa&#231;&#227;o da inflama&#231;&#227;o. <sup><xref rid="B7" ref-type="bibr">7</xref> - <xref rid="B9" ref-type="bibr">9</xref> </sup> Est&#225; bem estabelecido que a inflama&#231;&#227;o &#233; um fator inicial no complicado mecanismo da DAC. <sup><xref rid="B30" ref-type="bibr">30</xref></sup> Al&#233;m das c&#233;lulas endoteliais, uma variedade de c&#233;lulas inflamat&#243;rias, como macr&#243;fagos e leuc&#243;citos polimorfonucleares, tamb&#233;m podem produzir ET-1. <sup><xref rid="B31" ref-type="bibr">31</xref> , <xref rid="B32" ref-type="bibr">32</xref> </sup> Ao aumentar a express&#227;o de mol&#233;culas adesivas, a ET-1 poderia induzir a ades&#227;o de neutr&#243;filos &#224;s c&#233;lulas endoteliais da art&#233;ria coron&#225;ria e c&#233;lulas do mioc&#225;rdio. <sup><xref rid="B33" ref-type="bibr">33</xref></sup> Al&#233;m disso, a ET-1 elevada est&#225; associada ao aumento do stress oxidativo e ativa&#231;&#227;o de v&#225;rios fatores inflamat&#243;rios na cascata inflamat&#243;ria, que contribuem para a forma&#231;&#227;o, agravamento e ruptura de placas ateroscler&#243;ticas. <sup><xref rid="B34" ref-type="bibr">34</xref> , <xref rid="B35" ref-type="bibr">35</xref> </sup> Finalmente, pesquisas anteriores revelaram a rela&#231;&#227;o da ET-1 com les&#227;o de reperfus&#227;o, obstru&#231;&#227;o microvascular, forma&#231;&#227;o de circula&#231;&#227;o colateral coron&#225;ria, calcifica&#231;&#227;o da art&#233;ria coron&#225;ria, remodela&#231;&#227;o vascular e mioc&#225;rdica. <sup><xref rid="B7" ref-type="bibr">7</xref> - <xref rid="B9" ref-type="bibr">9</xref> , <xref rid="B24" ref-type="bibr">24</xref> , <xref rid="B36" ref-type="bibr">36</xref> </sup> Al&#233;m disso, foi indicado que a ET-1 est&#225; associada &#224; agrega&#231;&#227;o plaquet&#225;ria promovida e ao estado pr&#243;-tromb&#243;tico ativado. <sup><xref rid="B7" ref-type="bibr">7</xref> , <xref rid="B37" ref-type="bibr">37</xref> </sup> Tudo isso pode contribuir para a progress&#227;o das les&#245;es ateroscler&#243;ticas.</p>
      <p>No presente estudo, a an&#225;lise de subgrupo demonstrou uma rela&#231;&#227;o consistente entre o n&#237;vel de big ET-1 plasm&#225;tica e o SS. Essa correla&#231;&#227;o positiva entre big ET-1 e gravidade da DAC apresenta novas ideias para a pr&#225;tica cl&#237;nica. O n&#237;vel de big ET-1 plasm&#225;tica pode atuar como um marcador &#250;til para prever a gravidade da DAC em pacientes com IAMSSST, o que pode ajudar na avalia&#231;&#227;o do progn&#243;stico e na orienta&#231;&#227;o do tratamento. Por outro lado, v&#225;rios estudos tentaram explorar a efic&#225;cia e a seguran&#231;a dos antagonistas dos receptores de endotelina em pacientes com aterosclerose. <sup><xref rid="B8" ref-type="bibr">8</xref> , <xref rid="B38" ref-type="bibr">38</xref> </sup> Estudos futuros podem ajudar a elucidar os mecanismos fisiopatol&#243;gicos exatos da ET-1 no IAMSSST e fornecer mais evid&#234;ncias para a preven&#231;&#227;o e tratamento da aterosclerose.</p>
      <p>V&#225;rias limita&#231;&#245;es precisam ser observadas neste estudo. Primeiro, o presente estudo foi um estudo transversal com defeitos inerentes. A rela&#231;&#227;o entre o n&#237;vel de big ET-1 plasm&#225;tica e o SS s&#243; pode ser inferida como correlativa, e n&#227;o como causal. Entretanto, a discrimina&#231;&#227;o da big ET-1 foi apenas moderada. &#201; necess&#225;rio testar esse biomarcador em futuros ensaios cl&#237;nicos, de forma a aplic&#225;-lo em contextos cl&#237;nicos de rotina. Neste estudo transversal, os medicamentos antes do infarto do mioc&#225;rdio podem ser mais importantes. No entanto, devido ao vi&#233;s de mem&#243;ria dos pacientes e aos dados ausentes, n&#227;o foi poss&#237;vel obter dados precisos sobre os medicamentos antes do infarto do mioc&#225;rdio. Como alternativa, apresentamos medicamentos ap&#243;s infarto do mioc&#225;rdio. Em segundo lugar, embora a</p>
      <p>regress&#227;o log&#237;stica multivariada tenha sido realizada para ajustar poss&#237;veis fatores de confus&#227;o, a associa&#231;&#227;o entre big ET-1 e SS pode ser confundida por outros fatores n&#227;o medidos. Em terceiro lugar, este estudo foi realizado na popula&#231;&#227;o chinesa em um &#250;nico centro. Portanto, os resultados devem ser extrapolados para outras popula&#231;&#245;es com cautela. Al&#233;m disso, o tamanho da amostra foi relativamente pequeno, o que pode limitar o poder estat&#237;stico. Finalmente, medimos apenas o n&#237;vel de big ET-1 plasm&#225;tica na linha de base, mas n&#227;o temos dados em s&#233;rie de grandes concentra&#231;&#245;es de ET-1. O monitoramento din&#226;mico de grandes n&#237;veis de ET-1 plasm&#225;tica pode garantir mais informa&#231;&#245;es sobre a gravidade da DAC.</p>
    </sec>
    <sec sec-type="conclusions">
      <title>Conclus&#227;o</title>
      <p>O n&#237;vel de big ET-1 plasm&#225;tica foi significativamente correlacionado com a gravidade da DAC em pacientes com IAMSSST, conforme avaliado pelo SS. O n&#237;vel de big ET-1 plasm&#225;tica elevado foi um preditor independente para SS intermedi&#225;rio a alto.</p>
      <p>
        <table-wrap id="t2">
          <label>Tabela 2</label>
          <caption>
            <title>&#8211; Associa&#231;&#227;o entre n&#237;vel de big ET-1 plasm&#225;tica e escore SYNTAX de intermedi&#225;rio a alto de acordo com a regress&#227;o log&#237;stica</title>
          </caption>
          <table frame="hsides" rules="groups">
            <colgroup width="11%">
              <col/>
              <col/>
              <col/>
              <col/>
              <col/>
              <col/>
              <col/>
              <col/>
              <col/>
              <col/>
            </colgroup>
            <thead>
              <tr>
                <th rowspan="3" align="left">Vari&#225;veis</th>
                <th colspan="2" rowspan="2">Regress&#227;o log&#237;stica univariada</th>
                <th colspan="6">Regress&#227;o log&#237;stica multivariada</th>
              </tr>
              <tr>
                <th colspan="2">Modelo 1 <sup><bold>a</bold></sup> </th>
                <th colspan="2">Modelo 2 <sup><bold>b</bold></sup> </th>
                <th colspan="2">Modelo 3 <sup><bold>c</bold></sup> </th>
              </tr>
              <tr>
                <th>RC (IC 95%)</th>
                <th>p valor</th>
                <th>RC (IC 95%)</th>
                <th>p valor</th>
                <th>RC (IC 95%)</th>
                <th>p valor</th>
                <th>RC (IC 95%)</th>
                <th>p valor</th>
              </tr>
            </thead>
            <tbody>
              <tr>
                <td colspan="3">
                  <bold>N&#237;vel de big ET-1 plasm&#225;tica como vari&#225;vel cont&#237;nua</bold>
                </td>
                <td> </td>
                <td> </td>
                <td> </td>
                <td> </td>
                <td> </td>
                <td> </td>
              </tr>
              <tr>
                <td> Big ET-1, por 0,1 pmol/l</td>
                <td align="center">1,171 (1,115-1,230)</td>
                <td align="center">&lt;0,001</td>
                <td align="center">1,156 (1,101-1,215)</td>
                <td align="center">&lt;0,001</td>
                <td align="center">1,111 (1,051-1,175)</td>
                <td align="center">&lt;0,001</td>
                <td align="center">1,110 (1,053-1,170)</td>
                <td align="center">&lt;0,001</td>
              </tr>
              <tr>
                <td colspan="3">
                  <bold>N&#237;vel de big ET-1 plasm&#225;tica como vari&#225;vel categ&#243;rica</bold>
                </td>
                <td> </td>
                <td> </td>
                <td> </td>
                <td> </td>
                <td> </td>
                <td> </td>
              </tr>
              <tr>
                <td> Big ET-1 &#8804;0,35 pmol/l</td>
                <td colspan="2" align="center">1 (refer&#234;ncia)</td>
                <td colspan="2" align="center">1 (refer&#234;ncia)</td>
                <td colspan="2" align="center">1 (refer&#234;ncia)</td>
                <td colspan="2" align="center">1 (refer&#234;ncia)</td>
              </tr>
              <tr>
                <td> Big ET-1 &gt;0,35 pmol/l</td>
                <td align="center">3,762 (2,711-5,221)</td>
                <td align="center">&lt;0,001</td>
                <td align="center">3,450 (2,474-4,809)</td>
                <td align="center">&lt;0,001</td>
                <td align="center">2,796 (1,937-4,036)</td>
                <td align="center">&lt;0,001</td>
                <td align="center">2,962 (2,073-4,233)</td>
                <td align="center">&lt;0,001</td>
              </tr>
            </tbody>
          </table>
          <table-wrap-foot>
            <fn id="TFN3">
              <p>
                <italic>RC: raz&#227;o de chance; IC: intervalo de confian&#231;a; ET-1: endotelina-1. a) O Modelo 1 incluiu idade, sexo e n&#237;vel de big ET-1 plasm&#225;tica. b) O Modelo 2 incluiu idade, sexo, IMC, classe Killip, FEVE, insufici&#234;ncia card&#237;aca, hipertens&#227;o, diabetes mellitus, acidente vascular cerebral/AIT, doen&#231;a arterial perif&#233;rica, tabagismo, hemoglobina, amplitude de distribui&#231;&#227;o de eritr&#243;citos, clearance de creatinina, hemoglobina A1c, LDL-C, lipoprote&#237;na (a), &#225;cido graxo livre, d-d&#237;mero, troponina I, NT-proBNP, PCR-as e n&#237;vel de big ET-1 plasm&#225;tica. c) O Modelo 3 incluiu idade, sexo, IMC, classe Killip, FEVE, insufici&#234;ncia card&#237;aca, hipertens&#227;o, diabetes mellitus, acidente vascular cerebral/AIT, doen&#231;a arterial perif&#233;rica, tabagismo, hemoglobina, amplitude de distribui&#231;&#227;o de eritr&#243;citos, clearance de creatinina, hemoglobina A1c, LDL-C, lipoprote&#237;na (a), &#225;cido graxo livre, d-d&#237;mero, troponina I, NT-proBNP, PCR-as e n&#237;vel de big ET-1 plasm&#225;tica com m&#233;todo de RV retroativa.</italic>
              </p>
            </fn>
          </table-wrap-foot>
        </table-wrap>
      </p>
    </sec>
  </body>
  <back>
    <ref-list>
      <title>Refer&#234;ncias</title>
      <ref id="B1">
        <label>1</label>
        <mixed-citation>1. Amsterdam EA , Wenger NK , Brindis RG , Casey DE Jr. , Ganiats TG , Holmes DR Jr ., et al . 2014 AHA/ACC Guideline for the Management of Patients with Non-ST-Elevation Acute Coronary Syndromes: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines . J Am Coll Cardiol . 2014 ; 64 ( 24 ): e139 - 228 . DOI: 10.1016/j.jacc.2014.09.017 </mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Amsterdam</surname>
              <given-names>EA</given-names>
            </name>
            <name>
              <surname>Wenger</surname>
              <given-names>NK</given-names>
            </name>
            <name>
              <surname>Brindis</surname>
              <given-names>RG</given-names>
            </name>
            <name>
              <surname>Casey</surname>
              <given-names>DE</given-names>
              <suffix>Jr.</suffix>
            </name>
            <name>
              <surname>Ganiats</surname>
              <given-names>TG</given-names>
            </name>
            <name>
              <surname>Holmes</surname>
              <given-names>DR</given-names>
              <suffix>Jr</suffix>
            </name>
            <etal>et al</etal>
          </person-group>
          <article-title>2014 AHA/ACC Guideline for the Management of Patients with Non-ST-Elevation Acute Coronary Syndromes: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines</article-title>
          <source>J Am Coll Cardiol</source>
          <year>2014</year>
          <volume>64</volume>
          <issue>24</issue>
          <fpage>e139</fpage>
          <lpage>e228</lpage>
          <issue-id pub-id-type="doi">10.1016/j.jacc.2014.09.017</issue-id>
        </element-citation>
      </ref>
      <ref id="B2">
        <label>2</label>
        <mixed-citation>2. Collet JP , Thiele H , Barbato E , Barth&#233;l&#233;my O , Bauersachs J , Bhatt DL , et al . 2020 ESC Guidelines for the management of acute coronary syndromes in patients presenting without persistent ST-segment elevation . Eur Heart J . 2020 ; 42 ( 14 ): 1289 - 367 . DOI: 10.1093/eurheartj/ehaa575 </mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Collet</surname>
              <given-names>JP</given-names>
            </name>
            <name>
              <surname>Thiele</surname>
              <given-names>H</given-names>
            </name>
            <name>
              <surname>Barbato</surname>
              <given-names>E</given-names>
            </name>
            <name>
              <surname>Barth&#233;l&#233;my</surname>
              <given-names>O</given-names>
            </name>
            <name>
              <surname>Bauersachs</surname>
              <given-names>J</given-names>
            </name>
            <name>
              <surname>Bhatt</surname>
              <given-names>DL</given-names>
            </name>
            <etal>et al</etal>
          </person-group>
          <article-title>2020 ESC Guidelines for the management of acute coronary syndromes in patients presenting without persistent ST-segment elevation</article-title>
          <source>Eur Heart J</source>
          <year>2020</year>
          <volume>42</volume>
          <issue>14</issue>
          <fpage>1289</fpage>
          <lpage>1367</lpage>
          <pub-id pub-id-type="doi">10.1093/eurheartj/ehaa575</pub-id>
        </element-citation>
      </ref>
      <ref id="B3">
        <label>3</label>
        <mixed-citation>3. Palmerini T , Genereux P , Caixeta A , Cristea E , Lansky A , Mehran R , et al . Prognostic value of the SYNTAX score in patients with acute coronary syndromes undergoing percutaneous coronary intervention: analysis from the ACUITY (Acute Catheterization and Urgent Intervention Triage StrategY) trial . J Am Coll Cardiol . 2011 ; 57 ( 24 ): 2389 - 97 . DOI: 10.1016/j.jacc.2011.02.032 </mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Palmerini</surname>
              <given-names>T</given-names>
            </name>
            <name>
              <surname>Genereux</surname>
              <given-names>P</given-names>
            </name>
            <name>
              <surname>Caixeta</surname>
              <given-names>A</given-names>
            </name>
            <name>
              <surname>Cristea</surname>
              <given-names>E</given-names>
            </name>
            <name>
              <surname>Lansky</surname>
              <given-names>A</given-names>
            </name>
            <name>
              <surname>Mehran</surname>
              <given-names>R</given-names>
            </name>
            <etal>et al</etal>
          </person-group>
          <article-title>Prognostic value of the SYNTAX score in patients with acute coronary syndromes undergoing percutaneous coronary intervention: analysis from the ACUITY (Acute Catheterization and Urgent Intervention Triage StrategY) trial</article-title>
          <source>J Am Coll Cardiol</source>
          <year>2011</year>
          <volume>57</volume>
          <issue>24</issue>
          <fpage>2389</fpage>
          <lpage>2397</lpage>
          <issue-id pub-id-type="doi">10.1016/j.jacc.2011.02.032</issue-id>
        </element-citation>
      </ref>
      <ref id="B4">
        <label>4</label>
        <mixed-citation>4. Sianos G , Morel MA , Kappetein AP , Morice MC , Colombo A , Dawkins K , et al . The SYNTAX Score: an angiographic tool grading the complexity of coronary artery disease . EuroIntervention . 2005 ; 1 ( 2 ): 219 - 27 . PMID: 19758907 </mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Sianos</surname>
              <given-names>G</given-names>
            </name>
            <name>
              <surname>Morel</surname>
              <given-names>MA</given-names>
            </name>
            <name>
              <surname>Kappetein</surname>
              <given-names>AP</given-names>
            </name>
            <name>
              <surname>Morice</surname>
              <given-names>MC</given-names>
            </name>
            <name>
              <surname>Colombo</surname>
              <given-names>A</given-names>
            </name>
            <name>
              <surname>Dawkins</surname>
              <given-names>K</given-names>
            </name>
            <etal>et al</etal>
          </person-group>
          <article-title>The SYNTAX Score: an angiographic tool grading the complexity of coronary artery disease</article-title>
          <source>EuroIntervention</source>
          <year>2005</year>
          <volume>1</volume>
          <issue>2</issue>
          <fpage>219</fpage>
          <lpage>227</lpage>
          <comment>PMID: 19758907</comment>
        </element-citation>
      </ref>
      <ref id="B5">
        <label>5</label>
        <mixed-citation>5. Serruys PW , Onuma Y , Garg S , Sarno G , van den Brand M , Kappetein AP , et al . Assessment of the SYNTAX score in the Syntax study . EuroIntervention . 2009 ; 5 ( 1 ): 50 - 6 . DOI: 10.4244/eijv5i1a9 </mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Serruys</surname>
              <given-names>PW</given-names>
            </name>
            <name>
              <surname>Onuma</surname>
              <given-names>Y</given-names>
            </name>
            <name>
              <surname>Garg</surname>
              <given-names>S</given-names>
            </name>
            <name>
              <surname>Sarno</surname>
              <given-names>G</given-names>
            </name>
            <name>
              <surname>van den Brand</surname>
              <given-names>M</given-names>
            </name>
            <name>
              <surname>Kappetein</surname>
              <given-names>AP</given-names>
            </name>
            <etal>et al</etal>
          </person-group>
          <article-title>Assessment of the SYNTAX score in the Syntax study</article-title>
          <source>EuroIntervention</source>
          <year>2009</year>
          <volume>5</volume>
          <issue>1</issue>
          <fpage>50</fpage>
          <lpage>56</lpage>
          <issue-id pub-id-type="doi">10.4244/eijv5i1a9</issue-id>
        </element-citation>
      </ref>
      <ref id="B6">
        <label>6</label>
        <mixed-citation>6. Mohr FW , Morice MC , Kappetein AP , Feldman TE , St&#229;hle E , Colombo A , et al . Coronary artery bypass graft surgery versus percutaneous coronary intervention in patients with three-vessel disease and left main coronary disease: 5-year follow-up of the randomised, clinical SYNTAX trial . Lancet . 2013 ; 381 ( 9867 ): 629 - 38 . DOI: 10.1016/S0140-6736(13)60141-5 </mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Mohr</surname>
              <given-names>FW</given-names>
            </name>
            <name>
              <surname>Morice</surname>
              <given-names>MC</given-names>
            </name>
            <name>
              <surname>Kappetein</surname>
              <given-names>AP</given-names>
            </name>
            <name>
              <surname>Feldman</surname>
              <given-names>TE</given-names>
            </name>
            <name>
              <surname>St&#229;hle</surname>
              <given-names>E</given-names>
            </name>
            <name>
              <surname>Colombo</surname>
              <given-names>A</given-names>
            </name>
            <etal>et al</etal>
          </person-group>
          <article-title>Coronary artery bypass graft surgery versus percutaneous coronary intervention in patients with three-vessel disease and left main coronary disease: 5-year follow-up of the randomised, clinical SYNTAX trial</article-title>
          <source>Lancet</source>
          <year>2013</year>
          <volume>381</volume>
          <issue>9867</issue>
          <fpage>629</fpage>
          <lpage>638</lpage>
          <issue-id pub-id-type="doi">10.1016/S0140-6736(13)60141-5</issue-id>
        </element-citation>
      </ref>
      <ref id="B7">
        <label>7</label>
        <mixed-citation>7. Davenport AP , Hyndman KA , Dhaun N , Southan C , Kohan DE , Pollock JS , et al . Endothelin . Pharmacol Rev . 2016 ; 68 ( 2 ): 357 - 418 . DOI: 10.1124/pr.115.011833 </mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Davenport</surname>
              <given-names>AP</given-names>
            </name>
            <name>
              <surname>Hyndman</surname>
              <given-names>KA</given-names>
            </name>
            <name>
              <surname>Dhaun</surname>
              <given-names>N</given-names>
            </name>
            <name>
              <surname>Southan</surname>
              <given-names>C</given-names>
            </name>
            <name>
              <surname>Kohan</surname>
              <given-names>DE</given-names>
            </name>
            <name>
              <surname>Pollock</surname>
              <given-names>JS</given-names>
            </name>
            <etal>et al</etal>
          </person-group>
          <article-title>Endothelin</article-title>
          <source>Pharmacol Rev</source>
          <year>2016</year>
          <volume>68</volume>
          <issue>2</issue>
          <fpage>357</fpage>
          <lpage>418</lpage>
          <issue-id pub-id-type="doi">10.1124/pr.115.011833</issue-id>
        </element-citation>
      </ref>
      <ref id="B8">
        <label>8</label>
        <mixed-citation>8. Kolettis TM , Barton M , Langleben D , Matsumura Y . Endothelin in coronary artery disease and myocardial infarction . Cardiol Rev . 2013 ; 21 ( 5 ): 249 - 56 . DOI: 10.1097/CRD.0b013e318283f65a </mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Kolettis</surname>
              <given-names>TM</given-names>
            </name>
            <name>
              <surname>Barton</surname>
              <given-names>M</given-names>
            </name>
            <name>
              <surname>Langleben</surname>
              <given-names>D</given-names>
            </name>
            <name>
              <surname>Matsumura</surname>
              <given-names>Y</given-names>
            </name>
          </person-group>
          <article-title>Endothelin in coronary artery disease and myocardial infarction</article-title>
          <source>Cardiol Rev</source>
          <year>2013</year>
          <volume>21</volume>
          <issue>5</issue>
          <fpage>249</fpage>
          <lpage>256</lpage>
          <issue-id pub-id-type="doi">10.1097/CRD.0b013e318283f65a</issue-id>
        </element-citation>
      </ref>
      <ref id="B9">
        <label>9</label>
        <mixed-citation>9. L&#252;scher TF , Barton M . Endothelins and endothelin receptor antagonists: therapeutic considerations for a novel class of cardiovascular drugs . Circulation . 2000 ; 102 ( 19 ): 2434 - 40 . DOI: 10.1161/01.cir.102.19.2434 </mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>L&#252;scher</surname>
              <given-names>TF</given-names>
            </name>
            <name>
              <surname>Barton</surname>
              <given-names>M</given-names>
            </name>
          </person-group>
          <article-title>Endothelins and endothelin receptor antagonists: therapeutic considerations for a novel class of cardiovascular drugs</article-title>
          <source>Circulation</source>
          <year>2000</year>
          <volume>102</volume>
          <issue>19</issue>
          <fpage>2434</fpage>
          <lpage>2440</lpage>
          <issue-id pub-id-type="doi">10.1161/01.cir.102.19.2434</issue-id>
        </element-citation>
      </ref>
      <ref id="B10">
        <label>10</label>
        <mixed-citation>10. Perez AL , Grodin JL , Wu Y , Hernandez AF , Butler J , Metra M , et al . Increased mortality with elevated plasma endothelin-1 in acute heart failure: an ASCEND-HF biomarker substudy . Eur J Heart Fail . 2016 ; 18 ( 3 ): 290 - 7 . DOI: 10.1002/ejhf.456 </mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Perez</surname>
              <given-names>AL</given-names>
            </name>
            <name>
              <surname>Grodin</surname>
              <given-names>JL</given-names>
            </name>
            <name>
              <surname>Wu</surname>
              <given-names>Y</given-names>
            </name>
            <name>
              <surname>Hernandez</surname>
              <given-names>AF</given-names>
            </name>
            <name>
              <surname>Butler</surname>
              <given-names>J</given-names>
            </name>
            <name>
              <surname>Metra</surname>
              <given-names>M</given-names>
            </name>
            <etal>et al</etal>
          </person-group>
          <article-title>Increased mortality with elevated plasma endothelin-1 in acute heart failure: an ASCEND-HF biomarker substudy</article-title>
          <source>Eur J Heart Fail</source>
          <year>2016</year>
          <volume>18</volume>
          <issue>3</issue>
          <fpage>290</fpage>
          <lpage>297</lpage>
          <issue-id pub-id-type="doi">10.1002/ejhf.456</issue-id>
        </element-citation>
      </ref>
      <ref id="B11">
        <label>11</label>
        <mixed-citation>11. Eitel I , Nowak M , Stehl C , Adams V , Fuernau G , Hildebrand L , et al . Endothelin-1 release in acute myocardial infarction as a predictor of long-term prognosis and no-reflow assessed by contrast-enhanced magnetic resonance imaging . Am Heart J . 2010 ; 159 ( 5 ): 882 - 90 .DOI: 10.1016/j.ahj.2010.02.019 </mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Eitel</surname>
              <given-names>I</given-names>
            </name>
            <name>
              <surname>Nowak</surname>
              <given-names>M</given-names>
            </name>
            <name>
              <surname>Stehl</surname>
              <given-names>C</given-names>
            </name>
            <name>
              <surname>Adams</surname>
              <given-names>V</given-names>
            </name>
            <name>
              <surname>Fuernau</surname>
              <given-names>G</given-names>
            </name>
            <name>
              <surname>Hildebrand</surname>
              <given-names>L</given-names>
            </name>
            <etal>et al</etal>
          </person-group>
          <article-title>Endothelin-1 release in acute myocardial infarction as a predictor of long-term prognosis and no-reflow assessed by contrast-enhanced magnetic resonance imaging</article-title>
          <source>Am Heart J</source>
          <year>2010</year>
          <volume>159</volume>
          <issue>5</issue>
          <fpage>882</fpage>
          <lpage>890</lpage>
          <issue-id pub-id-type="doi">10.1016/j.ahj.2010.02.019</issue-id>
        </element-citation>
      </ref>
      <ref id="B12">
        <label>12</label>
        <mixed-citation>12. Omland T , Lie RT , Aakvaag A , Aarsland T , Dickstein K ( 1994 ) Plasma endothelin determination as a prognostic indicator of 1-year mortality after acute myocardial infarction . Circulation . 1994 ; 89 ( 4 ): 1573 - 9 .DOI: 10.1161/01.cir.89.4.1573 </mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Omland</surname>
              <given-names>T</given-names>
            </name>
            <name>
              <surname>Lie</surname>
              <given-names>RT</given-names>
            </name>
            <name>
              <surname>Aakvaag</surname>
              <given-names>A</given-names>
            </name>
            <name>
              <surname>Aarsland</surname>
              <given-names>T</given-names>
            </name>
            <name>
              <surname>Dickstein</surname>
              <given-names>K</given-names>
            </name>
          </person-group>
          <year>1994</year>
          <article-title>Plasma endothelin determination as a prognostic indicator of 1-year mortality after acute myocardial infarction</article-title>
          <source>Circulation . 1994</source>
          <volume>89</volume>
          <issue>4</issue>
          <fpage>1573</fpage>
          <lpage>1579</lpage>
          <issue-id pub-id-type="doi">10.1161/01.cir.89.4.1573</issue-id>
        </element-citation>
      </ref>
      <ref id="B13">
        <label>13</label>
        <mixed-citation>13. Katayama T , Yano K , Nakashima H , Takagi C , Honda Y , Suzuki S , et al . Clinical significance of acute-phase endothelin-1 in acute myocardial infarction patients treated with direct coronary angioplasty . Circ J . 2005 ; 69 ( 6 ): 654 - 8 . DOI: 10.1253/circj.69.654 </mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Katayama</surname>
              <given-names>T</given-names>
            </name>
            <name>
              <surname>Yano</surname>
              <given-names>K</given-names>
            </name>
            <name>
              <surname>Nakashima</surname>
              <given-names>H</given-names>
            </name>
            <name>
              <surname>Takagi</surname>
              <given-names>C</given-names>
            </name>
            <name>
              <surname>Honda</surname>
              <given-names>Y</given-names>
            </name>
            <name>
              <surname>Suzuki</surname>
              <given-names>S</given-names>
            </name>
            <etal>et al</etal>
          </person-group>
          <article-title>Clinical significance of acute-phase endothelin-1 in acute myocardial infarction patients treated with direct coronary angioplasty</article-title>
          <source>Circ J</source>
          <year>2005</year>
          <volume>69</volume>
          <issue>6</issue>
          <fpage>654</fpage>
          <lpage>658</lpage>
          <issue-id pub-id-type="doi">10.1253/circj.69.654</issue-id>
        </element-citation>
      </ref>
      <ref id="B14">
        <label>14</label>
        <mixed-citation>14. Yip HK , Wu CJ , Chang HW , Yang CH , Yu TH , Chen YH , et al . Prognostic value of circulating levels of endothelin-1 in patients after acute myocardial infarction undergoing primary coronary angioplasty . Chest . 2005 ; 127 ( 5 ): 491 - 7 . DOI: 10.1378/chest.127.5.1491 </mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Yip</surname>
              <given-names>HK</given-names>
            </name>
            <name>
              <surname>Wu</surname>
              <given-names>CJ</given-names>
            </name>
            <name>
              <surname>Chang</surname>
              <given-names>HW</given-names>
            </name>
            <name>
              <surname>Yang</surname>
              <given-names>CH</given-names>
            </name>
            <name>
              <surname>Yu</surname>
              <given-names>TH</given-names>
            </name>
            <name>
              <surname>Chen</surname>
              <given-names>YH</given-names>
            </name>
            <etal>et al</etal>
          </person-group>
          <article-title>Prognostic value of circulating levels of endothelin-1 in patients after acute myocardial infarction undergoing primary coronary angioplasty</article-title>
          <source>Chest</source>
          <year>2005</year>
          <volume>127</volume>
          <issue>5</issue>
          <fpage>491</fpage>
          <lpage>497</lpage>
          <issue-id pub-id-type="doi">10.1378/chest.127.5.1491</issue-id>
        </element-citation>
      </ref>
      <ref id="B15">
        <label>15</label>
        <mixed-citation>15. Zhou BY , Gao XY , Zhao X , Qing P , Zhu CG , Wu NQ , et al. Guo YL , Gao Y , Liu G , Dong Q , Li JJ ( 2018 ) Predictive value of big endothelin-1 on outcomes in patients with myocardial infarction younger than 35 years old . Per Med . 2018 ; 15 ( 1 ): 25 - 33 . DOI: 10.2217/pme-2017-0044 </mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Zhou</surname>
              <given-names>BY</given-names>
            </name>
            <name>
              <surname>Gao</surname>
              <given-names>XY</given-names>
            </name>
            <name>
              <surname>Zhao</surname>
              <given-names>X</given-names>
            </name>
            <name>
              <surname>Qing</surname>
              <given-names>P</given-names>
            </name>
            <name>
              <surname>Zhu</surname>
              <given-names>CG</given-names>
            </name>
            <name>
              <surname>Wu</surname>
              <given-names>NQ</given-names>
            </name>
            <name>
              <surname>et al. Guo</surname>
              <given-names>YL</given-names>
            </name>
            <name>
              <surname>Gao</surname>
              <given-names>Y</given-names>
            </name>
            <name>
              <surname>Liu</surname>
              <given-names>G</given-names>
            </name>
            <name>
              <surname>Dong</surname>
              <given-names>Q</given-names>
            </name>
            <name>
              <surname>Li</surname>
              <given-names>JJ</given-names>
            </name>
          </person-group>
          <year>2018</year>
          <article-title>Predictive value of big endothelin-1 on outcomes in patients with myocardial infarction younger than 35 years old</article-title>
          <source>Per Med . 2018</source>
          <volume>15</volume>
          <issue>1</issue>
          <fpage>25</fpage>
          <lpage>33</lpage>
          <issue-id pub-id-type="doi">10.2217/pme-2017-0044</issue-id>
        </element-citation>
      </ref>
      <ref id="B16">
        <label>16</label>
        <mixed-citation>16. Wang Y , Tang Y , Zou Y , Wang D , Zhu L , Tian T , et al . Plasma level of big endothelin-1 predicts the prognosis in patients with hypertrophic cardiomyopathy . Int J Cardiol . 2017 ; 243 : 283 - 9 . DOI: 10.1016/j.ijcard.2017.03.162 </mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Wang</surname>
              <given-names>Y</given-names>
            </name>
            <name>
              <surname>Tang</surname>
              <given-names>Y</given-names>
            </name>
            <name>
              <surname>Zou</surname>
              <given-names>Y</given-names>
            </name>
            <name>
              <surname>Wang</surname>
              <given-names>D</given-names>
            </name>
            <name>
              <surname>Zhu</surname>
              <given-names>L</given-names>
            </name>
            <name>
              <surname>Tian</surname>
              <given-names>T</given-names>
            </name>
            <etal>et al</etal>
          </person-group>
          <article-title>Plasma level of big endothelin-1 predicts the prognosis in patients with hypertrophic cardiomyopathy</article-title>
          <source>Int J Cardiol</source>
          <year>2017</year>
          <volume>243</volume>
          <fpage>283</fpage>
          <lpage>289</lpage>
          <issue-id pub-id-type="doi">10.1016/j.ijcard.2017.03.162</issue-id>
        </element-citation>
      </ref>
      <ref id="B17">
        <label>17</label>
        <mixed-citation>17. Thygesen K , Alpert JS , Jaffe AS , Chaitman BR , Bax JJ , Morrow DA , et al . Fourth Universal Definition of Myocardial Infarction . Circulation . 2018 ; 138 ( 20 ): e618 - 51 . DOI: 10.1016/j.jacc.2018.08.1038 </mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Thygesen</surname>
              <given-names>K</given-names>
            </name>
            <name>
              <surname>Alpert</surname>
              <given-names>JS</given-names>
            </name>
            <name>
              <surname>Jaffe</surname>
              <given-names>AS</given-names>
            </name>
            <name>
              <surname>Chaitman</surname>
              <given-names>BR</given-names>
            </name>
            <name>
              <surname>Bax</surname>
              <given-names>JJ</given-names>
            </name>
            <name>
              <surname>Morrow</surname>
              <given-names>DA</given-names>
            </name>
            <etal>et al</etal>
          </person-group>
          <article-title>Fourth Universal Definition of Myocardial Infarction</article-title>
          <source>Circulation</source>
          <year>2018</year>
          <volume>138</volume>
          <issue>20</issue>
          <fpage>e618</fpage>
          <lpage>e651</lpage>
          <issue-id pub-id-type="doi">10.1016/j.jacc.2018.08.1038</issue-id>
        </element-citation>
      </ref>
      <ref id="B18">
        <label>18</label>
        <mixed-citation>18. Hickey KA , Rubanyi G , Paul RJ , Highsmith RF . Characterization of a coronary vasoconstrictor produced by cultured endothelial cells . Am J Physiol . 1985 ; 248 ( 5 ): C550 - 6 . DOI: 10.1152/ajpcell.1985.248.5.C550 </mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Hickey</surname>
              <given-names>KA</given-names>
            </name>
            <name>
              <surname>Rubanyi</surname>
              <given-names>G</given-names>
            </name>
            <name>
              <surname>Paul</surname>
              <given-names>RJ</given-names>
            </name>
            <name>
              <surname>Highsmith</surname>
              <given-names>RF</given-names>
            </name>
          </person-group>
          <article-title>Characterization of a coronary vasoconstrictor produced by cultured endothelial cells</article-title>
          <source>Am J Physiol</source>
          <year>1985</year>
          <volume>248</volume>
          <issue>5</issue>
          <fpage>C550</fpage>
          <lpage>C556</lpage>
          <issue-id pub-id-type="doi">10.1152/ajpcell.1985.248.5.C550</issue-id>
        </element-citation>
      </ref>
      <ref id="B19">
        <label>19</label>
        <mixed-citation>19. Mayyas F , Al-Jarrah M , Ibrahim K , Mfady D , Van Wagoner DR . The significance of circulating endothelin-1 as a predictor of coronary artery disease status and clinical outcomes following coronary artery catheterization . Cardiovasc Pathol . 2015 ; 24 ( 1 ): 19 - 25 . DOI: 10.1016/j.carpath.2014.08.004 </mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Mayyas</surname>
              <given-names>F</given-names>
            </name>
            <name>
              <surname>Al-Jarrah</surname>
              <given-names>M</given-names>
            </name>
            <name>
              <surname>Ibrahim</surname>
              <given-names>K</given-names>
            </name>
            <name>
              <surname>Mfady</surname>
              <given-names>D</given-names>
            </name>
            <name>
              <surname>Van Wagoner</surname>
              <given-names>DR</given-names>
            </name>
          </person-group>
          <article-title>The significance of circulating endothelin-1 as a predictor of coronary artery disease status and clinical outcomes following coronary artery catheterization</article-title>
          <source>Cardiovasc Pathol</source>
          <year>2015</year>
          <volume>24</volume>
          <issue>1</issue>
          <fpage>19</fpage>
          <lpage>25</lpage>
          <issue-id pub-id-type="doi">10.1016/j.carpath.2014.08.004</issue-id>
        </element-citation>
      </ref>
      <ref id="B20">
        <label>20</label>
        <mixed-citation>20. Tsutamoto T , Wada A , Hayashi M , Tsutsui T , Maeda K , Ohnishi M , et al . Relationship between transcardiac gradient of endothelin-1 and left ventricular remodelling in patients with first anterior myocardial infarction . Eur Heart J . 2003 ; 24 ( 4 ): 346 - 55 . DOI: 10.1016/s0195-668x(02)00420-7 </mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Tsutamoto</surname>
              <given-names>T</given-names>
            </name>
            <name>
              <surname>Wada</surname>
              <given-names>A</given-names>
            </name>
            <name>
              <surname>Hayashi</surname>
              <given-names>M</given-names>
            </name>
            <name>
              <surname>Tsutsui</surname>
              <given-names>T</given-names>
            </name>
            <name>
              <surname>Maeda</surname>
              <given-names>K</given-names>
            </name>
            <name>
              <surname>Ohnishi</surname>
              <given-names>M</given-names>
            </name>
            <etal>et al</etal>
          </person-group>
          <article-title>Relationship between transcardiac gradient of endothelin-1 and left ventricular remodelling in patients with first anterior myocardial infarction</article-title>
          <source>Eur Heart J</source>
          <year>2003</year>
          <volume>24</volume>
          <issue>4</issue>
          <fpage>346</fpage>
          <lpage>355</lpage>
          <issue-id pub-id-type="doi">10.1016/s0195-668x(02)00420-7</issue-id>
        </element-citation>
      </ref>
      <ref id="B21">
        <label>21</label>
        <mixed-citation>21. Chen Y , Li JX , Song Y , Xu JJ , Tang XF , Jiang L , et al . Plasma big endothelin-1 and stent thrombosis: An observational study in patients undergoing percutaneous coronary intervention in China . Thromb Res . 2017 ; 159 : 5 - 12 . DOI: 10.1016/j.thromres.2017.09.013 </mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Chen</surname>
              <given-names>Y</given-names>
            </name>
            <name>
              <surname>Li</surname>
              <given-names>JX</given-names>
            </name>
            <name>
              <surname>Song</surname>
              <given-names>Y</given-names>
            </name>
            <name>
              <surname>Xu</surname>
              <given-names>JJ</given-names>
            </name>
            <name>
              <surname>Tang</surname>
              <given-names>XF</given-names>
            </name>
            <name>
              <surname>Jiang</surname>
              <given-names>L</given-names>
            </name>
            <etal>et al</etal>
          </person-group>
          <article-title>Plasma big endothelin-1 and stent thrombosis: An observational study in patients undergoing percutaneous coronary intervention in China</article-title>
          <source>Thromb Res</source>
          <year>2017</year>
          <volume>159</volume>
          <fpage>5</fpage>
          <lpage>12</lpage>
          <issue-id pub-id-type="doi">10.1016/j.thromres.2017.09.013</issue-id>
        </element-citation>
      </ref>
      <ref id="B22">
        <label>22</label>
        <mixed-citation>22. Kanaya AM , Barrett-Connor E , Wassel Fyr CL . Endothelin-1 and prevalent coronary heart disease in older men and women (the Rancho Bernardo Study) . Am J Cardiol . 2007 ; 99 ( 4 ): 486 - 90 . DOI: 10.1016/j.amjcard.2006.09.096 </mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Kanaya</surname>
              <given-names>AM</given-names>
            </name>
            <name>
              <surname>Barrett-Connor</surname>
              <given-names>E</given-names>
            </name>
            <name>
              <surname>Wassel Fyr</surname>
              <given-names>CL</given-names>
            </name>
          </person-group>
          <article-title>Endothelin-1 and prevalent coronary heart disease in older men and women (the Rancho Bernardo Study)</article-title>
          <source>Am J Cardiol</source>
          <year>2007</year>
          <volume>99</volume>
          <issue>4</issue>
          <fpage>486</fpage>
          <lpage>490</lpage>
          <issue-id pub-id-type="doi">10.1016/j.amjcard.2006.09.096</issue-id>
        </element-citation>
      </ref>
      <ref id="B23">
        <label>23</label>
        <mixed-citation>23. Wang F , Li T , Cong X , Hou Z , Lu B , Zhou Z , et al . Association between circulating big endothelin-1 and noncalcified or mixed coronary atherosclerotic plaques . Coron Artery Dis . 2019 ; 30 ( 6 ): 461 - 6 . DOI: 10.1097/MCA.0000000000000752 </mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Wang</surname>
              <given-names>F</given-names>
            </name>
            <name>
              <surname>Li</surname>
              <given-names>T</given-names>
            </name>
            <name>
              <surname>Cong</surname>
              <given-names>X</given-names>
            </name>
            <name>
              <surname>Hou</surname>
              <given-names>Z</given-names>
            </name>
            <name>
              <surname>Lu</surname>
              <given-names>B</given-names>
            </name>
            <name>
              <surname>Zhou</surname>
              <given-names>Z</given-names>
            </name>
            <etal>et al</etal>
          </person-group>
          <article-title>Association between circulating big endothelin-1 and noncalcified or mixed coronary atherosclerotic plaques</article-title>
          <source>Coron Artery Dis</source>
          <year>2019</year>
          <volume>30</volume>
          <issue>6</issue>
          <fpage>461</fpage>
          <lpage>466</lpage>
          <issue-id pub-id-type="doi">10.1097/MCA.0000000000000752</issue-id>
        </element-citation>
      </ref>
      <ref id="B24">
        <label>24</label>
        <mixed-citation>24. Wang F , Li T , Cong X , Hou Z , Lu B , Zhou Z , Chen X . The Value of Big Endothelin-1 in the Assessment of the Severity of Coronary Artery Calcification . Clin Appl Thromb Hemost . 2018 ; 24 ( 7 ): 1042 - 9 . DOI: 10.1177/1076029618764846 </mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Wang</surname>
              <given-names>F</given-names>
            </name>
            <name>
              <surname>Li</surname>
              <given-names>T</given-names>
            </name>
            <name>
              <surname>Cong</surname>
              <given-names>X</given-names>
            </name>
            <name>
              <surname>Hou</surname>
              <given-names>Z</given-names>
            </name>
            <name>
              <surname>Lu</surname>
              <given-names>B</given-names>
            </name>
            <name>
              <surname>Zhou</surname>
              <given-names>Z</given-names>
            </name>
            <name>
              <surname>Chen</surname>
              <given-names>X</given-names>
            </name>
          </person-group>
          <article-title>The Value of Big Endothelin-1 in the Assessment of the Severity of Coronary Artery Calcification</article-title>
          <source>Clin Appl Thromb Hemost</source>
          <year>2018</year>
          <volume>24</volume>
          <issue>7</issue>
          <fpage>1042</fpage>
          <lpage>1049</lpage>
          <issue-id pub-id-type="doi">10.1177/1076029618764846</issue-id>
        </element-citation>
      </ref>
      <ref id="B25">
        <label>25</label>
        <mixed-citation>25. Chen J , Chen MH , Guo YL , Zhu CG , Xu RX , Dong Q , Li JJ . Plasma big endothelin-1 level and the severity of new-onset stable coronary artery disease . J Atheroscler Thromb . 2015 ; 22 ( 2 ): 126 - 35 . DOI: 10.5551/jat.26401 </mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Chen</surname>
              <given-names>J</given-names>
            </name>
            <name>
              <surname>Chen</surname>
              <given-names>MH</given-names>
            </name>
            <name>
              <surname>Guo</surname>
              <given-names>YL</given-names>
            </name>
            <name>
              <surname>Zhu</surname>
              <given-names>CG</given-names>
            </name>
            <name>
              <surname>Xu</surname>
              <given-names>RX</given-names>
            </name>
            <name>
              <surname>Dong</surname>
              <given-names>Q</given-names>
            </name>
            <name>
              <surname>Li</surname>
              <given-names>JJ</given-names>
            </name>
          </person-group>
          <article-title>Plasma big endothelin-1 level and the severity of new-onset stable coronary artery disease</article-title>
          <source>J Atheroscler Thromb</source>
          <year>2015</year>
          <volume>22</volume>
          <issue>2</issue>
          <fpage>126</fpage>
          <lpage>135</lpage>
          <issue-id pub-id-type="doi">10.5551/jat.26401</issue-id>
        </element-citation>
      </ref>
      <ref id="B26">
        <label>26</label>
        <mixed-citation>26. Dobarro D , G&#243;mez-Rub&#237;n MC , Sanchez-Recalde A , Moreno R , Galeote G , Jimenez-Valero S , et al . Current pharmacological approach to restore endothelial dysfunction . Cardiovasc Hematol Agents Med Chem . 2009 ; 7 ( 3 ): 212 - 22 . DOI: 10.2174/187152509789105480 </mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Dobarro</surname>
              <given-names>D</given-names>
            </name>
            <name>
              <surname>G&#243;mez-Rub&#237;n</surname>
              <given-names>MC</given-names>
            </name>
            <name>
              <surname>Sanchez-Recalde</surname>
              <given-names>A</given-names>
            </name>
            <name>
              <surname>Moreno</surname>
              <given-names>R</given-names>
            </name>
            <name>
              <surname>Galeote</surname>
              <given-names>G</given-names>
            </name>
            <name>
              <surname>Jimenez-Valero</surname>
              <given-names>S</given-names>
            </name>
            <etal>et al</etal>
          </person-group>
          <article-title>Current pharmacological approach to restore endothelial dysfunction</article-title>
          <source>Cardiovasc Hematol Agents Med Chem</source>
          <year>2009</year>
          <volume>7</volume>
          <issue>3</issue>
          <fpage>212</fpage>
          <lpage>222</lpage>
          <issue-id pub-id-type="doi">10.2174/187152509789105480</issue-id>
        </element-citation>
      </ref>
      <ref id="B27">
        <label>27</label>
        <mixed-citation>27. Weil BR , Westby CM , Greiner JJ , Stauffer BL , DeSouza CA . Elevated endothelin-1 vasoconstrictor tone in prehypertensive adults . Can J Cardiol . 2012 ; 28 ( 3 ): 347 - 53 . DOI: 10.1016/j.cjca.2011.11.006 </mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Weil</surname>
              <given-names>BR</given-names>
            </name>
            <name>
              <surname>Westby</surname>
              <given-names>CM</given-names>
            </name>
            <name>
              <surname>Greiner</surname>
              <given-names>JJ</given-names>
            </name>
            <name>
              <surname>Stauffer</surname>
              <given-names>BL</given-names>
            </name>
            <name>
              <surname>DeSouza</surname>
              <given-names>CA</given-names>
            </name>
          </person-group>
          <article-title>Elevated endothelin-1 vasoconstrictor tone in prehypertensive adults</article-title>
          <source>Can J Cardiol</source>
          <year>2012</year>
          <volume>28</volume>
          <issue>3</issue>
          <fpage>347</fpage>
          <lpage>353</lpage>
          <issue-id pub-id-type="doi">10.1016/j.cjca.2011.11.006</issue-id>
        </element-citation>
      </ref>
      <ref id="B28">
        <label>28</label>
        <mixed-citation>28. Lerman A , Zeiher AM . Endothelial function: cardiac events . Circulation . 2005 ; 111 ( 3 ): 363 - 8 . DOI: 10.1161/01.CIR.0000153339.27064.14 </mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Lerman</surname>
              <given-names>A</given-names>
            </name>
            <name>
              <surname>Zeiher</surname>
              <given-names>AM</given-names>
            </name>
          </person-group>
          <article-title>Endothelial function: cardiac events</article-title>
          <source>Circulation</source>
          <year>2005</year>
          <volume>111</volume>
          <issue>3</issue>
          <fpage>363</fpage>
          <lpage>368</lpage>
          <issue-id pub-id-type="doi">10.1161/01.CIR.0000153339.27064.14</issue-id>
        </element-citation>
      </ref>
      <ref id="B29">
        <label>29</label>
        <mixed-citation>29. Khimji AK , Rockey DC ( 2010 ) Endothelin--biology and disease . Cell Signal . 2010 ; 22 ( 11 ): 1615 - 25 . DOI: 10.1016/j.cellsig.2010.05.002 </mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Khimji</surname>
              <given-names>AK</given-names>
            </name>
            <name>
              <surname>Rockey</surname>
              <given-names>DC</given-names>
            </name>
          </person-group>
          <year>2010</year>
          <article-title>Endothelin--biology and disease</article-title>
          <source>Cell Signal . 2010</source>
          <volume>22</volume>
          <issue>11</issue>
          <fpage>1615</fpage>
          <lpage>1625</lpage>
          <issue-id pub-id-type="doi">10.1016/j.cellsig.2010.05.002</issue-id>
        </element-citation>
      </ref>
      <ref id="B30">
        <label>30</label>
        <mixed-citation>30. Hansson GK . Inflammation, atherosclerosis, and coronary artery disease . N Engl J Med . 2005 ; 352 ( 16 ): 1685 - 95 . DOI: 10.1056/NEJMra043430 </mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Hansson</surname>
              <given-names>GK</given-names>
            </name>
          </person-group>
          <article-title>Inflammation, atherosclerosis, and coronary artery disease</article-title>
          <source>N Engl J Med</source>
          <year>2005</year>
          <volume>352</volume>
          <issue>16</issue>
          <fpage>1685</fpage>
          <lpage>1695</lpage>
          <issue-id pub-id-type="doi">10.1056/NEJMra043430</issue-id>
        </element-citation>
      </ref>
      <ref id="B31">
        <label>31</label>
        <mixed-citation>31. Sessa WC , Kaw S , Hecker M , Vane JR . The biosynthesis of endothelin-1 by human polymorphonuclear leukocytes . Biochem Biophys Res Commun . 1991 ; 174 ( 2 ): 613 - 8 . <ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1016/0006-291X(91)91461-K">https://doi.org/10.1016/0006-291X(91)91461-K</ext-link> </mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Sessa</surname>
              <given-names>WC</given-names>
            </name>
            <name>
              <surname>Kaw</surname>
              <given-names>S</given-names>
            </name>
            <name>
              <surname>Hecker</surname>
              <given-names>M</given-names>
            </name>
            <name>
              <surname>Vane</surname>
              <given-names>JR</given-names>
            </name>
          </person-group>
          <article-title>The biosynthesis of endothelin-1 by human polymorphonuclear leukocytes</article-title>
          <source>Biochem Biophys Res Commun</source>
          <year>1991</year>
          <volume>174</volume>
          <issue>2</issue>
          <fpage>613</fpage>
          <lpage>618</lpage>
          <comment>
            <ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1016/0006-291X(91)91461-K">https://doi.org/10.1016/0006-291X(91)91461-K</ext-link>
          </comment>
        </element-citation>
      </ref>
      <ref id="B32">
        <label>32</label>
        <mixed-citation>32. Ehrenreich H , Anderson RW , Fox CH , Rieckmann P , Hoffman GS , Travis WD , et al . Endothelins, peptides with potent vasoactive properties, are produced by human macrophages . J Exp Med . 1990 ; 172 ( 6 ): 1741 - 8 . DOI: 10.1084/jem.172.6.1741 </mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Ehrenreich</surname>
              <given-names>H</given-names>
            </name>
            <name>
              <surname>Anderson</surname>
              <given-names>RW</given-names>
            </name>
            <name>
              <surname>Fox</surname>
              <given-names>CH</given-names>
            </name>
            <name>
              <surname>Rieckmann</surname>
              <given-names>P</given-names>
            </name>
            <name>
              <surname>Hoffman</surname>
              <given-names>GS</given-names>
            </name>
            <name>
              <surname>Travis</surname>
              <given-names>WD</given-names>
            </name>
            <etal>et al</etal>
          </person-group>
          <article-title>Endothelins, peptides with potent vasoactive properties, are produced by human macrophages</article-title>
          <source>J Exp Med</source>
          <year>1990</year>
          <volume>172</volume>
          <issue>6</issue>
          <fpage>1741</fpage>
          <lpage>1748</lpage>
          <issue-id pub-id-type="doi">10.1084/jem.172.6.1741</issue-id>
        </element-citation>
      </ref>
      <ref id="B33">
        <label>33</label>
        <mixed-citation>33. L&#243;pez Farr&#233; A , Riesco A , Espinosa G , Digiuni E , Cernadas MR , Alvarez V , et al . Effect of endothelin-1 on neutrophil adhesion to endothelial cells and perfused heart . Circulation . 1993 ; 88 ( 3 ): 1166 - 71 . DOI: 10.1161/01.cir.88.3.1166 </mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>L&#243;pez Farr&#233;</surname>
              <given-names>A</given-names>
            </name>
            <name>
              <surname>Riesco</surname>
              <given-names>A</given-names>
            </name>
            <name>
              <surname>Espinosa</surname>
              <given-names>G</given-names>
            </name>
            <name>
              <surname>Digiuni</surname>
              <given-names>E</given-names>
            </name>
            <name>
              <surname>Cernadas</surname>
              <given-names>MR</given-names>
            </name>
            <name>
              <surname>Alvarez</surname>
              <given-names>V</given-names>
            </name>
            <etal>et al</etal>
          </person-group>
          <article-title>Effect of endothelin-1 on neutrophil adhesion to endothelial cells and perfused heart</article-title>
          <source>Circulation</source>
          <year>1993</year>
          <volume>88</volume>
          <issue>3</issue>
          <fpage>1166</fpage>
          <lpage>1171</lpage>
          <issue-id pub-id-type="doi">10.1161/01.cir.88.3.1166</issue-id>
        </element-citation>
      </ref>
      <ref id="B34">
        <label>34</label>
        <mixed-citation>34. Li MW , Mian MO , Barhoumi T , Rehman A , Mann K , Paradis P , et al . Endothelin-1 overexpression exacerbates atherosclerosis and induces aortic aneurysms in apolipoprotein E knockout mice . Arterioscler Thromb Vasc Biol . 2013 ; 33 ( 10 ): 2306 - 15 . DOI: 10.1161/ATVBAHA.113.302028 </mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Li</surname>
              <given-names>MW</given-names>
            </name>
            <name>
              <surname>Mian</surname>
              <given-names>MO</given-names>
            </name>
            <name>
              <surname>Barhoumi</surname>
              <given-names>T</given-names>
            </name>
            <name>
              <surname>Rehman</surname>
              <given-names>A</given-names>
            </name>
            <name>
              <surname>Mann</surname>
              <given-names>K</given-names>
            </name>
            <name>
              <surname>Paradis</surname>
              <given-names>P</given-names>
            </name>
            <etal>et al</etal>
          </person-group>
          <article-title>Endothelin-1 overexpression exacerbates atherosclerosis and induces aortic aneurysms in apolipoprotein E knockout mice</article-title>
          <source>Arterioscler Thromb Vasc Biol</source>
          <year>2013</year>
          <volume>33</volume>
          <issue>10</issue>
          <fpage>2306</fpage>
          <lpage>2315</lpage>
          <issue-id pub-id-type="doi">10.1161/ATVBAHA.113.302028</issue-id>
        </element-citation>
      </ref>
      <ref id="B35">
        <label>35</label>
        <mixed-citation>35. Kiechl S , Schett G , Schwaiger J , Seppi K , Eder P , Egger G , et al . Soluble receptor activator of nuclear factor-kappa B ligand and risk for cardiovascular disease . Circulation . 2007 ; 116 ( 4 ): 385 - 91 . DOI: 10.1161/CIRCULATIONAHA.106.686774 </mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Kiechl</surname>
              <given-names>S</given-names>
            </name>
            <name>
              <surname>Schett</surname>
              <given-names>G</given-names>
            </name>
            <name>
              <surname>Schwaiger</surname>
              <given-names>J</given-names>
            </name>
            <name>
              <surname>Seppi</surname>
              <given-names>K</given-names>
            </name>
            <name>
              <surname>Eder</surname>
              <given-names>P</given-names>
            </name>
            <name>
              <surname>Egger</surname>
              <given-names>G</given-names>
            </name>
            <etal>et al</etal>
          </person-group>
          <article-title>Soluble receptor activator of nuclear factor-kappa B ligand and risk for cardiovascular disease</article-title>
          <source>Circulation</source>
          <year>2007</year>
          <volume>116</volume>
          <issue>4</issue>
          <fpage>385</fpage>
          <lpage>391</lpage>
          <issue-id pub-id-type="doi">10.1161/CIRCULATIONAHA.106.686774</issue-id>
        </element-citation>
      </ref>
      <ref id="B36">
        <label>36</label>
        <mixed-citation>36. Fan Y , Li S , Li XL , Lin XL , Zhu CG , Xu RX , et al . Plasma endothelin-1 level as a predictor for poor collaterals in patients with &#8805;95% coronary chronic occlusion . Thromb Res . 2016 ; 142 : 21 - 5 . DOI: 10.1016/j.thromres.2016.04.007 </mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Fan</surname>
              <given-names>Y</given-names>
            </name>
            <name>
              <surname>Li</surname>
              <given-names>S</given-names>
            </name>
            <name>
              <surname>Li</surname>
              <given-names>XL</given-names>
            </name>
            <name>
              <surname>Lin</surname>
              <given-names>XL</given-names>
            </name>
            <name>
              <surname>Zhu</surname>
              <given-names>CG</given-names>
            </name>
            <name>
              <surname>Xu</surname>
              <given-names>RX</given-names>
            </name>
            <etal>et al</etal>
          </person-group>
          <article-title>Plasma endothelin-1 level as a predictor for poor collaterals in patients with &#8805;95% coronary chronic occlusion</article-title>
          <source>Thromb Res</source>
          <year>2016</year>
          <volume>142</volume>
          <fpage>21</fpage>
          <lpage>25</lpage>
          <issue-id pub-id-type="doi">10.1016/j.thromres.2016.04.007</issue-id>
        </element-citation>
      </ref>
      <ref id="B37">
        <label>37</label>
        <mixed-citation>37. Halim A , Kanayama N , el Maradny E , Maehara K , Masahiko H , Terao T . Endothelin-1 increased immunoreactive von Willebrand factor in endothelial cells and induced micro thrombosis in rats . Thromb Res . 1994 ; 76 ( 1 ): 71 - 8 . DOI: 10.1016/0049-3848(94)90208-9 </mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Halim</surname>
              <given-names>A</given-names>
            </name>
            <name>
              <surname>Kanayama</surname>
              <given-names>N</given-names>
            </name>
            <name>
              <surname>el Maradny</surname>
              <given-names>E</given-names>
            </name>
            <name>
              <surname>Maehara</surname>
              <given-names>K</given-names>
            </name>
            <name>
              <surname>Masahiko</surname>
              <given-names>H</given-names>
            </name>
            <name>
              <surname>Terao</surname>
              <given-names>T</given-names>
            </name>
          </person-group>
          <article-title>Endothelin-1 increased immunoreactive von Willebrand factor in endothelial cells and induced micro thrombosis in rats</article-title>
          <source>Thromb Res</source>
          <year>1994</year>
          <volume>76</volume>
          <issue>1</issue>
          <fpage>71</fpage>
          <lpage>78</lpage>
          <issue-id pub-id-type="doi">10.1016/0049-3848(94)90208-9</issue-id>
        </element-citation>
      </ref>
      <ref id="B38">
        <label>38</label>
        <mixed-citation>38. Reriani M , Raichlin E , Prasad A , Mathew V , Pumper GM , Nelson RE , et al . Long-term administration of endothelin receptor antagonist improves coronary endothelial function in patients with early atherosclerosis . Circulation . 2010 ; 122 ( 10 ): 958 - 66 . DOI: 10.1161/CIRCULATIONAHA.110.967406 </mixed-citation>
        <element-citation publication-type="journal">
          <person-group person-group-type="author">
            <name>
              <surname>Reriani</surname>
              <given-names>M</given-names>
            </name>
            <name>
              <surname>Raichlin</surname>
              <given-names>E</given-names>
            </name>
            <name>
              <surname>Prasad</surname>
              <given-names>A</given-names>
            </name>
            <name>
              <surname>Mathew</surname>
              <given-names>V</given-names>
            </name>
            <name>
              <surname>Pumper</surname>
              <given-names>GM</given-names>
            </name>
            <name>
              <surname>Nelson</surname>
              <given-names>RE</given-names>
            </name>
            <etal>et al</etal>
          </person-group>
          <article-title>Long-term administration of endothelin receptor antagonist improves coronary endothelial function in patients with early atherosclerosis</article-title>
          <source>Circulation</source>
          <year>2010</year>
          <volume>122</volume>
          <issue>10</issue>
          <fpage>958</fpage>
          <lpage>966</lpage>
          <issue-id pub-id-type="doi">10.1161/CIRCULATIONAHA.110.967406</issue-id>
        </element-citation>
      </ref>
    </ref-list>
    <fn-group>
      <fn fn-type="other">
        <p>Vincula&#231;&#227;o acad&#234;mica</p>
        <p>N&#227;o h&#225; vincula&#231;&#227;o deste estudo a programas de p&#243;s-gradua&#231;&#227;o.</p>
      </fn>
      <fn fn-type="other">
        <label/>
        <p>Aprova&#231;&#227;o &#233;tica e consentimento informado</p>
        <p>Este estudo foi aprovado pelo Comit&#234; de &#201;tica do Fuwai Hospital sob o n&#250;mero de protocolo 2017-1203. Todos os procedimentos envolvidos nesse estudo est&#227;o de acordo com a Declara&#231;&#227;o de Helsinki de 1975, atualizada em 2013. O consentimento informado foi obtido de todos os participantes inclu&#237;dos no estudo.</p>
      </fn>
      <fn id="fn_ast1">
        <label> * </label>
        <p>Material suplementar</p>
      </fn>
      <fn id="fn6">
        <label/>
        <p>Para informa&#231;&#227;o adicional, por favor, clique aqui.</p>
      </fn>
    </fn-group>
    <fn-group>
      <fn fn-type="financial-disclosure" id="fn7">
        <p>Fontes de financiamento: O presente estudo foi financiado por National Key Research and Develop Program of China (number 2017YFC0908802).</p>
      </fn>
    </fn-group>
  </back>
  <sub-article article-type="translation" id="TRen" xml:lang="en">
    <front-stub>
      <article-categories>
        <subj-group subj-group-type="heading">
          <subject>Original Article</subject>
        </subj-group>
      </article-categories>
      <title-group>
        <article-title>Association between Plasma Big Endothelin-1 Level and The Severity of Coronary Artery Disease in Patients with Non-ST Segment-Elevated Myocardial Infarction</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <name>
            <surname>Lyu</surname>
            <given-names>Si-qi</given-names>
          </name>
          <xref ref-type="aff" rid="aff1001">
            <sup>1</sup>
          </xref>
          <xref ref-type="aff" rid="aff2001">
            <sup>2</sup>
          </xref>
          <role>Conception and design of the research</role>
          <role>Acquisition of data</role>
          <role>Analysis and interpretation of the data</role>
          <role>Statistical analysis and Writing of the manuscript</role>
          <role>Critical revision of the manuscript for important intellectual content</role>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Zhu</surname>
            <given-names>Jun</given-names>
          </name>
          <xref ref-type="aff" rid="aff1001">
            <sup>1</sup>
          </xref>
          <xref ref-type="aff" rid="aff2001">
            <sup>2</sup>
          </xref>
          <role>Conception and design of the research</role>
          <role>Obtaining financing</role>
          <role>Critical revision of the manuscript for important intellectual content</role>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Wang</surname>
            <given-names>Juan</given-names>
          </name>
          <xref ref-type="aff" rid="aff1001">
            <sup>1</sup>
          </xref>
          <xref ref-type="aff" rid="aff2001">
            <sup>2</sup>
          </xref>
          <role>Acquisition of data</role>
          <role>Critical revision of the manuscript for important intellectual content</role>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Wu</surname>
            <given-names>Shuang</given-names>
          </name>
          <xref ref-type="aff" rid="aff1001">
            <sup>1</sup>
          </xref>
          <xref ref-type="aff" rid="aff2001">
            <sup>2</sup>
          </xref>
          <role>Critical revision of the manuscript for important intellectual content</role>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Zhang</surname>
            <given-names>Han</given-names>
          </name>
          <xref ref-type="aff" rid="aff1001">
            <sup>1</sup>
          </xref>
          <xref ref-type="aff" rid="aff2001">
            <sup>2</sup>
          </xref>
          <role>Acquisition of data</role>
          <role>Critical revision of the manuscript for important intellectual content</role>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Shao</surname>
            <given-names>Xing-hui</given-names>
          </name>
          <xref ref-type="aff" rid="aff1001">
            <sup>1</sup>
          </xref>
          <xref ref-type="aff" rid="aff2001">
            <sup>2</sup>
          </xref>
          <role>Acquisition of data</role>
          <role>Critical revision of the manuscript for important intellectual content</role>
        </contrib>
        <contrib contrib-type="author">
          <contrib-id contrib-id-type="orcid">0000-0001-9594-8133</contrib-id>
          <name>
            <surname>Yang</surname>
            <given-names>Yan-min</given-names>
          </name>
          <xref ref-type="aff" rid="aff1001">
            <sup>1</sup>
          </xref>
          <xref ref-type="aff" rid="aff2001">
            <sup>2</sup>
          </xref>
          <role>Conception and design of the research</role>
          <role>Obtaining financing</role>
          <role>Critical revision of the manuscript for important intellectual content</role>
        </contrib>
      </contrib-group>
      <aff id="aff1001">
        <label> 1 </label>
        <country country="CN">China</country>
        <institution content-type="original"> Emergency Center, Fuwai Hospital,National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing &#8211; China </institution>
      </aff>
      <aff id="aff2001">
        <label> 2 </label>
        <country country="CN">China</country>
        <institution content-type="original"> National Clinical Research Center of Cardiovascular Diseases , Fuwai Hospital,National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing &#8211; China </institution>
      </aff>
      <author-notes>
        <corresp id="c01001">Mailing Address: Yan-min Yang &#8226; Emergency Center, Fuwai Hospital &#8211; No. 167 Beilishi Road, Xicheng District Beijing 100037 E-mail: yymfuwai@163.com</corresp>
        <fn fn-type="conflict">
          <p>Potential conflict of interest</p>
          <p>No potential conflict of interest relevant to this article was reported.</p>
        </fn>
      </author-notes>
      <abstract>
        <title>Abstract</title>
        <sec>
          <title>Background</title>
          <p>Early risk stratification with simple biomarkers is essential in patients with non-ST segment-elevation myocardial infarction (NSTEMI).</p>
        </sec>
        <sec>
          <title>Objective</title>
          <p>This study aimed to evaluate the association between plasma big endothelin-1 (ET-1) level and the SYNTAX score (SS) in patients with NSTEMI.</p>
        </sec>
        <sec>
          <title>Methods</title>
          <p>A total of 766 patients with NSTEMI undergoing coronary angiography were recruited. Patients were divided into three groups: low SS (&#8804;22), intermediate SS (23-32), and high SS (&gt;32). Spearman correlation, smooth curve fitting, logistic regression, and receiver operating characteristic (ROC) curve analysis were performed to evaluate the association between plasma big ET-1 level and the SS. A p-value &lt;0.05 was considered statistically significant.</p>
        </sec>
        <sec>
          <title>Results</title>
          <p>There was a significant correlation between the big ET-1 and the SS (r=0.378, p&lt;0.001). The smoothing curve indicated a positive correlation between the plasma big ET-1 level and the SS. The ROC curve analysis showed that the area under the curve was 0.695 (0.661-0.727) and the optimal cutoff of plasma big ET-1 level was 0.35pmol/l. Logistic regression showed that elevated big ET-1 was an independent predictor of intermediate-high SS in patients with NSTEMI, whether entered as a continuous variable [OR (95% CI): 1.110 (1.053-1.170), p&lt;0.001] or as a categorical variable [OR (95% CI): 2.962 (2.073-4.233), p&lt;0.001].</p>
        </sec>
        <sec>
          <title>Conclusion</title>
          <p>In patients with NSTEMI, the plasma big ET-1 level was significantly correlated with the SS. Elevated plasma big ET-1 level was an independent predictor for intermediate-high SS.</p>
        </sec>
      </abstract>
      <kwd-group xml:lang="en">
        <kwd>Coronary Artery Disease</kwd>
        <kwd>Non S-T Elevated Myocardial Infarction</kwd>
        <kwd>Endotelin-1</kwd>
      </kwd-group>
    </front-stub>
    <body>
      <sec sec-type="intro">
        <title>Introduction</title>
        <p>As one of the leading causes of death worldwide, myocardial infarction is associated with severe public health threats and major medical expenses. <sup><xref rid="B1" ref-type="bibr">1</xref> , <xref rid="B2" ref-type="bibr">2</xref> </sup> Despite remarkable development in prevention and treatment, the morbidity and mortality of non-ST segment-elevation myocardial infarction (NSTEMI) in developing countries. <sup><xref rid="B1" ref-type="bibr">1</xref> , <xref rid="B2" ref-type="bibr">2</xref> </sup> For early risk stratification is essential and guiding management. <sup><xref rid="B1" ref-type="bibr">1</xref> , <xref rid="B2" ref-type="bibr">2</xref> </sup> Coronary angiography provides important information about the morphology, severity, and burden of atherosclerosis, which have proven to be associated with the short-term and long-term prognosis of patients with NSTEMI. <sup><xref rid="B3" ref-type="bibr">3</xref></sup> The SYNTAX (SYNergy between PCI with TAXUS&#8482; and Cardiac Surgery) score (SS), a detailed angiographic scoring scheme based on coronary anatomy and lesion characteristics, is recommended for quantifying the severity of coronary artery disease and determining proper reperfusion therapy for patients with NSTEMI. <sup><xref rid="B3" ref-type="bibr">3</xref> - <xref rid="B6" ref-type="bibr">6</xref> </sup> Identifying patients at high risk of heavy atherosclerotic burden and adverse prognosis with simple and convenient tests is crucial in implementing timely intensive care and adopting optimal management strategy, which has been indicated to reduce morbidity and mortality of NSTEMI. <sup><xref rid="B1" ref-type="bibr">1</xref> , <xref rid="B2" ref-type="bibr">2</xref> </sup> </p>
        <p>Endothelin-1 (ET-1), a peptide derived from endothelial cells, has proven to be associated with endothelial dysfunction, inflammation, and myocardial remodeling, which participate in the aggravation of atherosclerosis. <sup><xref rid="B7" ref-type="bibr">7</xref> - <xref rid="B9" ref-type="bibr">9</xref> </sup> ET-1 has been detected to be elevated in the course of acute myocardial infarction (AMI). <sup><xref rid="B8" ref-type="bibr">8</xref></sup> But due to high biologic activity and short half-life, ET-1 is rapidly cleared in the pulmonary vasculature, and its level in peripheral circulation is generally underestimated. <sup><xref rid="B7" ref-type="bibr">7</xref> , <xref rid="B8" ref-type="bibr">8</xref> </sup> Big ET-1 is the precursor of ET-1 with no biological function but a longer half-life in the peripheral circulation. In clinical settings, big ET-1 is more easily measured and widely used to evaluate the activity of the endothelial system. <sup><xref rid="B7" ref-type="bibr">7</xref> , <xref rid="B8" ref-type="bibr">8</xref> </sup> Several studies have demonstrated that elevated big ET-1 level is a risk factor for adverse prognosis in patients with heart failure, <sup><xref rid="B10" ref-type="bibr">10</xref></sup> coronary artery disease (CAD), <sup><xref rid="B11" ref-type="bibr">11</xref> - <xref rid="B15" ref-type="bibr">15</xref> </sup> and hypertrophic cardiomyopathy. <sup><xref rid="B16" ref-type="bibr">16</xref></sup> However, the association between the plasma big ET-1 level and the severity of CAD in patients with NSTEMI has not been assessed before. Therefore, we conducted a cross-sectional study to evaluate the relation of the plasma big ET-1 level with the SYNTAX score in Chinese patients with NSTEMI.</p>
      </sec>
      <sec sec-type="methods">
        <title>Methods</title>
        <sec>
          <title>Study population</title>
          <p>This study consecutively recruited patients with NSTEMI undergoing coronary angiography in the emergency department of Fuwai Hospital from July 2017 to June 2018. NSTEMI was defined as AMI without persistent ST-segment elevation. <sup><xref rid="B1" ref-type="bibr">1</xref> , <xref rid="B2" ref-type="bibr">2</xref> </sup> The diagnosis of AMI was verified according to the Universal Definition of Myocardial Infarction. <sup><xref rid="B17" ref-type="bibr">17</xref></sup> Exclusion criteria included: history of percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG), severe hepatic and renal insufficiency, active infection, systemic inflammatory diseases, and malignancy. The study was approved by the ethics committee of Fuwai Hospital and conformed to the Declaration of Helsinki. All patients have signed the informed consent for participation.</p>
        </sec>
        <sec>
          <title>Baseline</title>
          <p>Clinical data of demographics, medical histories, physical examinations, laboratory tests, imaging examinations, and therapeutic regimens was obtained by interviewing the patients, consulting their physicians, and reviewing medical records. Venous blood samples were collected from all patients on admission before coronary angiography. The plasma big ET -1 level was measured using a highly sensitive and specific commercial sandwich enzyme immunoassay (BI-20082H, Biomedica, Wien, Austria). Creatinine clearance was calculated using the Cockcroft-Gault formula. Quantitative coronary angiography was performed in multiple orthogonal views using standard techniques. The SYNTAX score was calculated using a dedicated online calculator (http://syntaxscore.org/calculator/start.htm) based on the previously reported scoring criteria. <sup><xref rid="B4" ref-type="bibr">4</xref></sup> All coronary angiograms were adjudicated independently by two experienced cardiologists blinded to the clinical data, while any disagreement would be resolved by consensus. According to the SYNTAX trial results, the study population was divided into three groups: low SS (SS&#8804;22), intermediate SS (23-32), and high SS (SS&gt;32). <sup><xref rid="B6" ref-type="bibr">6</xref></sup> </p>
        </sec>
        <sec>
          <title>Statistical analysis</title>
          <p>Continuous variables are presented as medians (interquartile ranges) and compared by Kruskal-Wallis tests, as the data are not normally distributed according to Kolmogorov&#8211;Smirnov tests. Categorical variables are presented as percentages and compared by Pearson&#8217;s &#967;2 test or Fisher&#8217;s exact test. For multiple comparisons, the Bonferroni correction was used to adjust the significance level. The relationship between the plasma big ET-1 level and SS was evaluated using the Spearman correlation analysis. Smooth curve fitting adjusted for potential confounders was conducted to analyze the relationship between the plasma big ET-1 level and the SS. The receiver operating characteristic (ROC) curve was constructed to assess the predictive ability of the plasma big ET-1 level to identify intermediate-high SS. The optimal cut-off value of the plasma big ET-1 level for predicting intermediate-high SS was identified as the point with the highest Youden index (Sensitivity+Specificity-1) in the ROC curve. Univariable and multivariable logistic regressions were performed to identify independent predictors for intermediate-high SS, while odds ratio (OR) and 95% confidence interval (CI) were calculated. Three multivariable models consisting of different covariables were constructed to evaluate the consistency of the association between the plasma big ET-1 level and intermediate-high SS. Model 1 was adjusted for age and gender. In Model 2, variables with a p-value &lt;0.10 in the univariable models or clinically relevant with the CAD severity were included. In Model 3, the aforementioned variables were entered into the multivariable analysis with the backward LR (likelihood ratio) method. Subgroup analyses were performed to assess the homogeneity of the association between high big ET-1 and intermediate-high SS. A two-tailed p-value &lt;0.05 was defined as statistically significant. All statistical analyses were performed using SPSS, version 25.0 (IBM Corporation, New York, USA).</p>
        </sec>
      </sec>
      <sec sec-type="results">
        <title>Results</title>
        <p>From July 2017 to June 2018, a total of 766 patients who were admitted to the emergency department with documented NSTEMI were recruited in this study (Supplementary <xref rid="f02001" ref-type="fig">Figure 1</xref> ). Their baseline characteristics are summarized in <xref rid="t1001" ref-type="table">Table 1</xref> . Among the 545 male and 221 female patients with a median age of 64 years, the median SS was 15 (interquartile range: 8-24.5). According to the SS, patients were divided into three groups: low SS (&#8804;22, n=531), intermediate SS (23-32, n=132), and high SS (&gt;32, n=103). Compared to patients with low SS, NSTEMI patients with intermediate SS and high SS were older, and had a worse Killip class, a lower left ventricular ejection fraction (LVEF), and a higher GRACE score (all p&lt;0.05). Patients with intermediate SS and high SS were more likely to have hypertension, diabetes mellitus, stroke/transient ischemic attack (TIA), peripheral arterial disease, and renal insufficiency (all p&lt;0.05). In addition, they tended to have increased hemoglobin A1c, free fatty acid, N-terminal pro-B type natriuretic peptide (NT-proBNP), high sensitivity C reactive protein (hs-CRP), and big ET-1, but they presented decreased hemoglobin and creatinine clearance (all p&lt;0.05). As for treatments, patients with intermediate SS and high SS presented a lower rate of receiving angiotensin-converting enzyme inhibitors (ACEI)/angiotensin receptor blockers (ARB) but a higher rate of spironolactone and diuretics use (all p&lt;0.001).</p>
        <p>
          <fig id="f02001">
            <label>Figure 1</label>
            <caption>
              <title>&#8211; Receiver operating characteristic (ROC) curve of the plasma big endothelin-1 level to detect intermediate-high SYNTAX score</title>
            </caption>
            <graphic xlink:href="1678-4170-abc-120-02-e20220294-20294-gf01-en.tif"/></fig>
        </p>
        <p>
          <table-wrap id="t1001">
            <label>Table 1</label>
            <caption>
              <title>&#8211; Clinical characteristics of NSTEMI patients stratified by the SYNTAX score</title>
            </caption>
            <table frame="hsides" rules="groups">
              <colgroup width="17%">
                <col/>
                <col/>
                <col/>
                <col/>
                <col/>
                <col/>
              </colgroup>
              <thead>
                <tr>
                  <th align="left">Variables</th>
                  <th>Overall (n=766)</th>
                  <th>Low SYNTAX score (&#8804;22, n=531)</th>
                  <th>Intermediate SYNTAX score (23-32, n=132)</th>
                  <th>High SYNTAX score (&gt;32, n=103)</th>
                  <th>p-value</th>
                </tr>
              </thead>
              <tbody>
                <tr>
                  <td colspan="6">
                    <bold>Demographics</bold>
                  </td>
                </tr>
                <tr>
                  <td> Age(years)</td>
                  <td align="center">64 (56. 71)</td>
                  <td align="center">63 (55. 70) <sup>bc</sup> </td>
                  <td align="center">66 (60. 73) <sup>a</sup> </td>
                  <td align="center">68 (61. 77) <sup>a</sup> </td>
                  <td align="center">&lt;0.001</td>
                </tr>
                <tr>
                  <td> Female gender, n (%)</td>
                  <td align="center">221 (28.9)</td>
                  <td align="center">149 (28.1)</td>
                  <td align="center">35 (26.5)</td>
                  <td align="center">37 (35.9)</td>
                  <td align="center">0.221</td>
                </tr>
                <tr>
                  <td> Body mass index (kg/m2)</td>
                  <td align="center">25.7 (23.7. 27.7)</td>
                  <td align="center">25.8 (23.8. 27.8)</td>
                  <td align="center">25.8 (24.2. 28.0)</td>
                  <td align="center">24.6 (23.2. 26.9)</td>
                  <td align="center">0.057</td>
                </tr>
                <tr>
                  <td> Heart rate (bpm)</td>
                  <td align="center">72 (64. 82)</td>
                  <td align="center">71 (64. 81)</td>
                  <td align="center">74 (66. 82)</td>
                  <td align="center">75 (64. 85)</td>
                  <td align="center">0.086</td>
                </tr>
                <tr>
                  <td> Systolic blood pressure (mmHg)</td>
                  <td align="center">140 (124. 153)</td>
                  <td align="center">140 (123. 154)</td>
                  <td align="center">138 (125. 153)</td>
                  <td align="center">139 (123. 152)</td>
                  <td align="center">0.966</td>
                </tr>
                <tr>
                  <td> Diastolic blood pressure (mmHg)</td>
                  <td align="center">79 (69. 90)</td>
                  <td align="center">80 (69. 90)</td>
                  <td align="center">80 (70. 90)</td>
                  <td align="center">77.0 (68. 88)</td>
                  <td align="center">0.443</td>
                </tr>
                <tr>
                  <td>
                    <bold>Killip class, n (%)</bold>
                  </td>
                  <td> </td>
                  <td> </td>
                  <td> </td>
                  <td> </td>
                  <td align="center">0.011</td>
                </tr>
                <tr>
                  <td> I</td>
                  <td align="center">679 (88.6)</td>
                  <td align="center">485 (91.3) <sup>b</sup> </td>
                  <td align="center">106 (80.3) <sup>a</sup> </td>
                  <td align="center">88 (85.4)</td>
                  <td> </td>
                </tr>
                <tr>
                  <td> II</td>
                  <td align="center">60 (7.8)</td>
                  <td align="center">31 (5.8)</td>
                  <td align="center">19 (14.4)</td>
                  <td align="center">10 (9.7)</td>
                  <td> </td>
                </tr>
                <tr>
                  <td> III</td>
                  <td align="center">19 (2.5)</td>
                  <td align="center">10 (1.9)</td>
                  <td align="center">5 (3.8)</td>
                  <td align="center">4 (3.9)</td>
                  <td> </td>
                </tr>
                <tr>
                  <td> IV</td>
                  <td align="center">8 (1.0)</td>
                  <td align="center">5 (0.9)</td>
                  <td align="center">2 (1.5)</td>
                  <td align="center">1 (1.0)</td>
                  <td> </td>
                </tr>
                <tr>
                  <td> LVEF(%)</td>
                  <td align="center">60 (55. 62)</td>
                  <td align="center">60 (57. 63) <sup>bc</sup> </td>
                  <td align="center">58 (48. 60) <sup>a</sup> </td>
                  <td align="center">58 (49. 60) <sup>a</sup> </td>
                  <td align="center">&lt;0.001</td>
                </tr>
                <tr>
                  <td> The GRACE score</td>
                  <td align="center">113 (98. 133)</td>
                  <td align="center">111 (95. 129) <sup>bc</sup> </td>
                  <td align="center">122 (104. 144) <sup>a</sup> </td>
                  <td align="center">124 (106. 145) <sup>a</sup> </td>
                  <td align="center">&lt;0.001</td>
                </tr>
                <tr>
                  <td>
                    <bold>Medical histories, n (%)</bold>
                  </td>
                  <td> </td>
                  <td> </td>
                  <td> </td>
                  <td> </td>
                  <td> </td>
                </tr>
                <tr>
                  <td> Hypertension</td>
                  <td align="center">565 (73.8)</td>
                  <td align="center">373 (70.2) <sup>b</sup> </td>
                  <td align="center">108 (81.8) <sup>a</sup> </td>
                  <td align="center">84 (81.6)</td>
                  <td align="center">0.004</td>
                </tr>
                <tr>
                  <td> Hyperlipidemia</td>
                  <td align="center">481 (62.8)</td>
                  <td align="center">325 (61.2)</td>
                  <td align="center">86 (65.2)</td>
                  <td align="center">70 (68.0)</td>
                  <td align="center">0.356</td>
                </tr>
                <tr>
                  <td> Diabetes mellitus</td>
                  <td align="center">330 (43.1)</td>
                  <td align="center">200 (37.7) <sup>c</sup> </td>
                  <td align="center">65 (49.2)</td>
                  <td align="center">65 (63.1) <sup>a</sup> </td>
                  <td align="center">&lt;0.001</td>
                </tr>
                <tr>
                  <td> Heart failure</td>
                  <td align="center">88 (11.5)</td>
                  <td align="center">35 (6.6) <sup>bc</sup> </td>
                  <td align="center">31 (23.5) <sup>a</sup> </td>
                  <td align="center">22 (21.4) <sup>a</sup> </td>
                  <td align="center">&lt;0.001</td>
                </tr>
                <tr>
                  <td> Stroke/TIA</td>
                  <td align="center">129 (16.8)</td>
                  <td align="center">78 (14.7)</td>
                  <td align="center">26 (19.7)</td>
                  <td align="center">25 (24.3)</td>
                  <td align="center">0.037</td>
                </tr>
                <tr>
                  <td> Peripheral arterial disease</td>
                  <td align="center">78 (10.2)</td>
                  <td align="center">40 (7.5) <sup>bc</sup> </td>
                  <td align="center">22 (16.7) <sup>a</sup> </td>
                  <td align="center">16 (15.5) <sup>a</sup> </td>
                  <td align="center">0.001</td>
                </tr>
                <tr>
                  <td> Creatinine clearance &lt;60ml/min</td>
                  <td align="center">140 (18.3)</td>
                  <td align="center">76 (14.3) <sup>bc</sup> </td>
                  <td align="center">31 (23.5) <sup>a</sup> </td>
                  <td align="center">33 (32.0) <sup>a</sup> </td>
                  <td align="center">&lt;0.001</td>
                </tr>
                <tr>
                  <td> Tobacco use</td>
                  <td align="center">436 (56.9)</td>
                  <td align="center">310 (58.4)</td>
                  <td align="center">72 (54.5)</td>
                  <td align="center">54 (52.4)</td>
                  <td align="center">0.446</td>
                </tr>
                <tr>
                  <td colspan="6">
                    <bold>Laboratory tests, median (IQR)</bold>
                  </td>
                </tr>
                <tr>
                  <td> White blood cell count (*109/l)</td>
                  <td align="center">7.7 (6.4. 9.4)</td>
                  <td align="center">7.6 (6.4. 9.4)</td>
                  <td align="center">7.9 (6.4. 9.4)</td>
                  <td align="center">7.7 (6.3. 9.5)</td>
                  <td align="center">0.732</td>
                </tr>
                <tr>
                  <td> Hemoglobin (g/l)</td>
                  <td align="center">141 (128. 151)</td>
                  <td align="center">143 (131. 153) <sup>bc</sup> </td>
                  <td align="center">138 (128. 150) <sup>a</sup> </td>
                  <td align="center">131 (122. 143) <sup>a</sup> </td>
                  <td align="center">&lt;0.001</td>
                </tr>
                <tr>
                  <td> RDW (%)</td>
                  <td align="center">12.6 (12.1. 13.1)</td>
                  <td align="center">12.6 (12.1. 13.0)</td>
                  <td align="center">12.6 (12.2. 13.1)</td>
                  <td align="center">12.7 (12.3. 13.2)</td>
                  <td align="center">0.123</td>
                </tr>
                <tr>
                  <td> Platelet coun t(*109/l)</td>
                  <td align="center">222 (184. 264)</td>
                  <td align="center">223 (186. 262)</td>
                  <td align="center">226 (184. 272)</td>
                  <td align="center">210 (178. 257)</td>
                  <td align="center">0.232</td>
                </tr>
                <tr>
                  <td> Creatinine clearance (ml/min)</td>
                  <td align="center">84.2 (65.8. 105.8)</td>
                  <td align="center">87.5 (69.2. 109.9) <sup>bc</sup> </td>
                  <td align="center">78.8 (62.8. 99.4) <sup>ac</sup> </td>
                  <td align="center">73.7 (55.8. 88.7) <sup>ab</sup> </td>
                  <td align="center">&lt;0.001</td>
                </tr>
                <tr>
                  <td> Hemoglobin A1c (%)</td>
                  <td align="center">6.2 (5.7. 7.2)</td>
                  <td align="center">6.1 (5.7. 6.8) <sup>c</sup> </td>
                  <td align="center">6.3 (5.7. 7.4) <sup>c</sup> </td>
                  <td align="center">6.8 (6.0. 8.1) <sup>ab</sup> </td>
                  <td align="center">&lt;0.001</td>
                </tr>
                <tr>
                  <td> LDL-C (mmol/l)</td>
                  <td align="center">2.3 (1.8. 2.9)</td>
                  <td align="center">2.3 (1.8. 2.8)</td>
                  <td align="center">2.4 (1.8. 3.1)</td>
                  <td align="center">2.5 (1.9. 3.2)</td>
                  <td align="center">0.134</td>
                </tr>
                <tr>
                  <td> Lipoprotein(a) (mg/l)</td>
                  <td align="center">204.5 (89.1. 419.2)</td>
                  <td align="center">195.1 (86.9. 385.8)</td>
                  <td align="center">220.6 (90.7. 450.8)</td>
                  <td align="center">221.4 (89.9. 600.1)</td>
                  <td align="center">0.150</td>
                </tr>
                <tr>
                  <td> Free fatty acid (mmol/l)</td>
                  <td align="center">0.6 (0.4. 0.8)</td>
                  <td align="center">0.5 (0.4. 0.7) <sup>b</sup> </td>
                  <td align="center">0.6 (0.4. 0.9) <sup>a</sup> </td>
                  <td align="center">0.6 (0.4. 0.8)</td>
                  <td align="center">0.014</td>
                </tr>
                <tr>
                  <td> Troponin I (ng/ml)</td>
                  <td align="center">0.3 (0.1. 1.2)</td>
                  <td align="center">0.3 (0.1. 1.0) <sup>b</sup> </td>
                  <td align="center">0.5 (0.1. 2.1) <sup>a</sup> </td>
                  <td align="center">0.3 (0.1. 1.1)</td>
                  <td align="center">0.010</td>
                </tr>
                <tr>
                  <td> NT-proBNP (pg/ml)</td>
                  <td align="center">241.0 (78.1. 1117.0)</td>
                  <td align="center">172.5 (57.6. 658.6) <sup>bc</sup> </td>
                  <td align="center">679.8 (150.0. 1939.0) <sup>a</sup> </td>
                  <td align="center">1106.0 (225.6. 4091.0) <sup>a</sup> </td>
                  <td align="center">&lt;0.001</td>
                </tr>
                <tr>
                  <td> D-dimer (ug/ml)</td>
                  <td align="center">0.3 (0.2. 0.5)</td>
                  <td align="center">0.3 (0.2. 0.4) <sup>bc</sup> </td>
                  <td align="center">0.3 (0.2. 0.6) <sup>a</sup> </td>
                  <td align="center">0.4 (0.3. 0.8) <sup>a</sup> </td>
                  <td align="center">&lt;0.001</td>
                </tr>
                <tr>
                  <td> Hs-CRP (mg/l)</td>
                  <td align="center">3.9 (1.5. 9.6)</td>
                  <td align="center">3.3 (1.4. 8.9) <sup>b</sup> </td>
                  <td align="center">6.3 (2.0. 10.1) <sup>a</sup> </td>
                  <td align="center">4.4 (1.5. 11.2)</td>
                  <td align="center">0.011</td>
                </tr>
                <tr>
                  <td> Big endothelin-1 (pmol/l)</td>
                  <td align="center">0.34 (0.23. 0.53)</td>
                  <td align="center">0.30 (0.21. 0.45) <sup>bc</sup> </td>
                  <td align="center">0.41 (0.28. 0.58) <sup>ac</sup> </td>
                  <td align="center">0.58 (0.36. 0.92) <sup>ab</sup> </td>
                  <td align="center">&lt;0.001</td>
                </tr>
                <tr>
                  <td colspan="6">
                    <bold>Medications, n (%)</bold>
                  </td>
                </tr>
                <tr>
                  <td> Aspirin</td>
                  <td align="center">757 (98.8)</td>
                  <td align="center">527 (99.2)</td>
                  <td align="center">129 (97.7)</td>
                  <td align="center">101 (98.1)</td>
                  <td align="center">0.148</td>
                </tr>
                <tr>
                  <td> Clopidogrel</td>
                  <td align="center">519 (67.8)</td>
                  <td align="center">350 (65.9)</td>
                  <td align="center">99 (75.0)</td>
                  <td align="center">70 (68.0)</td>
                  <td align="center">0.135</td>
                </tr>
                <tr>
                  <td> Ticagrelor</td>
                  <td align="center">220 (28.7)</td>
                  <td align="center">168 (31.6)</td>
                  <td align="center">29 (22.0)</td>
                  <td align="center">23 (22.3)</td>
                  <td align="center">0.027</td>
                </tr>
                <tr>
                  <td> Oral anticoagulants</td>
                  <td align="center">22 (2.9)</td>
                  <td align="center">11 (2.1)</td>
                  <td align="center">7 (5.3)</td>
                  <td align="center">4 (3.9)</td>
                  <td align="center">0.086</td>
                </tr>
                <tr>
                  <td> Statins</td>
                  <td align="center">748 (97.7)</td>
                  <td align="center">518 (97.6)</td>
                  <td align="center">129 (97.7)</td>
                  <td align="center">101 (98.1)</td>
                  <td align="center">1.000</td>
                </tr>
                <tr>
                  <td> &#946; blockers</td>
                  <td align="center">669 (87.3)</td>
                  <td align="center">456 (85.9)</td>
                  <td align="center">118 (89.4)</td>
                  <td align="center">95 (92.2)</td>
                  <td align="center">0.152</td>
                </tr>
                <tr>
                  <td> ACEI/ARB</td>
                  <td align="center">487 (63.6)</td>
                  <td align="center">364 (68.5) <sup>bc</sup> </td>
                  <td align="center">75 (56.8) <sup>a</sup> </td>
                  <td align="center">48 (46.6) <sup>a</sup> </td>
                  <td align="center">&lt;0.001</td>
                </tr>
                <tr>
                  <td> Spironolactone</td>
                  <td align="center">84 (11.0)</td>
                  <td align="center">38 (7.2) <sup>bc</sup> </td>
                  <td align="center">22 (16.7) <sup>a</sup> </td>
                  <td align="center">24 (23.3) <sup>a</sup> </td>
                  <td align="center">&lt;0.001</td>
                </tr>
                <tr>
                  <td> Diuretics</td>
                  <td align="center">154 (20.1)</td>
                  <td align="center">70 (13.2) <sup>bc</sup> </td>
                  <td align="center">40 (30.3) <sup>a</sup> </td>
                  <td align="center">44 (42.7) <sup>a</sup> </td>
                  <td align="center">&lt;0.001</td>
                </tr>
                <tr>
                  <td> Proton pump inhibitors</td>
                  <td align="center">413 (53.9)</td>
                  <td align="center">291 (54.8)</td>
                  <td align="center">67 (50.8)</td>
                  <td align="center">55 (53.4)</td>
                  <td align="center">0.702</td>
                </tr>
              </tbody>
            </table>
            <table-wrap-foot>
              <fn id="TFN1001">
                <p>
                  <italic>NSTEMI: non-ST segment elevated myocardial infarction; LVEF: left ventricular ejection fraction; TIA: transient ischemic attack; CAD: coronary artery disease; RDW: red blood cell distribution width; LDL-C: low-density lipoprotein cholesterol; NT-proBNP: N-terminal pro-B type natriuretic peptide; HsCRP: high sensitivity C reactive protein; ACEI: angiotensin-converting enzyme inhibitors; ARB: angiotensin receptor blockers. <sup><italic>a</italic></sup> p&lt;0.0167 versus the low SYNTAX score group. <sup><italic>b</italic></sup> p&lt;0.0167 versus the intermediate SYNTAX score group. <sup><italic>c</italic></sup> p&lt;0.0167 versus the high SYNTAX score group.</italic>
                </p>
              </fn>
            </table-wrap-foot>
          </table-wrap>
        </p>
        <p>According to the Spearman correlation analysis, there was a significant correlation between the big ET-1 and the SS (r=0.378, p&lt;0.001). The smoothing curve indicated a positive correlation between the plasma big ET-1 level and the SS, after adjustment for potential confounders (<xref rid="f01001" ref-type="fig">Central Figure</xref>). The ROC curve of the plasma big ET-1 level for predicting intermediate-high SS is displayed in <xref rid="f02001" ref-type="fig">Figure 1</xref> . The area under the curve (AUC) was 0.695 (95% CI: 0.661-0.727, p&lt;0.001) and the optimal cutoff of the plasma big ET-1 level was 0.35pmol/l, with a sensitivity of 68.9% and a specificity of 62.9%. Based on this cutoff, patients were categorized into two groups: big ET-1 &#8804;0.35pmol/l and big ET-1 &gt;0.35pmol/l. Regardless of entering into the univariable logistic regression models as a continuous variable or as a categorical variable, the plasma big ET-1 level was significantly associated with intermediate-high SS. To evaluate the association between the plasma big ET-1 level and the SS, three models with different covariables were constructed and indicated consistent results ( <xref rid="t2001" ref-type="table">Table 2</xref> ). After adjusting for age, female gender, body mass index, Killip class, LVEF, heart failure, hypertension, diabetes mellitus, stroke/TIA, peripheral arterial disease, tobacco use, hemoglobin, red blood cell distribution width, creatinine clearance, hemoglobin A1c, low-density lipoprotein cholesterol, lipoprotein(a), free fatty acid, d-dimer, troponin I, NT-proBNP, and hs-CRP in the multivariable logistic regression analysis with backward LR method, elevated big ET-1 was still an independent predictor of intermediate-high SS in patients with NSTEMI [OR (95% CI): 1.110 (1.053-1.170), p&lt;0.001]. Patients with a plasma big ET level &gt;0.35pmol/l were remarkably more likely to have an intermediate-high SS than were those with a plasma big ET level &#8804;0.35pmol/l [OR (95% CI): 2.962 (2.073-4.233), p&lt;0.001] ( <xref rid="t2001" ref-type="table">Table 2</xref> ). Subgroup analysis demonstrated that the association between big ET-1 and intermediate-high SS was constant across subgroups of age, gender, heart failure, hypertension, diabetes mellitus, peripheral arterial disease, renal insufficiency, and tobacco use (all p&gt;0.05 for interaction) ( <xref rid="f03001" ref-type="fig">Figure 2</xref> ).</p>
        <p>
          <fig id="f01001">
            <label>Central Illustration</label>
            <caption>
              <title>: Association between Plasma Big Endothelin-1 Level and The Severity of Coronary Artery Disease in Patients with Non-ST Segment-Elevated Myocardial Infarction</title>
            </caption>
            <attrib>
              <italic>The relationship between the plasma big endothelin-1 level and the SYNTAX score by smooth curve fitting.</italic>
            </attrib>
            <attrib>
              <italic>* Adjusted for female gender, heart failure, hypertension, diabetes mellitus, peripheral arterial disease, hemoglobin, red blood cell distribution width, lipoprotein(a), free fatty acid, and NT-pro BNP. The histogram indicated the distribution of plasma big ET-1 levels.</italic>
            </attrib>
            <graphic xlink:href="1678-4170-abc-120-02-e20220294-20294-gf02-en.tif"/></fig>
        </p>
        <p>
          <table-wrap id="t2001">
            <label>Table 2</label>
            <caption>
              <title>&#8211; Association between the plasma big ET-1 level and intermediate-high SYNTAX score according to logistic regression</title>
            </caption>
            <table frame="hsides" rules="groups">
              <colgroup width="11%">
                <col/>
                <col/>
                <col/>
                <col/>
                <col/>
                <col/>
                <col/>
                <col/>
                <col/>
                <col/>
              </colgroup>
              <thead>
                <tr>
                  <th align="left" rowspan="3">Variables</th>
                  <th colspan="2" rowspan="2">Univariable logistic regression</th>
                  <th colspan="6">Multivariable logistic regression</th>
                </tr>
                <tr>
                  <th colspan="2">Model 1 <sup><bold>a</bold></sup> </th>
                  <th colspan="2">Model 2 <sup><bold>b</bold></sup> </th>
                  <th colspan="2">Model 3 <sup><bold>c</bold></sup> </th>
                </tr>
                <tr>
                  <th>OR (95% CI)</th>
                  <th>p-value</th>
                  <th>OR (95% CI)</th>
                  <th>p-value</th>
                  <th>OR (95% CI)</th>
                  <th>p-value</th>
                  <th>OR (95% CI)</th>
                  <th>p-value</th>
                </tr>
              </thead>
              <tbody>
                <tr>
                  <td colspan="3">
                    <bold>Plasma big ET-1 level as a continuous variable</bold>
                  </td>
                  <td> </td>
                  <td> </td>
                  <td> </td>
                  <td> </td>
                  <td> </td>
                  <td> </td>
                </tr>
                <tr>
                  <td> Big ET-1, per 0.1pmol/l</td>
                  <td align="center">1.171 (1.115-1.230)</td>
                  <td align="center">&lt;0.001</td>
                  <td align="center">1.156 (1.101-1.215)</td>
                  <td align="center">&lt;0.001</td>
                  <td align="center">1.111 (1.051-1.175)</td>
                  <td align="center">&lt;0.001</td>
                  <td align="center">1.110 (1.053-1.170)</td>
                  <td align="center">&lt;0.001</td>
                </tr>
                <tr>
                  <td colspan="3">
                    <bold>Plasma big ET-1 level as a categorical variable</bold>
                  </td>
                  <td> </td>
                  <td> </td>
                  <td> </td>
                  <td> </td>
                  <td> </td>
                  <td> </td>
                </tr>
                <tr>
                  <td> Big ET-1 &#8804;0.35pmol/l</td>
                  <td align="center" colspan="2">1 (reference)</td>
                  <td align="center" colspan="2">1 (reference)</td>
                  <td align="center" colspan="2">1 (refer&#234;ncia)</td>
                  <td align="center" colspan="2">1 (reference)</td>
                </tr>
                <tr>
                  <td> Big ET-1 &gt;0,35 pmol/l</td>
                  <td align="center">3.762 (2.711-5.221)</td>
                  <td align="center">&lt;0.001</td>
                  <td align="center">3.450 (2.474-4.809)</td>
                  <td align="center">&lt;0.001</td>
                  <td align="center">2.796 (1.937-4.036)</td>
                  <td align="center">&lt;0.001</td>
                  <td align="center">2.962 (2.073-4.233)</td>
                  <td align="center">&lt;0.001</td>
                </tr>
              </tbody>
            </table>
            <table-wrap-foot>
              <fn id="TFN2001">
                <p>
                  <italic>OR: odd ratio; CI: confidence interval; ET-1: endothelin-1. a) Model 1 included age, gender, and plasma big ET-1 level. b) Model 2 included age, gender, BMI, Killip class, LVEF, heart failure, hypertension, diabetes mellitus, stroke/TIA, peripheral arterial disease, tobacco use, hemoglobin, red blood cell distribution width, creatinine clearance, hemoglobin A1c, LDL-C, lipoprotein(a), free fatty acid, d-dimer, troponin I, NT-proBNP, hs-CRP, and plasma big ET-1 level. c) Model 3 included age, gender, BMI, Killip class, LVEF, heart failure, hypertension, diabetes mellitus, stroke/TIA, peripheral arterial disease, tobacco use, hemoglobin, red blood cell distribution width, creatinine clearance, hemoglobin A1c, LDL-C, lipoprotein(a), free fatty acid, d-dimer, troponin I, NT-proBNP, hs-CRP, and plasma big ET-1 level with backward LR method.</italic>
                </p>
              </fn>
            </table-wrap-foot>
          </table-wrap>
        </p>
        <p>
          <fig id="f03001">
            <label>Figure 2</label>
            <caption>
              <title>&#8211; Subgroup analysis for associations between plasma big endothelin-1 level and intermediate-high SYNTAX score in patients with NSTEMI. NSTEMI: non-ST segment elevated myocardial infarction; ET-1: endothelin-1; CI: confidence interval.</title>
            </caption>
            <attrib>* Adjusted for female gender, heart failure, hypertension, diabetes mellitus, peripheral arterial disease, hemoglobin, red blood cell distribution width, lipoprotein(a), free fatty acid, and NT-pro BNP.</attrib>
            <graphic xlink:href="1678-4170-abc-120-02-e20220294-20294-gf03-en.tif"/></fig>
        </p>
      </sec>
      <sec sec-type="discussion">
        <title>Discussion</title>
        <p>The present study demonstrated a significant positive correlation between big ET-1 and the SS in patients with NSTEMI. A high plasma big ET-1 level was an independent predictor for intermediate-high SS. ROC curve analysis indicated that the discriminative performance of big ET-1 is moderate, and the optimal cutoff value of the plasma big ET-1 level for intermediate-high SS was 0.35pmol/L. Results of subgroup analyses were consistent with those for overall patients.</p>
        <p>With the development of intensive care and invasive procedures, the prognosis of NSTEMI has improved significantly in recent decades. <sup><xref rid="B1" ref-type="bibr">1</xref> , <xref rid="B2" ref-type="bibr">2</xref> </sup> According to clinical guidelines, risk stratification is recommended for patients with NSTEMI in order to determine the appropriate management strategy. <sup><xref rid="B1" ref-type="bibr">1</xref> , <xref rid="B2" ref-type="bibr">2</xref> </sup> Diverse angiographic patterns of CAD could be found in patients with NSTEMI, which have a prominent influence on treatment choices and subsequent prognosis. <sup><xref rid="B1" ref-type="bibr">1</xref> , <xref rid="B2" ref-type="bibr">2</xref> </sup> The SYNTAX score is a classical anatomic scoring system recommended for quantifying the complexity of CAD and has been confirmed to be an independent predictor of adverse outcomes in patients with NSTEMI. <sup><xref rid="B3" ref-type="bibr">3</xref> - <xref rid="B5" ref-type="bibr">5</xref> </sup> A large proportion of patients with NSTEMI tended to have multi-vessel CAD. <sup><xref rid="B1" ref-type="bibr">1</xref> , <xref rid="B2" ref-type="bibr">2</xref> </sup> Early identification of patients with different CAD severity and adoption of proper management strategies were of great importance in order to reduce adverse outcomes in patients with NSTEMI. <sup><xref rid="B1" ref-type="bibr">1</xref> , <xref rid="B2" ref-type="bibr">2</xref> , <xref rid="B6" ref-type="bibr">6</xref> </sup> </p>
        <p>Endothelin is a peptide of 21 amino acids firstly discovered in 1985. <sup><xref rid="B18" ref-type="bibr">18</xref></sup> Subsequently, three isoforms of ET: ET-1, ET-2, and ET-3, have been identified. <sup><xref rid="B7" ref-type="bibr">7</xref> - <xref rid="B9" ref-type="bibr">9</xref> </sup> ET-1, the major isoform in the human cardiovascular system, can be produced by a variety of cells, including vascular endothelial cells, smooth muscle cells, cardiomyocytes, and fibroblasts. <sup><xref rid="B8" ref-type="bibr">8</xref> , <xref rid="B9" ref-type="bibr">9</xref> </sup> ET-1 is a biologically active peptide derived from a 39-amino acid intermediate, big ET-1. Due to its rapid clearance and short half-life, the measurement of ET-1 in circulation is relatively difficult and often underestimated. Hence, big ET-1, the precursor with a longer half-life, could act as a more practical indicator for the activation of the endothelial system. <sup><xref rid="B7" ref-type="bibr">7</xref> - <xref rid="B9" ref-type="bibr">9</xref> </sup> Previous studies have revealed that ET-1 plays an important role in endothelial dysfunction, inflammation, and myocardial remodeling. <sup><xref rid="B7" ref-type="bibr">7</xref> - <xref rid="B9" ref-type="bibr">9</xref> </sup> All of these are well-established risk factors for the occurrence, progression, and deterioration of CAD.</p>
        <p>Plasma concentrations of ET-1 and big ET-1 have proven to be elevated in patients with AMI, <sup><xref rid="B8" ref-type="bibr">8</xref></sup> relatively higher in patients with STEMI than those with NSTEMI. <sup><xref rid="B19" ref-type="bibr">19</xref></sup> Tsutamoto et al. <sup><xref rid="B20" ref-type="bibr">20</xref></sup> found that ET-1 is associated with the modulation of post-infarct LV remodeling. <sup><xref rid="B20" ref-type="bibr">20</xref></sup> A prospective study of 128 STEMI patients undergoing primary PCI demonstrated that the ET-1 level upon admission was an independent predictor of no-reflow and reduced left ventricular ejection fraction. <sup><xref rid="B11" ref-type="bibr">11</xref></sup> In addition, big ET-1 has also been identified as a risk factor for stent thrombosis in patients undergoing coronary stent implantation. <sup><xref rid="B21" ref-type="bibr">21</xref></sup> All of these play important roles in the pathological process of AMI, leading to unfavorable clinical outcomes. Abundant studies have indicated that ET-1 and big ET-1 are predictors of adverse events in patients with AMI. <sup><xref rid="B11" ref-type="bibr">11</xref> - <xref rid="B15" ref-type="bibr">15</xref> </sup> </p>
        <p>Although the relation between ET-1 and prognosis has been extensively studied, the association between big ET-1 and the severity of CAD in patients with AMI has yet to be explored. Several studies have investigated the relation of ET-1 with the presence and severity of CAD in patients without index MI, but have come to controversial conclusions. <sup><xref rid="B19" ref-type="bibr">19</xref> , <xref rid="B22" ref-type="bibr">22</xref> - <xref rid="B25" ref-type="bibr">25</xref> </sup> In a cohort of patients undergoing coronary angiography without prevalent AMI, ET-1 levels were not related to the presence or severity of CAD. <sup><xref rid="B19" ref-type="bibr">19</xref></sup> On the other hand, Kanaya et al. <sup><xref rid="B22" ref-type="bibr">22</xref></sup> undertook a cross-sectional analysis of 961 patients and revealed that ET-1 was significantly related to the presence of CAD in women of all ages, but only in men &#8805;75 years old. <sup><xref rid="B22" ref-type="bibr">22</xref></sup> Another study of Chinese patients undergoing coronary computed tomography angiography scanning showed that big ET-1 was significantly associated with the presence of noncalcified plaques/mixed plaques and could act as an independent predictor for coronary artery calcification, all of which have been indicated to be related to atherosclerotic burden and adverse outcomes. <sup><xref rid="B23" ref-type="bibr">23</xref> , <xref rid="B24" ref-type="bibr">24</xref> </sup> Meanwhile, big ET-1 has proven to be independently related to the severity of stable CAD in another cohort of 963 patients. <sup><xref rid="B25" ref-type="bibr">25</xref></sup> As for patients with AMI, studies on the association between big ET-1 and the severity of CAD are still lacking. To the best of our knowledge, the present study indicated that big ET-1 is an independent marker of CAD severity assessed by the SS in patients with NSTEMI for the first time.</p>
        <p>Explanations for the association between big ET-1 and CAD severity in NSTEMI have not been fully elucidated and might be manifold. Firstly, big ET-1 is a practical marker of endothelial dysfunction characterized by vasodilatation impairment. <sup><xref rid="B26" ref-type="bibr">26</xref> , <xref rid="B27" ref-type="bibr">27</xref> </sup> It&#8217;s well-established that endothelial dysfunction participates in the development of NSTEMI. <sup><xref rid="B12" ref-type="bibr">12</xref> , <xref rid="B14" ref-type="bibr">14</xref> , <xref rid="B28" ref-type="bibr">28</xref> , <xref rid="B29" ref-type="bibr">29</xref> </sup> In addition, ET-1 is a potent vasoconstrictor that is essential in the pathophysiologic mechanism of NSTEMI. <sup><xref rid="B27" ref-type="bibr">27</xref></sup> Meanwhile, elevated ET-1 could lead to decreased synthesis and increased degradation of nitric oxide. <sup><xref rid="B7" ref-type="bibr">7</xref> - <xref rid="B9" ref-type="bibr">9</xref> </sup> Accordingly, ET-1 plays a crucial role in maintaining a balance between vasoconstriction and vasodilatation of the coronary artery. <sup><xref rid="B27" ref-type="bibr">27</xref></sup> Decreased blood flow due to artery stenosis is one of the most important stimuli modulating ET-1 production and release, which might act as a link between ET-1 and the SS. <sup><xref rid="B29" ref-type="bibr">29</xref></sup> Secondly, ET-1 is closely related to the activation of inflammation. <sup><xref rid="B7" ref-type="bibr">7</xref> - <xref rid="B9" ref-type="bibr">9</xref> </sup> It&#8217;s well-established that inflammation is an initial factor in the complicated mechanism of CAD. <sup><xref rid="B30" ref-type="bibr">30</xref></sup> Besides endothelial cells, a variety of inflammatory cells, such as macrophages and polymorphonuclear leukocytes, may also produce ET-1. <sup><xref rid="B31" ref-type="bibr">31</xref> , <xref rid="B32" ref-type="bibr">32</xref> </sup> By upregulating the expression of adhesive molecules, ET-1 could induce the adherence of neutrophils to coronary artery endothelial cells and myocardium cells. <sup><xref rid="B33" ref-type="bibr">33</xref></sup> In addition, elevated ET -1 is associated with the enhancement of oxidative stress and the activation of various inflammatory factors in the inflammation cascade, which contribute to the formation, aggravation, and rupture of atherosclerotic plaques. <sup><xref rid="B34" ref-type="bibr">34</xref> , <xref rid="B35" ref-type="bibr">35</xref> </sup> Finally, previous studies have revealed the relation of ET-1 with reperfusion injury, microvascular obstruction, coronary collateral circulation formation, coronary artery calcification, and vascular and myocardial remodeling. <sup><xref rid="B7" ref-type="bibr">7</xref> - <xref rid="B9" ref-type="bibr">9</xref> , <xref rid="B24" ref-type="bibr">24</xref> , <xref rid="B36" ref-type="bibr">36</xref> </sup> Additionally, ET-1 has proven to be associated with promoted platelet aggregation and an activated prothrombotic state. <sup><xref rid="B7" ref-type="bibr">7</xref> , <xref rid="B37" ref-type="bibr">37</xref> </sup> All of these might contribute to the progression of atherosclerotic lesions.</p>
        <p>In the present study, subgroup analysis demonstrated a consistent relation between the plasma big ET-1 level and the SS. This positive correlation between big ET-1 and CAD severity provides new ideas for clinical practice. The plasma big ET-1 level could act as a useful marker for predicting the severity of CAD in patients with NSTEMI, which might aid in the prognostic evaluation and management guidance. On the other hand, several trials have tried to explore the efficacy and safety of endothelin receptor antagonists in patients with atherosclerosis. <sup><xref rid="B8" ref-type="bibr">8</xref> , <xref rid="B38" ref-type="bibr">38</xref> </sup> Future studies could help further elucidate the exact pathophysiological mechanisms of ET-1 in NSTEMI and provide more evidence for the prevention and treatment of atherosclerosis.</p>
        <p>Several limitations need to be noted in this study. First, the present study was a cross-sectional study with inherent defects. The relation between the plasma big ET-1 level and the SS could only be inferred as correlative, rather than causal. Meanwhile, the discrimination of big ET-1 was only moderate. It is necessary to test this biomarker in future clinical trials in order to apply it in routine clinical settings. In this cross-sectional study, medications before myocardial infarction might be more important. However, due to patients&#8217; recall bias and missing data, accurate data about medications before myocardial infarction could not be acquired. As an alternative, we have displayed medications after myocardial infarction. Second, although multivariate logistic regression has been performed to adjust for potential confounders, the association between big ET-1 and the SS might be confounded by other unmeasured factors. Third, this study was undertaken in the Chinese population from a single center. Therefore, the results should be extrapolated to other populations with caution. In addition, the sample size was relatively small, which might limit the statistical power. Finally, we have only measured the plasma big ET-1 level at baseline but lack serial data of big ET-1 concentrations. Dynamic monitoring of plasma big ET-1 levels might provide more information about the severity of CAD.</p>
      </sec>
      <sec sec-type="conclusions">
        <title>Conclusion</title>
        <p>The plasma big ET-1 level was significantly correlated with the severity of CAD in patients with NSTEMI, as assessed by the SS. A high plasma big ET-1 level was an independent predictor for intermediate-high SS.</p>
      </sec>
    </body>
    <back>
      <fn-group>
        <fn fn-type="other">
          <p>Study association</p>
          <p>This study is not associated with any thesis or dissertation work.</p>
        </fn>
        <fn fn-type="other">
          <p>Ethics approval and consent to participate</p>
          <p>This study was approved by the Ethics Committee of the Fuwai Hospital under the protocol number 2017-1203. All the procedures in this study were in accordance with the 1975 Helsinki Declaration, updated in 2013. Informed consent was obtained from all participants included in the study.</p>
        </fn>
        <fn id="fn_ast1001">
          <label> * </label>
          <p>Supplemental Materials</p>
        </fn>
        <fn id="fn6001">
          <label/>
          <p>For additional information, please click here.</p>
        </fn>
      </fn-group>
      <fn-group>
        <fn fn-type="financial-disclosure" id="fn7001">
          <p>Sources of funding: This study was partially funded by National Key Research and Develop Program of China (number 2017YFC0908802)</p>
        </fn>
      </fn-group>
    </back>
  </sub-article>
</article>
