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  <front>
    <journal-meta>
      <journal-id journal-id-type="nlm-ta">Arq Bras Cardiol</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</publisher-name>
      </publisher>
    </journal-meta>
    <article-meta>
      <article-id pub-id-type="publisher-id" specific-use="scielo-v3">4qQRHmkY3QVF9fYdcvhjtKg</article-id>
      <article-id pub-id-type="publisher-id" specific-use="scielo-v2">S0066-782X2015000100015</article-id>
      <article-id pub-id-type="other">00015</article-id>
      <article-id pub-id-type="doi">10.5935/abc.20140208</article-id>
      <article-categories>
        <subj-group subj-group-type="heading">
          <subject>Case Report</subject>
        </subj-group>
      </article-categories>
      <title-group>
        <article-title>Pseudo-pulmonary Embolism &#8211; A Case of Hypoxemia Associated with Right-to-left Shunt</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <name>
            <surname>Faustino</surname>
            <given-names>Mariana</given-names>
          </name>
          <xref ref-type="aff" rid="aff01">1</xref>
          <xref ref-type="corresp" rid="c01"/>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Soares</surname>
            <given-names>Ana Oliveira</given-names>
          </name>
          <xref ref-type="aff" rid="aff01">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Rodrigues</surname>
            <given-names>Fernando</given-names>
          </name>
          <xref ref-type="aff" rid="aff02">2</xref>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Anjos</surname>
            <given-names>Rui</given-names>
          </name>
          <xref ref-type="aff" rid="aff03">3</xref>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Freitas</surname>
            <given-names>Ant&#243;nio</given-names>
          </name>
          <xref ref-type="aff" rid="aff01">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Gil</surname>
            <given-names>Victor M.</given-names>
          </name>
          <xref ref-type="aff" rid="aff01">1</xref>
        </contrib>
      </contrib-group>
      <aff id="aff01">
        <label>1</label>
        <institution content-type="orgname">Hospital Professor Fernando Fonseca</institution>
        <addr-line>
          <named-content content-type="city">Lisboa</named-content>
        </addr-line>
        <country>Portugal</country>
        <institution content-type="original">Servi&#231;o de Cardiologia, Hospital Professor Fernando Fonseca, Lisboa &#8722; Portugal</institution>
      </aff>
      <aff id="aff02">
        <label>2</label>
        <institution content-type="orgname">Hospital Professor Fernando Fonseca</institution>
        <addr-line>
          <named-content content-type="city">Lisboa</named-content>
        </addr-line>
        <country>Portugal</country>
        <institution content-type="original">Amadora; Servi&#231;o de Pneumologia, Hospital Professor Fernando Fonseca, Lisboa &#8722; Portugal</institution>
      </aff>
      <aff id="aff03">
        <label>3</label>
        <institution content-type="orgname">Centro Hospitalar de Lisboa Ocidental</institution>
        <institution content-type="orgdiv1">Hospital de Santa Cruz</institution>
        <addr-line>
          <named-content content-type="city">Lisboa</named-content>
        </addr-line>
        <country>Portugal</country>
        <institution content-type="original">Amadora; Servi&#231;o de Cardiologia Pedi&#225;trica, Hospital de Santa Cruz, Centro Hospitalar de Lisboa Ocidental, Lisboa &#8722; Portugal</institution>
      </aff>
      <author-notes>
        <corresp id="c01"><bold>Mailing Address: Mariana Faustino</bold>. Avenida Marqu&#234;s de Tomar, 89 6&#186;A. Postal Code: 1050-154, Lisboa &#8722; Portugal. E-mail:   <email>marianafaustino85@gmail.com</email></corresp>
        <fn fn-type="con">
          <p>
            <bold>Author contributions</bold>
          </p>
          <p>Conception and design of the research: Faustino M; Soares AO; Freitas A; Gil VM; Acquisition of data: Faustino M; Soares AO; Freitas A; Analysis and interpretation of the data: Faustino M; Soares AO; Rodrigues F; Anjos R; Freitas A; Gil VM; Writing of the manuscript: Faustino M; Critical revision of the manuscript for intellectual content: Faustino M; Soares AO; Freitas A; Gil VM.</p>
        </fn>
        <fn fn-type="conflict">
          <p>
            <bold>Potential Conflict of Interest</bold>
          </p>
          <p>No potential conflict of interest relevant to this article was reported.</p>
        </fn>
      </author-notes>
      <pub-date pub-type="epub-ppub">
        <month>01</month>
        <year>2015</year>
      </pub-date>
      <volume>104</volume>
      <issue>1</issue>
      <fpage>e4</fpage>
      <lpage>e9</lpage>
      <history>
        <date date-type="received">
          <day>29</day>
          <month>10</month>
          <year>2013</year>
        </date>
        <date date-type="rev-recd">
          <day>22</day>
          <month>01</month>
          <year>2014</year>
        </date>
        <date date-type="accepted">
          <day>22</day>
          <month>01</month>
          <year>2014</year>
        </date>
      </history>
      <permissions>
        <license license-type="open-access" xlink:href="http://creativecommons.org/licenses/by-nc/3.0/">
          <license-p>This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.</license-p>
        </license>
      </permissions>
      <kwd-group xml:lang="en">
        <kwd>Dyspnea</kwd>
        <kwd>Echocardiography</kwd>
        <kwd>Transesophageal</kwd>
        <kwd>Heart Septal Defects</kwd>
        <kwd>Atrial</kwd>
      </kwd-group>
      <counts>
        <fig-count count="14"/>
        <table-count count="0"/>
        <equation-count count="0"/>
        <ref-count count="9"/>
        <page-count count="6"/>
      </counts>
    </article-meta>
  </front>
  <body>
    <sec sec-type="intro">
      <title>Introduction</title>
      <p>Platypnea orthodeoxia is a rare syndrome characterized by dyspnea and decreased arterial oxygen saturation when passing from the dorsal decubitus position to the sitting or upright position<xref ref-type="bibr" rid="B01">1</xref>. It usually results from an intracardiac right-to-left shunt; however, the pathophysiological mechanism responsible for the positional nature of the shunt has not been clarified<xref ref-type="bibr" rid="B01">1</xref><sup>,</sup><xref ref-type="bibr" rid="B02">2</xref>. We report a case of dyspnea and orthostatic hypoxemia, which was attributed to a right-to-left shunt due to atrial septal defect (ASD).</p>
    </sec>
    <sec sec-type="cases">
      <title>Case Report</title>
      <p>The patient is a 75-year-old male with no relevant personal antecedents. He underwent elective right hip arthroplasty, and, on the fourth postoperative day, after beginning to walk, dyspnea, polypnea and low arterial oxygen saturation appeared.</p>
      <p>His physical examination findings were as follows: arterial blood pressure 120/70 mm Hg; heart rate 68 bpm; respiratory rate 30 bpm; peripheral saturation 80%. His cardiac and pulmonary auscultations were uneventful, and neither jugular venous distention nor peripheral edema was observed.</p>
      <p>Regarding laboratory findings, his blood gas analysis (under supplementary oxygen at 5 L/minute) stood out, with an arterial oxygen partial pressure (PaO<sub>2</sub>) of 47 mm Hg and respiratory alkalosis. Relevant changes were observed in neither hematological nor biochemical parameters. The electrocardiogram and chest X-ray showed no significant changes.</p>
      <p>Chest computed tomography angiography (CT-angio) revealed small and hypodense filling defects in the middle and right inferior lobar arteries, in addition to slight dilation of the ascending aorta (45 mm).</p>
      <p>The transthoracic echocardiogram findings were as follows: cardiac chambers of normal dimensions; good left and right ventricular function; minimum tricuspid regurgitation; no pulmonary hypertension; exuberant Eustachian valve; slightly dilation of the aortic root and ascending aorta (45 mm). No ASD was identified.</p>
      <p>Pulmonary embolism was diagnosed and enoxaparin therapy initiated. Periods of hypoxemia related to the sitting position persisted, and total normalization of peripheral saturation was obtained with the dorsal decubitus position.</p>
      <p>Considering the hypothesis of intracardiac right-to-left shunt, transesophageal echocardiogram (TEE) with agitaded saline contrast was performed, revealing exuberant atrial septal (AS) aneurysm of the <italic>ostium secundum</italic> type, allowing the contrast medium to pass to the left chambers, even with no Valsalva maneuver (<xref ref-type="fig" rid="f01">Figure 1A</xref>).</p>
      <fig id="f01">
        <label>Figure 1</label>
        <caption>
          <title>(A) Transesophageal echocardiogram in the dorsal decubitus position (0&#186;) showing an exuberant atrial septal aneurysm with right-to-left shunt (arrow) evidenced on color Doppler and contrast medium flow; (B) Transesophageal echocardiogram on the tilt table (60&#176;) with increased right-to-left flow evidenced on color Doppler and contrast medium flow.</title>
        </caption>
        <graphic xlink:href="1678-4170-abc-104-01-00e4-40208-gf01.tif"/></fig>
      <p>In an attempt to clarify the positional variation of arterial oxygen saturation, TEE was also performed on a tilt table, under serial blood gas monitoring. At 60&#186;, the prolapse of the AS aneurysm to the left atrium was maintained, and the contrast flow to the left chambers was immediate and greater than that observed in the decubitus position (<xref ref-type="fig" rid="f01">Figure 1B</xref>). Concomitantly, PaO<sub>2</sub> decreased from an initial value of 67 mm Hg, in the decubitus position, to 43 mm Hg (under normal conditions).</p>
      <p>After one week, the patient underwent a new high-resolution CT-angio, which showed no filling defects in the pulmonary circulation, and the review of the previous exam raised the possibility of a false-positive exam. Pulmonary ventilation/ perfusion scan showed neither perfusion nor diffusion defects, and the functional respiratory tests showed no obstructive, restrictive or diffusion changes.</p>
      <p>The patient underwent percutaneous ASD closure by placement of a cribriform device under fluoroscopic and intracardiac echography control.</p>
      <p>The TEE with agitated saline was repeated and showed a well-positioned device adjacent to the AS aneurysm, with persistence of the right-to-left contrast medium flow at a lower degree than in the previous exam, and almost exclusively associated with the Valsalva maneuver. That flow did not increase at the 60&#186; position on the tilt table; however, a PaO<sub>2</sub> reduction from 102 mm Hg to 75 mm Hg was observed (<xref ref-type="fig" rid="f02">Figure 2</xref>).</p>
      <fig id="f02">
        <label>Figure 2</label>
        <caption>
          <title>Transesophageal echocardiogram after closure of the atrial septal defect, showing the occlusion device (arrow), adjacent to the atrial septal aneurysm and persistence of the contrast medium flow.</title>
        </caption>
        <graphic xlink:href="1678-4170-abc-104-01-00e4-40208-gf02.tif"/></fig>
    </sec>
    <sec sec-type="discussion">
      <title>Discussion</title>
      <p>This is the report of a case of platypnea orthodeoxia caused by an ASD with right-to-left shunt and no evidence of pulmonary hypertension in a patient previously diagnosed with pulmonary embolism.</p>
      <p>Platypnea can result from several cardiopulmonary processes, but its most frequent cause is a right-to-left interatrial shunt through a patent <italic>foramen ovale</italic> or, more rarely, a true ASD in the absence of pulmonary hypertension. Although frequent (persistence of patent <italic>foramen ovale</italic> in 27% of the population), those ASDs are usually asymptomatic<xref ref-type="bibr" rid="B03">3</xref>. Under normal conditions, presence of overload of the right chambers and pulmonary blood flows from the left side to the right side, according to hypertension, and can also occur under specific circumstances, the pressure gradient. Thus, a right-to-left shunt appears in the such as the Valsalva maneuver<xref ref-type="bibr" rid="B01">1</xref><sup>,</sup><xref ref-type="bibr" rid="B04">4</xref>.</p>
      <p>The physiological mechanism of the positional nature of the shunt has not been fully clarified. In platypnea orthodeoxia, the pulmonary arterial pressure is typically not increased, but, in the upright position, one or more anatomical and functional factors can change the physiological flow direction<xref ref-type="bibr" rid="B01">1</xref><sup>,</sup><xref ref-type="bibr" rid="B05">5</xref><sup>,</sup><xref ref-type="bibr" rid="B06">6</xref>.</p>
      <p>Dilation of the ascending aorta is a frequently cited pathophysiological mechanism<xref ref-type="bibr" rid="B03">3</xref>. In the upright position, the effect of gravity on the dilated aortic root leads to the forward and downward displacement of that vessel, resulting in elevation of the right atrial pressure and stretching of the AS, with enlargement of the ASD orifice<xref ref-type="bibr" rid="B02">2</xref>,<xref ref-type="bibr" rid="B06">6</xref>. It also contributes to AS horizontalization, directing the blood flow from the inferior vena cava preferentially to the AS orifice. Other factors, such as kyphoscoliosis and pneumonectomy, contribute to AS horizontalization<xref ref-type="bibr" rid="B06">6</xref>,<xref ref-type="bibr" rid="B07">7</xref>.</p>
      <p>Persistence of the Eustachian valve also contributes to direct blood flow from the inferior vena cava to the AS orifice, as reminiscence of its intrauterine function<xref ref-type="bibr" rid="B02">2</xref>. The AS aneurysm disturbs the laminar blood flow on the AS, making it turbulent, and directs it to the ASD orifice<xref ref-type="bibr" rid="B08">8</xref>.</p>
      <p>In the case here reported, the ascending aorta dilation developed over time, the voluminous AS aneurysm, and the prominent Eustachian valve might have played an important role in the pathophysiology of platypnea orthodeoxia.</p>
      <p>On the other hand, even in the absence of pulmonary hypertension, conditions causing a localized increase in right atrial pressure and/or a reduction in the compliance of right chambers, such as pulmonary embolism, constrictive pericarditis, pericardial effusion, tricuspid stenosis, right atrial myxoma, and right ventricular dysfunction, play a role in the etiology of right-to-left shunt<xref ref-type="bibr" rid="B05">5</xref><sup>,</sup><xref ref-type="bibr" rid="B06">6</xref><sup>,</sup><xref ref-type="bibr" rid="B09">9</xref>.</p>
      <p>Initially, the hypothesis of pulmonary embolism was considered for our patient, but that diagnosis was not confirmed later. However, a small pulmonary embolism, totally resolved with anticoagulant therapy, could have been the factor revealing the clinical findings of platypnea orthodeoxia.</p>
      <p>In that case, the patient&#8217;s degrees of dyspnea and hypoxemia were not in accordance with the hemodynamic stability and lack of echographic signs of overload of the right chambers, and that diagnosis would be insufficient to explain the positional variations of saturation, raising the suspicion of another concomitant process. The CT-angio suggestion of peripheral pulmonary embolism of the distal pulmonary artery branches should be considered with reserve, because of the low resolution of that exam for such diagnosis, contrarily to that which occurs for major trunks.</p>
      <p>This case evidences the need for a high index of suspicion to establish the diagnosis of platynea orthodeoxia, and it should be considered in the differential diagnosis of unexplained or non-totally explained hypoxemia.</p>
      <p>Platypnea orthodeoxia was first described in 1949, and 228 cases have been reported, of which, 215 have an intracardiac origin. However, it might still be underdiagnosed<xref ref-type="bibr" rid="B01">1</xref><sup>,</sup><xref ref-type="bibr" rid="B04">4</xref>.</p>
      <p>Its therapy implies either percutaneous or surgical ASD closure; the former is used in approximately 75% of the cases reported, although the latter is more effective, mainly for fenestrated ASD and complex defects<xref ref-type="bibr" rid="B04">4</xref>. However, the decision to intervene depends on the severity of symptoms and morbidities associated. In our case, the defect closure was not complete: the right-to-left shunt and of the PaO<sub>2</sub> reduction associated with the upright position persisted, although to a lesser extent and asymptomatic.</p>
      <p>In addition, this case showed the usefulness of the TEE performed on a tilt table to establish the correlation between PaO<sub>2</sub> and the anatomical and functional changes induced by the upright position on the atrium.</p>
      <fig id="f03">
        <label>Video 1</label>
        <caption>
          <title>Transesophageal echocardiogram in the dorsal decubitus position (0&#186;) showing an exuberant atrial septal aneurysm with right-to-left flow evidenced on color Doppler.</title>
        </caption>
        <media xlink:href="https://minio.scielo.br/documentstore/1678-4170/4qQRHmkY3QVF9fYdcvhjtKg/58d677a6d349556e123bd8b29fefb689338fc930.mp4" mimetype="video" mime-subtype="mp4"/>
      </fig>
      <fig id="f04">
        <label>Video 2</label>
        <caption>
          <title>Transesophageal echocardiogram with agitated saline in the dorsal decubitus position (0&#186;) showing an atrial septal aneurysm with right-to-left contrast medium flow.</title>
        </caption>
        <media xlink:href="https://minio.scielo.br/documentstore/1678-4170/4qQRHmkY3QVF9fYdcvhjtKg/ffde6b8316d8d5e6192bd103b36c5c8d19ecc76f.mp4" mimetype="video" mime-subtype="mp4"/>
      </fig>
      <fig id="f05">
        <label>Video 3</label>
        <caption>
          <title>Transesophageal echocardiogram on the tilt table at 60&#186;: prolapse of the atrial septal aneurysm to the left atrium was maintained, and increased right-to-left contrast medium flow as compared to that in the decubitus position.</title>
        </caption>
        <media xlink:href="https://minio.scielo.br/documentstore/1678-4170/4qQRHmkY3QVF9fYdcvhjtKg/e2051595de46ac53d989aebd21ed89904ecf3c70.mp4" mimetype="video" mime-subtype="mp4"/>
      </fig>
      <fig id="f06">
        <label>Video 4</label>
        <caption>
          <title>Transesophageal echocardiogram with agitated saline on the tilt table at 60&#186;: increased right-to-left contrast medium flow as compared to that in the decubitus position.</title>
        </caption>
        <media xlink:href="https://minio.scielo.br/documentstore/1678-4170/4qQRHmkY3QVF9fYdcvhjtKg/9c7ea8aa0454b068d60a70d235ade42e4d8ad17f.mp4" mimetype="video" mime-subtype="mp4"/>
      </fig>
      <fig id="f07">
        <label>Video 5</label>
        <caption>
          <title>Transesophageal echocardiogram with agitated saline after atrial septal defect closure: occlusion device adjacent to the atrial septal aneurysm, and persistent but reduced right-to-left contrast medium flow.</title>
        </caption>
        <media xlink:href="https://minio.scielo.br/documentstore/1678-4170/4qQRHmkY3QVF9fYdcvhjtKg/0cc0d65c839dce54644267a2bd140be510304dbd.mp4" mimetype="video" mime-subtype="mp4"/>
      </fig>
    </sec>
  </body>
  <back>
    <fn-group>
      <fn fn-type="supported-by">
        <p>
          <bold>Sources of Funding</bold>
        </p>
        <p>There were no external funding sources for this study.</p>
      </fn>
      <fn fn-type="other">
        <p>
          <bold>Study Association</bold>
        </p>
        <p>This study is not associated with any thesis or dissertation work.</p>
      </fn>
    </fn-group>
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  </back>
  <sub-article article-type="translation" id="SA1" xml:lang="pt">
    <front-stub>
      <article-categories>
        <subj-group subj-group-type="heading">
          <subject>Relato de Caso</subject>
        </subj-group>
      </article-categories>
      <title-group>
        <article-title>Pseudoembolia Pulmonar &#8211; Um Caso de Hipoxemia Associada a Shunt Direito-esquerdo</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <name>
            <surname>Faustino</surname>
            <given-names>Mariana</given-names>
          </name>
          <xref ref-type="aff" rid="aff04">1</xref>
          <xref ref-type="corresp" rid="c02"/>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Soares</surname>
            <given-names>Ana Oliveira</given-names>
          </name>
          <xref ref-type="aff" rid="aff04">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Rodrigues</surname>
            <given-names>Fernando</given-names>
          </name>
          <xref ref-type="aff" rid="aff05">2</xref>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Anjos</surname>
            <given-names>Rui</given-names>
          </name>
          <xref ref-type="aff" rid="aff06">3</xref>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>Freitas</surname>
            <given-names>Ant&#243;nio</given-names>
          </name>
          <xref ref-type="aff" rid="aff04">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <name>
            <surname>M. Gil</surname>
            <given-names>Victor</given-names>
          </name>
          <xref ref-type="aff" rid="aff04">1</xref>
        </contrib>
      </contrib-group>
      <aff id="aff04">
        <label>1</label>
        <institution content-type="orgname">Hospital Professor Fernando Fonseca</institution>
        <addr-line>
          <named-content content-type="city">Lisboa</named-content>
        </addr-line>
        <country>Portugal</country>
        <institution content-type="original">Servi&#231;o de Cardiologia, Hospital Professor Fernando Fonseca, Lisboa &#8722; Portugal</institution>
      </aff>
      <aff id="aff05">
        <label>2</label>
        <institution content-type="orgname">Hospital Professor Fernando Fonseca</institution>
        <addr-line>
          <named-content content-type="city">Lisboa</named-content>
        </addr-line>
        <country>Portugal</country>
        <institution content-type="original">Amadora; Servi&#231;o de Pneumologia, Hospital Professor Fernando Fonseca, Lisboa &#8722; Portugal</institution>
      </aff>
      <aff id="aff06">
        <label>3</label>
        <institution content-type="orgname">Centro Hospitalar de Lisboa Ocidental</institution>
        <institution content-type="orgdiv1">Hospital de Santa Cruz</institution>
        <addr-line>
          <named-content content-type="city">Lisboa</named-content>
        </addr-line>
        <country>Portugal</country>
        <institution content-type="original">Amadora; Servi&#231;o de Cardiologia Pedi&#225;trica, Hospital de Santa Cruz, Centro Hospitalar de Lisboa Ocidental, Lisboa &#8722; Portugal</institution>
      </aff>
      <author-notes>
        <corresp id="c02"><bold>Correspond&#234;ncia: Mariana Faustino</bold>. Avenida Marqu&#234;s de Tomar, 89 6&#186;A. CEP 1050-154, Lisboa &#8722; Portugal. E-mail:   <email>marianafaustino85@gmail.com</email></corresp>
        <fn fn-type="con">
          <p>
            <bold>Contribui&#231;&#227;o dos autores</bold>
          </p>
          <p>Concep&#231;&#227;o e desenho da pesquisa: Faustino M; Soares AO; Freitas A; Gil VM; Obten&#231;&#227;o de dados: Faustino M; Soares AO; Freitas A; An&#225;lise e interpreta&#231;&#227;o dos dados: Faustino M; Soares AO; Rodrigues F; Anjos R; Freitas A; Gil VM; Reda&#231;&#227;o do manuscrito: Faustino M; Revis&#227;o cr&#237;tica do manuscrito quanto ao conte&#250;do intelectual importante: Faustino M; Soares AO; Freitas A; Gil VM.</p>
        </fn>
        <fn fn-type="conflict">
          <p>
            <bold>Potencial conflito de interesse</bold>
          </p>
          <p>Declaro n&#227;o haver conflito de interesses pertinentes.</p>
        </fn>
      </author-notes>
      <kwd-group xml:lang="pt">
        <kwd>Dispneia</kwd>
        <kwd>Ecocardiografia Transesofagiana</kwd>
        <kwd>Comunica&#231;&#227;o Interatrial</kwd>
      </kwd-group>
    </front-stub>
    <body>
      <sec sec-type="intro">
        <title>Introdu&#231;&#227;o</title>
        <p>A platipneia ortodeoxia &#233; um s&#237;ndrome rara caracterizada por dispneia e pela diminui&#231;&#227;o da satura&#231;&#227;o arterial de oxig&#234;nio, com a passagem da posi&#231;&#227;o de dec&#250;bito para a posi&#231;&#227;o sentada ou ortost&#225;tica<xref ref-type="bibr" rid="B01">1</xref>. Resulta de um <italic>shunt</italic> direito-esquerdo, geralmente intracard&#237;aco; contudo, o mecanismo fisiopatol&#243;gico respons&#225;vel pela natureza posicional do   <italic>shunt</italic> n&#227;o est&#225; totalmente esclarecido <xref ref-type="bibr" rid="B01">1</xref><sup>,</sup><xref ref-type="bibr" rid="B02">2</xref>. Os autores descrevem um caso de dispneia e hipoxemia em ortostatismo, o qual foi atribu&#237;do a um   <italic>shunt</italic> direito-esquerdo por uma Comunica&#231;&#227;o Interauricular (CIA).</p>
      </sec>
      <sec sec-type="cases">
        <title>Relato do Caso</title>
        <p>Homem de 75 anos, sem antecedentes pessoais relevantes. Foi submetido eletivamente &#224; artroplastia da anca direita e, no quarto dia p&#243;s-operat&#243;rio, ap&#243;s come&#231;ar a deambular, iniciou dispneia, polipneia e baixa satura&#231;&#227;o arterial de oxig&#234;nio.</p>
        <p>No exame objetivo, apresentava tens&#227;o arterial de 120/70 mmHg, frequ&#234;ncia card&#237;aca de 68/minuto, frequ&#234;ncia respirat&#243;ria de 30/minuto, satura&#231;&#227;o perif&#233;rica de 80%. N&#227;o apresentava altera&#231;&#245;es na ausculta card&#237;aca e pulmonar, e nem ingurgitamento jugular e edemas perif&#233;ricos.</p>
        <p>Nas an&#225;lises, destacava-se gasometria (sob oxig&#234;nio suplementar a 5 L/minuto), com Press&#227;o Arterial Parcial de Oxig&#234;nio (PaO<sub>2</sub>) de 47 mmHg e alcalose respirat&#243;ria. N&#227;o apresentava altera&#231;&#245;es relevantes nos par&#226;metros hematol&#243;gicos e bioqu&#237;micos. O eletrocardiograma e a radiografia de t&#243;rax n&#227;o revelaram altera&#231;&#245;es relevantes.</p>
        <p>Realizou angiotomografia computorizada (angio-TC) de t&#243;rax, que revelou pequenos defeitos de reple&#231;&#227;o e hipodensos, nas art&#233;rias lobar m&#233;dia e lobar inferior direita. Revelou tamb&#233;m dilata&#231;&#227;o ligeira da aorta ascendente (45 mm).</p>
        <p>O ecocardiograma transtor&#225;cico mostrou cavidades de dimens&#245;es normais, com boa fun&#231;&#227;o dos ventr&#237;culos esquerdo e direito, regurgita&#231;&#227;o tric&#250;spide m&#237;nima, sem hipertens&#227;o pulmonar; v&#225;lvula de Eust&#225;quio exuberante; e raiz da aorta e aorta ascendente ligeiramente dilatadas (45 mm). N&#227;o se visualizou qualquer CIA.</p>
        <p>Foi admitido o diagn&#243;stico de embolia pulmonar e iniciada terap&#234;utica com enoxaparina. Persistiram per&#237;odos de hipoxemia, que se relacionaram com a posi&#231;&#227;o sentada, verificando-se total normaliza&#231;&#227;o da satura&#231;&#227;o perif&#233;rica quando o paciente se posicionava em dec&#250;bito.</p>
        <p>Considerando a hip&#243;tese de <italic>shunt</italic> intracard&#237;aco direito-esquerdo, realizou-se Ecocardiograma Transesof&#225;gico (ETE) com soro agitado, que revelou aneurisma exuberante do Septo Interauricular (SIA), com solu&#231;&#227;o de continuidade do tipo <italic>ostium secundum</italic>, permitindo a passagem de contraste para as cavidades esquerdas, mesmo sem manobra de Valsalva (<xref ref-type="fig" rid="f08">Figura 1A</xref>).</p>
        <fig id="f08">
          <label>Figura 1</label>
          <caption>
            <title>(A) Ecocardiograma transesof&#225;gico em dec&#250;bito (0&#186;) mostrando exuberante aneurisma do septo interauricular com shunt direito-esquerdo (seta) evidenciado por Doppler-cor e fluxo de contraste; (B) Ecocardiograma transesof&#225;gico na mesa tilt (60&#176;) com aumento do fluxo direito-esquerdo, evidenciado por Doppler colorido e contraste.</title>
          </caption>
          <graphic xlink:href="1678-4170-abc-104-01-00e4-40208-gf01-pt.tif"/></fig>
        <p>Para esclarecimento da varia&#231;&#227;o posicional da satura&#231;&#227;o arterial de oxig&#234;nio, o ETE tamb&#233;m foi realizado na mesa <italic>tilt</italic>, sob monitoriza&#231;&#227;o gasom&#233;trica seriada. A 60&#186; verificou-se procid&#234;ncia mantida do aneurisma do SIA para a aur&#237;cula esquerda, al&#233;m de passagem de contraste para as cavidades esquerdas imediata e mais abundante em rela&#231;&#227;o ao que foi observado em dec&#250;bito (<xref ref-type="fig" rid="f08">Figura 1B</xref>) Concomitantemente, verificou-se descida da PaO<sub>2</sub>, de um valor inicial de 67 mmHg, em dec&#250;bito, para 43 mmHg (ar ambiente).</p>
        <p>Ap&#243;s 1 semana, o paciente repetiu tomografia computadorizada de alta resolu&#231;&#227;o, que n&#227;o mostrou defeitos de reple&#231;&#227;o na circula&#231;&#227;o pulmonar, e a revis&#227;o do exame pr&#233;vio conduziu &#224; possibilidade de um falso-positivo. A cintigrafia de ventila&#231;&#227;o perfus&#227;o n&#227;o mostrou defeitos da perfus&#227;o e nem da difus&#227;o, e as provas funcionais respirat&#243;rias n&#227;o mostraram altera&#231;&#245;es obstrutivas, restritivas ou da difus&#227;o.</p>
        <p>O paciente foi submetido ao fechamento da CIA, por via percut&#226;nea, com coloca&#231;&#227;o de dispositivo cribiforme, sob controle fluorosc&#243;pico e de ecografia intracard&#237;aca.</p>
        <p>Repetiu ETE com soro agitado, que mostrou dispositivo bem posicionado adjacente ao aneurisma do SIA, persistindo o fluxo de contraste direito-esquerdo, em muito menor grau do que no exame pr&#233;vio, e quase que exclusivamente associado &#224; manobra de Valsalva. Esse fluxo n&#227;o se acentuou quando posicionado a 60&#186; na mesa   <italic>tilt</italic>, contudo verificou-se redu&#231;&#227;o da PaO<sub>2</sub> de 102 mmHg para 75 mmHg (<xref ref-type="fig" rid="f09">Figura 2</xref>).</p>
        <fig id="f09">
          <label>Figura 2</label>
          <caption>
            <title>Ecocardiograma transesof&#225;gico ap&#243;s o fechamento de comunica&#231;&#227;o interauricular, mostrando o dispositivo de oclus&#227;o (seta), adjacente ao aneurisma do septo interauricular e a persist&#234;ncia de fluxo de contraste.</title>
          </caption>
          <graphic xlink:href="1678-4170-abc-104-01-00e4-40208-gf02-pt.tif"/></fig>
      </sec>
      <sec sec-type="discussion">
        <title>Discuss&#227;o</title>
        <p>Os autores descrevem um caso de platipneia ortodeoxia causado por uma CIA com   <italic>shunt</italic> direito-esquerdo, sem evid&#234;ncia de hipertens&#227;o pulmonar, num paciente com suspeita diagn&#243;stica pr&#233;via de embolia pulmonar.</p>
        <p>A platipneia pode resultar de v&#225;rios processos cardiopulmonares, mas a causa mais frequente &#233; a exist&#234;ncia de um <italic>shunt</italic> interauricular direito-esquerdo, atrav&#233;s de um forame ovale patente ou, mais raro, um verdadeiro defeito do SIA, na aus&#234;ncia de hipertens&#227;o pulmonar. Embora essas comunica&#231;&#245;es interauriculares sejam frequentes (persist&#234;ncia de forame ovale patente em 27% da popula&#231;&#227;o), elas geralmente s&#227;o assintom&#225;ticas<xref ref-type="bibr" rid="B03">3</xref>. Em condi&#231;&#245;es normais, o fluxo de sangue faz-se da esquerda para a direita, de acordo com o gradiente de press&#227;o. Assim, o <italic>shunt</italic>direito-esquerdo surge quando h&#225; sobrecarga das cavidades direitas e hipertens&#227;o pulmonar, podendo tamb&#233;m ocorrer em circunst&#226;ncias espec&#237;ficas, como na manobra de Valsalva<xref ref-type="bibr" rid="B01">1</xref><sup>,</sup><xref ref-type="bibr" rid="B04">4</xref>.</p>
        <p>O mecanismo fisiol&#243;gico respons&#225;vel pela natureza posicional do   <italic>shunt</italic> n&#227;o est&#225; totalmente esclarecido. Na platipneia ortodeoxia, n&#227;o h&#225;, tipicamente, aumento da press&#227;o arterial pulmonar, mas, em ortostatismo, haver&#225; um ou v&#225;rios fatores anat&#244;micos e funcionais, capazes de alterar a dire&#231;&#227;o do fluxo fisiol&#243;gic o<xref ref-type="bibr" rid="B01">1</xref><sup>,</sup><xref ref-type="bibr" rid="B05">5</xref><sup>,</sup><xref ref-type="bibr" rid="B06">6</xref>.</p>
        <p>A dilata&#231;&#227;o da aorta ascendente &#233; um dos mecanismos fisiopatol&#243;gicos mais frequentemente apontados<xref ref-type="bibr" rid="B03">3</xref>. Em ortostatismo, o efeito da gravidade sobre a raiz da aorta dilatada leva ao deslocamento desta para diante e para baixo, resultando na eleva&#231;&#227;o da press&#227;o na aur&#237;cula direita e no estiramento do SIA, com aumento da dimens&#227;o do orif&#237;cio de comunica&#231;&#227;o<xref ref-type="bibr" rid="B02">2</xref><sup>,</sup><xref ref-type="bibr" rid="B06">6</xref>. Contribui tamb&#233;m para a horizontaliza&#231;&#227;o do SIA, fazendo com que o fluxo proveniente da veia cava inferior se dirija preferencialmente para o orif&#237;cio comunicante do SIA. Outros mecanismos, como a cifoescoliose e pneumectomia, concorrem para a horizontaliza&#231;&#227;o do SIA<xref ref-type="bibr" rid="B06">6</xref><sup>,</sup><xref ref-type="bibr" rid="B07">7</xref>.</p>
        <p>A persist&#234;ncia da v&#225;lvula de Eust&#225;quio tamb&#233;m contribui para direcionar o fluxo da veia cava inferior para o orif&#237;cio do SIA, como reminisc&#234;ncia de sua fun&#231;&#227;o intrauterina<xref ref-type="bibr" rid="B02">2</xref>. O aneurisma do SIA perturba o fluxo laminar ao longo do SIA, tornando-o turbulento, e dirige-o para o orif&#237;cio comunicante<xref ref-type="bibr" rid="B08">8</xref>.</p>
        <p>No caso apresentado, a dilata&#231;&#227;o da aorta ascendente, que se ter&#225; vindo a desenvolver com o aumento da idade, o volumoso aneurisma do SIA e a proeminente v&#225;lvula de Eust&#225;quio tiveram, provavelmente, um papel importante na fisiopatologia da platipneia ortodeoxia.</p>
        <p>Por outro lado, mesmo na aus&#234;ncia de hipertens&#227;o pulmonar, as situa&#231;&#245;es que causam aumento de press&#227;o localizada na aur&#237;cula direita e/ou que diminuem a   <italic>compliance</italic> das cavidades direitas, como embolia pulmonar, pericardite constritiva, derrame peric&#225;rdico, estenose tric&#250;spide, mixoma auricular direito, disfun&#231;&#227;o ventricular direita, t&#234;m um papel na etiologia do   <italic>shunt</italic> direito-esquerdo<xref ref-type="bibr" rid="B05">5</xref><sup>,</sup><xref ref-type="bibr" rid="B06">6</xref><sup>,</sup><xref ref-type="bibr" rid="B09">9</xref>.</p>
        <p>Neste doente, inicialmente, foi considerada a hip&#243;tese de embolia pulmonar, diagn&#243;stico que n&#227;o se veio a confirmar. Contudo, uma embolia pulmonar de pequena dimens&#227;o, totalmente resolvida com terap&#234;utica anticoagulante, poderia ter sido o fator revelador do quadro cl&#237;nico de platipneia ortodeoxia.</p>
        <p>Neste caso, o grau de dispneia e hipoxemia do doente n&#227;o era concordante com a estabilidade hemodin&#226;mica e com a aus&#234;ncia de sinais ecogr&#225;ficos de sobrecarga das cavidades direitas, n&#227;o sendo esse diagn&#243;stico suficiente para explicar as varia&#231;&#245;es posicionais da satura&#231;&#227;o, o que levou &#224; suspei&#231;&#227;o de outro processo concomitante. A sugest&#227;o da angio-TC de embolia pulmonar perif&#233;rica, em consequ&#234;ncia de ramos distais da art&#233;ria pulmonar, deve ser encarada com reserva, dada &#224; baixa resolu&#231;&#227;o do exame para esse diagn&#243;stico, contrariamente ao que se sucede com os troncos principais.</p>
        <p>Este caso torna evidente a necessidade de um elevado &#237;ndice de suspei&#231;&#227;o para estabelecer o diagn&#243;stico de platineia ortodeoxia, devendo ser considerada no diagn&#243;stico diferencial da hipoxemia inexplicada ou n&#227;o totalmente explicada.</p>
        <p>A platipneia ortodeoxia foi descrita pela primeira vez em 1949, estando j&#225; referidos na literatura 228 casos, dos quais 215 de origem intracard&#237;aca. Ainda assim, est&#225; provavelmente subdiagnosticada<xref ref-type="bibr" rid="B01">1</xref><sup>,</sup><xref ref-type="bibr" rid="B04">4</xref>.</p>
        <p>A terap&#234;utica implica o fechamento do defeito do SIA, por via percut&#226;nea (utilizada em cerca de 75% dos casos descritos) ou cir&#250;rgica (mais eficaz, principalmente no caso de CIA fenestrada e de defeitos complexos)<xref ref-type="bibr" rid="B04">4</xref>. No entanto, a decis&#227;o de intervir depende da gravidade dos sintomas e das morbilidades associadas. Neste caso, o fechamento n&#227;o foi completo, persistindo quer o <italic>shunt</italic> direito-esquerdo, quer a diminui&#231;&#227;o da PaO<sub>2  </sub>associada ao ortostatismo, ainda que em menor grau e assintom&#225;ticos.</p>
        <p>Este caso ilustrou ainda a utilidade do ETE em mesa <italic>tilt</italic> para estabelecer a correla&#231;&#227;o entre a press&#227;o arterial de oxig&#234;nio e altera&#231;&#245;es anat&#244;micas e funcionais induzidas pelo ortostatismo sobre a aur&#237;cula.</p>
        <fig id="f10">
          <label>V&#237;deo 1</label>
          <caption>
            <title>Ecocardiograma transesof&#225;gico em dec&#250;bito 0&#186;: exuberante aneurisma do septo interauricular com fluxo direito-esquerdo por Doppler colorido.</title>
          </caption>
          <media xlink:href="https://minio.scielo.br/documentstore/1678-4170/4qQRHmkY3QVF9fYdcvhjtKg/58d677a6d349556e123bd8b29fefb689338fc930.mp4" mimetype="video" mime-subtype="mp4"/>
        </fig>
        <fig id="f11">
          <label>V&#237;deo 2</label>
          <caption>
            <title>Ecocardiograma transesof&#225;gico com soro agitado em dec&#250;bito 0&#186;: aneurisma do septo interauricular com fluxo de contraste direito-esquerdo.</title>
          </caption>
          <media xlink:href="https://minio.scielo.br/documentstore/1678-4170/4qQRHmkY3QVF9fYdcvhjtKg/ffde6b8316d8d5e6192bd103b36c5c8d19ecc76f.mp4" mimetype="video" mime-subtype="mp4"/>
        </fig>
        <fig id="f12">
          <label>V&#237;deo 3</label>
          <caption>
            <title>Ecocardiograma transesof&#225;gico em mesa basculante a 60&#186;: aneurisma do septo interauricular com procid&#234;ncia mantida para a &#225;trio esquerdo e aumento do fluxo de contraste direito-esquerdo, relativamente ao basal.</title>
          </caption>
          <media xlink:href="https://minio.scielo.br/documentstore/1678-4170/4qQRHmkY3QVF9fYdcvhjtKg/e2051595de46ac53d989aebd21ed89904ecf3c70.mp4" mimetype="video" mime-subtype="mp4"/>
        </fig>
        <fig id="f13">
          <label>V&#237;deo 4</label>
          <caption>
            <title>Ecocardiograma transesof&#225;gico com soro agitado em mesa basculante a 60&#186;: franco aumento do fluxo de contraste direito-esquerdo em rela&#231;&#227;o ao basal.</title>
          </caption>
          <media xlink:href="https://minio.scielo.br/documentstore/1678-4170/4qQRHmkY3QVF9fYdcvhjtKg/9c7ea8aa0454b068d60a70d235ade42e4d8ad17f.mp4" mimetype="video" mime-subtype="mp4"/>
        </fig>
        <fig id="f14">
          <label>V&#237;deo 5</label>
          <caption>
            <title>Ecocardiograma transesof&#225;gico com soro agitado ap&#243;s fechamento da comunica&#231;&#227;o interauricular: dispositivo de oclus&#227;o, adjacente ao aneurisma do septo interauricular e persist&#234;ncia de fluxo de contraste direito-esquerdo, em reduzida quantidade.</title>
          </caption>
          <media xlink:href="https://minio.scielo.br/documentstore/1678-4170/4qQRHmkY3QVF9fYdcvhjtKg/0cc0d65c839dce54644267a2bd140be510304dbd.mp4" mimetype="video" mime-subtype="mp4"/>
        </fig>
      </sec>
    </body>
    <back>
      <fn-group>
        <fn fn-type="supported-by">
          <p>
            <bold>Fontes de financiamento</bold>
          </p>
          <p>O presente estudo n&#227;o teve fontes de financiamento externas.</p>
        </fn>
        <fn fn-type="other">
          <p>
            <bold>Vincula&#231;&#227;o acad&#234;mica</bold>
          </p>
          <p>N&#227;o h&#225; vincula&#231;&#227;o deste estudo com disserta&#231;&#245;es e teses de p&#243;s-gradua&#231;&#227;o.</p>
        </fn>
      </fn-group>
    </back>
  </sub-article>
</article>
