Arq Bras Cardiol Arquivos Brasileiros de Cardiologia Arq. Bras. Cardiol. 0066-782X 1678-4170 Sociedade Brasileira de Cardiologia wGzjZCZ9rsD6Zvdjm3Mg7nG S0066-782X2014002200001 00001 10.5935/abc.20140154 Editorial Primary Angioplasty in the ACCEPT Registry: Why has it Been Difficult to Accept and Implement the Radial Artery Access as Preferential? Siqueira Dimytri Alexandre de Alvim 1 2 Brito Fabio Sandoli de Jr 3 Abizaid Alexandre A. C. 1 3 Instituto Dante Pazzanese de Cardiologia São Paulo SP Brasil Instituto Dante Pazzanese de Cardiologia, São Paulo, SP - Brasil. Hospital do Coração - ASS São Paulo SP Brasil Hospital do Coração - ASS, São Paulo, SP - Brasil. Hospital Israelita Albert Einstein São Paulo SP Brasil Hospital Israelita Albert Einstein, São Paulo, SP - Brasil. Mailing Address: Dimytri A. Siqueira. Avenida Dr. Dante Pazzanese, 500, Seção de Cardiologia Invasiva, Prédio III, 1º andar − Vila Mariana − Postal Code: 04012-909 − São Paulo, SP, Brasil 10 2014 103 4 268 271 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. Angioplasty Radial Artery Harm Reduction Fibrinolytic Agents Femoral Artery / complications

Obtaining arterial access is the initial and fundamental step of coronary intervention procedures. Since its first application for coronary angiography1 and percutaneous coronary intervention2, the radial approach has been known to have important clinical benefits, associated with a reduction in vascular and bleeding complications at the puncture site, and with early ambulation and greater patients' satisfaction as compared with the femoral approach. Recently, evidence from large randomized studies and meta-analyses3,4 has suggested that, for patients diagnosed with ST-segment elevation myocardial infarction (STEMI), the primary intervention via radial access is associated with a significant reduction in mortality rates and lower incidence of adverse cardiac events. Because of the consistency of those findings, international guidelines5 have recommended the radial approach for STEMI (class IIa, level of evidence B).

Incorporation of the radial access, however, has not been widespread, differing worldwide. More than 80% of the coronary interventions in France are performed via the radial artery approach. Data from the British Cardiovascular Intervention Society - National Institute for Clinical Outcomes Research (BCIS-NICOR)6 have indicated a rapid increase in the use of that approach in recent years, from 12.5% in 2006 to 49.5% in 2010. In the United States, however, only 16% of the interventions from 2007 to 2012 have used the radial artery access7. Until recently, brazilian data were scarse. According to the Brazilian Cardiovascular Intervention Center (Cenic), from 2005 to 2008, the radial access was used in 12.6% of the cases, and no significant increase has been observed in those years8. In a welcome and recently published article, Andrade et al.9 have reported an updated overview on the subject. They used data from a large Brazilian prospective and multicenter registry designed by the Brazilian Society of Cardiology, comprising 47 public and private hospital centers, representative of all the Brazilian regions. Those authors have assessed the occurrence of ischemic and hemorrhagic adverse events in 588 patients submitted to primary angioplasty via the femoral and radial accesses in 2010 and 2011. The radial technique was used in 30.3% of the cases, but was not associated with a reduction in the occurrence of death, reinfarction or stroke. Severe bleedings were reported in only 1.1% of the patients and did not statistically differ according to the arterial access used. Although the low incidence of cardiac and hemorrhagic complications can reflect the quality of the centers selected and the experience of the interventional cardiologists with both vascular access, as suggested by the researchers, the results of that registry indicate a dissociation between the available scientific evidence, which points to the significant benefits of the radial access in STEMI, and the actual use of that technique and its results in daily practice.

Radial access and the reduction in mortality and adverse cardiac events

Although the causal relationship remains controversial, several studies have reported that the radial access for primary angioplasty is associated with a reduction in mortality and in adverse cardiac events (Table 1). The largest clinical trial comparing the arterial accesses for percutaneous coronary intervention, the randomized and multicenter Radial Versus Femoral Access for Coronary Intervention (RIVAL) trial10, has selected individuals with acute coronary syndromes (ACS) with or without ST-segment elevation, to whom the invasive strategy had been indicated. Individuals with the following characteristics were excluded: cardiogenic shock or previous coronary artery bypass grafting (CABG) - which could make coronary angiography and the study of bypass grafts via the radial access difficult -, and peripheral arterial disease that could make the femoral approach unfeasible. Of the 7,021 patients randomized for femoral (n = 3,514) or radial (n = 3,507) access, 1,958 individuals (28%) were diagnosed with STEMI. In that specific subgroup, patients undergoing coronary angiography and angioplasty via radial access had lower rates of mortality (1.3% versus 3.2%, p = 0.006) and of the combined outcome of death, infarction and stroke (2.7 versus 4.6%, p = 0.031) at 30 days, as compared with individuals undergoing the procedure via femoral access. The beneficial results of the RIVAL trial in the subgroup of STEMI patients have been replicated in the Radial Versus Femoral Randomization Investigation in ST-Elevation Acute Coronary Syndrome (RIFLE-STEACS)11, a randomized clinical trial with 1,001 patients. Mortality at 30 days was significantly lower in patients undergoing angioplasty via radial access (5.2% versus 9.2%, p = 0.020). In addition, the subanalysis of the Harmonizing Outcomes with Revascularization and Stents in Acute Myocardial Infarction (HORIZONS-AMI) trial12 has revealed a significantly lower incidence of death and reinfarction at 30 days in individuals treated via the radial access (1.0% versus 4.3%; p = 0.02).

Mortality in different randomized trials of the radial and femoral arterial accesses
Trial RADIAL, n (%) FEMORAL, n (%) p
RIVAL10 (n = 1,958) 12/955 (1.3) 32/1.003 (3.2) 0.006
RIFLE-STEACS11 (n = 1,001) 26/500 (5.2) 46/501 (9.2) 0.020
HORIZONS-AMI12 (n = 3,334) 7/200 (3.5) 126/3.134 (4) 0.69
STEMI-RADIAL21 (n = 707) 8/348 (2.3) 11/359 (3.1) 0.64

Although those trials have been designed to neither specifically assess the occurrence of death as primary outcome nor to unravel the potential mechanisms associated with its reduction, the favorable impact on the incidence of bleedings has been assumed to be the major determinant of the lower mortality of patients treated via the radial access.

 Radial access and the reduction in bleeding

The implementation of more diversified and potent antithrombotic and antiplatelet regimens has determined a significant decrease in the rates of death, infarction and recurring ischemia of patients with ACS. The reduction in ischemic events is, however, opposed to the risk of hemorrhagic complications, whose presence and severity are currently recognized as important short- and long-term prognostic factors13,14. Several observational studies have shown the association between bleedings and the appearance of thrombotic cardiac events15,16. That evidence supports the adoption of a new paradigm in the ACS treatment: therapies or strategies that preserve the anti-ischemic efficacy and reduce the occurrence of bleeding cause an even greater reduction in the incidence of adverse cardiac events.

The complications related to femoral artery puncture account for a significant amount of hemorrhagic events occurring in patients with ACS. Because of its superficial location, hemorrhages in the radial access site are rare, rapidly noted and easily controlled. Thus, that access is one of the major tools of the interventional cardiologist to reduce bleedings (Table 2). Data from approximately 330 thousand patients with STEMI included in the North American National Cardiovascular Data Registry (NCDR)17 have shown a significant decrease in the bleeding rate with the radial access as compared with the femoral access (odds ratio, 0.62; 95% CI: 0.53-0.72; p <0.0001). In the RIFLE-STEACS trial, major bleedings after angioplasty were defined based on the Bleeding Academic Research Consortium (BARC)18 criterion greater than or equal to 2: patients randomized to the radial access have experienced a significant reduction in bleedings (7.8% versus 12.2%, p = 0.026), mainly at the puncture site11. In the HORIZONS-AMI trial, the incidence of major bleeding not related to CABG was 3.5% in patients undergoing primary angioplasty via radial access and 7.6% in those treated via the femoral access (p = 0.03)12. According to that study, even when drugs with a greater safety profile are used (bivalirudin), the radial access is beneficial. In addition and even consequent to the reduction in hemorrhagic complications, the radial access provides a lower rate of blood product transfusion: in the Mortality benefit Of Reduced Transfusion after PCI via the Arm or Leg (M.O.R.T.A.L) study19, patients with ACS undergoing transfusions had higher mortality at 30 days (odds ratio, 4.01; 95% CI: 3.08-5.22). The intervention via the radial access related to a 50% decrease in the need for blood products, and associated with lower mortality at 30 days (odds ratio, 0.71; 95% CI: 0.61-0.82; p < 0.001) and at 12 months (odds ratio, 0.83; 95% CI: 0.71-0.98; p < 0.001).

Major bleeding in different randomized trials of the radial and femoral arterial accesses
Trial RADIAL, n (%) FEMORAL, n (%) p
RIVAL10 (n = 1,958)* 19/995 (2.0) 41/1.003 (4.1) 0.009
RIFLE-STEACS11 (n = 1,001) 39/500 (7.8) 61/501 (12.2) 0.399
HORIZONS-AMI12 (n = 3,334) 7/200 (3.5) 237/3.134 (7.6) 0.03
STEMI-RADIAL21 (n = 707) 5/348 (1.4) 26/359 (7.2) 0.0001

In those clinical trials, the magnitude of the association between arterial approach and hemorrhagic complications has varied according to the proposed definition of bleeding. Thus, by using a criterion that elevates the qualification threshold of what is understood as major bleeding, the association can be masked. In the RIVAL trial, the major bleeding outcome was defined according to criteria specifically elaborated for that clinical trial, and did not differ between the radial and femoral accesses (0.8% versus 0.9%, p = 0.87). However, if ACUITY (Acute Catheterization and Urgent Intervention Triage strategy trial) bleeding definitions were used20, the bleeding rate was significantly higher in the femoral access group (4.5% versus 1.9%, p < 0.0001). In addition to the lack of event adjudication, the definition used by Andrade et al.9 can be one of the reasons for the low rate of severe bleeding observed in the ACCEPT registry; by considering severe hemorrhages only bleedings classified as BARC 3 or 5, events with potential clinical impact, such as the occurrence of a large hematoma at the femoral puncture site that required the interruption of antithrombotic and antiplatelet drugs, were excluded from the analysis.

 Myths and challenges of the radial access in STEMI

As shown in the ACCEPT registry, most Brazilian centers still use the femoral access in STEMI. Because of several reasons, many cardiologists can hesitate to indicate or incorporate the radial access in that scenario. Most limitations of that approach are not supported by scientific evidence. For patients with STEMI, vascular access for primary angioplasty should be obtained rapidly to minimize the duration of ischemia and to prevent myocardial necrosis from extending. In the NCDR registry, the use of the radial access was associated with a mild increase in the door to balloon time (78 versus 74 minutes), with no influence on in-hospital outcomes17. The ST-Elevation Myocardial Infarction treated by RADIAL or femoral approach (STEMI-RADIAL) multicenter randomized clinical trial21 has reported the low need for crossover of the femoral access (3.7%) and the use of a smaller volume of contrast medium for primary angioplasty with the radial approach (170 ± 71 versus 182 ± 60 mL; p = 0.01).

In addition, the option for one or the other approach has been shown to be related to changes in some technical aspects of primary angioplasty; although uncertain, such variations are likely to have a clinical impact. The BCIS-NICOR registry6 has shown that the use of manual thromboaspiration was frequent in patients treated via the radial access, and stenting was most frequently performed with no need for predilation (direct implantation): such strategies relate to lower rates of distal embolization and no-reflow. According to the Brazilian experience8, glycoprotein IIb-IIIa inhibitors have been more commonly used for the radial access. Those drugs begin to act rapidly and have a potent antiplatelet effect, being thus very useful under circumstances of large thrombotic load and slow-flow during the coronary intervention, in which the radial access provides greater safety for the use of glycoprotein IIb-IIIa inhibitors. In the European EUROTRANSFER registry22, patients treated with abciximab had a lower bleeding rate with the radial access (1.2% versus 9.4% as compared with the femoral access, p < 0.001).

Of all the challenges identified, the need for a higher learning curve to achieve proficiency with the radial procedures is the most important. In recent years, a significant increase has been reported in teaching and incorporation of that technique in training centers of interventional cardiologists23,24. The radial access requires greater dedication and commitment, which should never be a drawback when additional clinical benefits are aimed at for our patients.

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Stone GW White HD Ohman EM Bertrand ME Lincoff AM McLaurin BT et al Acute Catheterization and Urgent Intervention Triage strategY (ACUITY) Trial Investigators: Bivalirudin in patients with acute coronary syndromes undergoing percutaneous coronary intervention: a subgroup analysis from the Acute Catheterization and Urgent Intervention Triage strategy (ACUITY) trial Lancet 2007 369 9565 907 919 Bernat I, Horak D, Stasek J, Mates M, Pesek J, Ostadal P, et al. ST-Segment elevation myocardial infarction treated by radial or femoral approach in a multicenter randomized clinical trial. STEMI-RADIAL. J Am Coll Cardiol. 2014;63(10):964-72. Bernat I Horak D Stasek J Mates M Pesek J Ostadal P et al ST-Segment elevation myocardial infarction treated by radial or femoral approach in a multicenter randomized clinical trial. STEMI-RADIAL J Am Coll Cardiol 2014 63 10 964 972 Siudak Z, Zawislak B, Dziewierz A, Rakowski T, Jakala J, Bartus S, et al. 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Espírito Santo CV Melo PH Takimura CK Campos CA Horta PE Spadaro AG et al Tendências da utilização da via de acesso transradial em mais de uma década: a experiência do InCor Rev Bras Cardiol Invasiva 2014 22 2 120 124 Aguiar Filho GB, Siqueira DA, Chaves AJ, Coelho FM, Costa Jr JR, Veloso M, et al. Intervenção coronária percutânea pela via radial: incorporação da técnica e resultados de um centro de formação em cardiologia intervencionista. Rev Bras Cardiol Invasiva. 2012;20(4):367-72. Aguiar GB Filho Siqueira DA Chaves AJ Coelho FM Costa JR Jr Veloso M et al Intervenção coronária percutânea pela via radial: incorporação da técnica e resultados de um centro de formação em cardiologia intervencionista Rev Bras Cardiol Invasiva 2012 20 4 367 372 Angioplastia Primária no Registro ACCEPT: Por Que tem Sido Difícil Aceitar e Implementar a Via de Acesso Radial como Preferencial? Siqueira Dimytri Alexandre de Alvim 1 2 Brito Fabio Sandoli de Jr 3 Abizaid Alexandre A. C. 1 3 Instituto Dante Pazzanese de Cardiologia São Paulo SP Brasil Instituto Dante Pazzanese de Cardiologia, São Paulo, SP - Brasil. Hospital do Coração - ASS São Paulo SP Brasil Hospital do Coração - ASS, São Paulo, SP - Brasil. Hospital Israelita Albert Einstein São Paulo SP Brasil Hospital Israelita Albert Einstein, São Paulo, SP - Brasil. Correspondência: Dimytri A. Siqueira. Avenida Dr. Dante Pazzanese, 500, Seção de Cardiologia Invasiva, Prédio III, 1º andar − Vila Mariana − CEP: 04012-909 − São Paulo, SP, Brasil Angioplastia Artéria Radial Redução do Dano Fibrinolíticos Artéria Femoral / complicações

A obtenção do acesso arterial constitui a etapa inicial e fundamental dos procedimentos de intervenção coronária. Desde a sua primeira aplicação para a coronariografia1 e para a intervenção coronária percutânea2, tornou-se notório que a escolha pela via radial traduz-se em importantes benefícios clínicos, associando-se à redução de complicações vasculares e hemorrágicas do sítio de punção, à deambulação precoce e à maior satisfação dos pacientes quando comparada à via femoral. Recentemente, evidências advindas de grandes estudos randomizados e metanálises3,4 sugerem que, em pacientes com diagnóstico de infarto do miocárdio com elevação do segmento ST (IAMCSST), a angioplastia primária realizada pela via radial associa-se a significativa redução nas taxas de mortalidade e menor ocorrência de eventos cardíacos adversos. De fato, devido à consistência desses achados, diretrizes internacionais5 recomendam que a via radial seja a preferida nas situações de IAMCSST (classe IIa, nível de evidência B).

A incorporação da técnica radial, contudo, não tem sido abrangente, e sua penetração é distinta ao redor do mundo. Mais de 80% das intervenções coronárias realizadas na França são realizadas pela via radial. Dados do registro inglês BCIS-NICOR (British Cardiovascular Intervention Society - National Institute for Clinical Outcomes Research)6 apontam para um rápido crescimento na utilização dessa via de acesso nos últimos anos, elevando-se de 12,5% em 2006 para 49,5% em 2010. Nos Estados Unidos, por sua vez, apenas 16% das intervenções realizadas no período de 2007-2012 valeram-se do acesso radial7. Até então, os dados da realidade brasileira eram escassos. Segundo a Central Nacional de Intervenções Cardiovasculares (Cenic), no período de 2005-2008, a via radial havia sido utilizada em 12,6% dos casos, não sendo observado crescimento significativo na sua taxa de utilização nesse intervalo8. Em artigo bem-vindo e recentemente publicado, de Andrade e cols.9 nos fornecem um panorama mais atual acerca desse tópico. Utilizando dados de um grande registro nacional, idealizado pela Sociedade Brasileira de Cardiologia (SBC) e de natureza prospectiva e multicêntrica (47 centros hospitalares públicos e privados, representativos de todas as regiões federativas), os autores avaliaram a ocorrência de eventos cardiovasculares adversos isquêmicos e hemorrágicos em 588 pacientes submetidos a angioplastia primária pelas vias femoral e radial nos anos de 2010 e 2011. A técnica radial foi empregada em 30,3% dos casos, porém não esteve associada à redução na ocorrência de óbito, reinfarto ou acidente vascular cerebral. Sangramentos graves foram relatados em apenas 1,1% dos pacientes, sem diferença estatística conforme a via de acesso empregada. Embora a baixa incidência de complicações isquêmicas e hemorrágicas possa refletir a qualidade dos centros selecionados e a experiência dos cardiologistas intervencionistas com os acessos vasculares - conforme sugerido pelos próprios investigadores -, os resultados desse registro nos permitem aludir à aparente dissociação entre as evidências científicas disponíveis (que apontam os importantes benefícios da via radial no IAMCSST) e a real aplicação da técnica e os seus resultados na prática diária.

Acesso radial e redução de mortalidade e de eventos cardíacos adversos

Embora a relação causal ainda permaneça controversa, diversos estudos revelam que a escolha da via radial para a realização da angioplastia primária associa-se à redução de mortalidade e de eventos cardíacos adversos (Tabela 1). O maior estudo clínico comparativo entre as vias de acesso, o ensaio randomizado e multicêntrico RIVAL (Radial Versus Femoral Access for Coronary Intervention)10 selecionou indivíduos com síndromes coronárias agudas (SCA) com ou sem supradesnivelamento de ST, nos quais a estratégia invasiva estivesse indicada. Foram excluídos indivíduos com choque cardiogênico, revascularização miocárdica cirúrgica prévia - que poderia dificultar a realização de coronariografia e estudo de pontes pela via radial - e aqueles com doença arterial periférica que inviabilizasse o uso da via femoral. Dos 7.021 pacientes randomizados para acesso femoral (n = 3.514) ou radial (n = 3.507), 1.958 indivíduos (28%) possuíam o diagnóstico de IAMCSST. Nesse subgrupo específico, os pacientes que foram submetidos a coronariografia e angioplastia pela via radial apresentaram menores taxas de mortalidade (1,3 versus 3,2%, p = 0,006) e do desfecho composto por óbito, infarto e AVC (2,7 versus 4,6%, p = 0,031) aos 30 dias, quando comparados aos indivíduos submetidos ao procedimento pela femoral. Os resultados benéficos do estudo RIVAL no subgrupo de pacientes com IAMCSST foram replicados no ensaio clínico randomizado RIFLE-STEACS (Radial Versus Femoral Randomization Investigation in ST-Elevation Acute Coronary Syndrome)11, com 1.001 pacientes. A mortalidade aos 30 dias foi significativamente menor nos pacientes submetidos a angioplastia pela via radial (5,2% versus 9,2%, p = 0,020). Também representativa, a subanálise do estudo HORIZONS (Harmonizing Outcomes with Revascularization and Stents in Acute Myocardial Infarction)12 revelou que a incidência de óbito e reinfarto aos 30 dias foi reduzida de forma significativa nos indivíduos tratados pela via radial (1,0% versus 4,3%; p = 0,02).

Mortalidade em diferentes ensaios randomizados entre as vias de acesso radial e femoral
Estudo RADIAL, n (%) FEMORAL, n (%) p
RIVAL10 (n = 1.958) 12/955 (1,3) 32/1.003 (3,2) 0,006
RIFLE-STEACS11 (n = 1.001) 26/500 (5,2) 46/501 (9,2) 0,020
HORIZONS-AMI12 (n = 3.334) 7/200 (3,5) 126/3.134 (4) 0,69
STEMI-RADIAL21 (n = 707) 8/348 (2,3) 11/359 (3,1) 0,64

Embora nenhum desses estudos tenha sido desenhado especificamente para averiguar a ocorrência de óbito como desfecho primário (nem tampouco para desvendar o potencial mecanismo associado à sua redução), presume-se que o impacto favorável sobre a incidência de sangramentos seja o principal determinante para a menor mortalidade encontrada nos pacientes tratados pela via radial.

 Acesso radial e redução de sangramentos

A implementação de regimes antitrombóticos e antiplaquetários mais diversificados e potentes determina significativa diminuição nas taxas de óbito, infarto e isquemia recorrente em pacientes com SCA. A redução de eventos isquêmicos é, contudo, confrontada com o risco de complicações hemorrágicas, cuja presença e severidade são reconhecidas, atualmente, como importantes fatores prognósticos a curto e longo prazos13,14. Vários estudos observacionais demonstram a associação entre sangramentos e o surgimento de eventos cardíacos de natureza trombótica15,16. Tais evidências suportam a adoção de um novo paradigma no tratamento das SCA: terapias ou estratégias que preservem a eficácia anti-isquêmica e reduzam a ocorrência de sangramentos determinam redução ainda mais pronunciada de eventos cardíacos adversos.

As complicações relacionadas à punção da artéria femoral são responsáveis por significativa parcela dos eventos hemorrágicos ocorridos em pacientes com SCA. Em razão de sua localização superficial, as hemorragias no sítio radial são raras, rapidamente notadas e facilmente controladas. Dessa forma, a opção por essa via constitui uma das principais ferramentas do cardiologista intervencionista para a redução de sangramentos (Tabela 2). Dados de cerca de 330 mil pacientes com IAMCSST incluídos no registro americano NCDR (National Cardiovascular Data Registry)17 apontam para expressiva diminuição nas taxas de sangramento com a técnica radial, quando comparados à via femoral (odds ratio 0,62; IC 95% 0,53-0,72, p < 0,0001). No estudo RIFLE-STEACS, os sangramentos maiores ocorridos pós-angioplastia foram definidos por critério BARC (Bleeding Academic Research Consortium)18 maior ou igual a 2: pacientes randomizados para a via radial experimentaram significativa redução de sangramentos (7,8% versus 12,2%, p = 0,026), principalmente observados no sítio de punção11. No estudo HORIZONS-AMI, a incidência de sangramento maior não relacionado a cirurgia de revascularização foi de 3,5% nos pacientes submetidos a angioplastia primária pela via radial e de 7,6% naqueles tratados pela via femoral (p = 0,03)12; depreende-se a partir desse estudo, portanto, que, mesmo em situações nas quais os fármacos com maior perfil de segurança são empregados (no caso, a bivalirrudina), a técnica radial promove benefícios. Vantagem consequente e aditiva à redução de complicações hemorrágicas, a via radial proporciona ainda menor taxa de transfusões de hemoderivados: no registro M.O.R.T.A.L (Mortality benefit Of Reduced Transfusion after PCI via the Arm or Leg)19, pacientes com SCA submetidos a transfusões apresentaram maior mortalidade aos 30 dias (odds-ratio, 4,01; IC 95% 3,08-5,22). A intervenção pela via radial esteve relacionada ao decréscimo de 50% na necessidade de hemoderivados, associando-se a menor mortalidade aos 30 dias (odds-ratio, 0,71; IC 95% 0,61-0,82; p < 0,001) e aos 12 meses (odds-ratio, 0,83; IC 95%, 0,71-0,98; p <0,001).

Sangramento maior em diferentes ensaios randomizados entre as vias de acesso radial e femoral
Estudo RADIAL, n (%) FEMORAL, n (%) p
RIVAL10 (n = 1.958)* 19/995 (2,0) 41/1.003 (4,1) 0,009
RIFLE-STEACS11 (n = 1.001) 39/500 (7,8) 61/501 (12,2) 0,399
HORIZONS-AMI12 (n = 3.334) 7/200 (3,5) 237/3.134 (7,6) 0,03
STEMI-RADIAL21 (n = 707) 5/348 (1,4) 26/359 (7,2) 0,0001

Nesses estudos clínicos, a magnitude da associação entre a via de acesso e as complicações hemorrágicas varia de acordo com a definição proposta de sangramento. Assim, ao utilizar critério que eleva o limiar de qualificação do que se entende como sangramento maior, pode-se mascarar a associação. No estudo RIVAL, o desfecho sangramento maior foi definido por critérios elaborados especificamente para esse ensaio clínico, e não diferiu entre os grupos radial e femoral (0,8 versus 0,9%, p = 0,87). Quando analisados de acordo com a classificação ACUITY20, porém, a taxa de sangramento maior foi significativamente mais pronunciada no grupo femoral (4,5 versus 1,9%, p < 0,0001). Associadamente à não adjudicação dos eventos, a definição aplicada por Andrade e cols.9 pode ser uma das razões para a baixa taxa de sangramentos graves observada no registro ACCEPT; ao caracterizar como hemorragias graves apenas os sangramentos do tipo BARC 3 ou 5, excluem-se da análise eventos com potencial impacto clínico, como por exemplo a ocorrência de grande hematoma em sítio de punção femoral que requereu a suspensão de fármacos antitrombínicos e antiplaquetários.

 Mitos e desafios da via radial no IAMCSST

Conforme o registro ACCEPT nos revela, a maioria dos centros nacionais ainda emprega o acesso femoral no IAMCSST. Por uma série de motivos, muitos cardiologistas podem hesitar em indicar ou incorporar a técnica radial nesse cenário. Das limitações aventadas dessa via de acesso, a maioria não é embasada por evidências científicas. Diante de pacientes com IAMCSST, o acesso vascular para a angioplastia primária deve ser obtido rapidamente para que se minimize o tempo de isquemia e se previna a extensão da necrose miocárdica. No registro NCDR, o uso da via radial esteve associado a discreto aumento no tempo porta-balão (78 versus 74 minutos), sem influência nos desfechos intra-hospitalares17. Os resultados do ensaio clínico randomizado STEMI-RADIAL (ST Elevation Myocardial Infarction treated by RADIAL or femoral approach)21 revelam, por sua vez, baixa necessidade de crossover para a via femoral (3,7%) e utilização de menor volume de contraste para a angioplastia primária com a via radial (170 ± 71 versus 182 ± 60 ml; p = 0,01).

Tem sido demonstrado, também, que a opção por uma ou outra via de acesso vincula-se a mudanças em alguns aspectos técnicos da angioplastia primária; embora incerto, é possível que tais variações exerçam impacto clínico. No registro BCIS-NICOR6, observou-se que o uso da tromboaspiração manual foi mais frequente em pacientes tratados pela via radial, e o implante de stents foi realizado na maioria das vezes sem necessidade de pré-dilatação (técnica denominada implante direto): tais estratégias relacionam-se com menor ocorrência de embolização distal e no-reflow. Na experiência nacional8, os inibidores de glicoproteína IIb-IIIa foram mais comumente empregados no grupo radial. Por apresentarem rápido início de ação e potente efeito antiplaquetário, esses fármacos são muito úteis em circunstâncias de grande carga trombótica e slow-flow durante a intervenção coronária. Nessas circunstâncias, o acesso radial promove maior segurança na utilização de inibidores da glicoproteína IIb-IIIa. No registro europeu EUROTRANSFER22, pacientes tratados com abciximab evoluíram com menor taxa de sangramentos com o acesso radial (1,2% versus 9,4% na comparação com a via femoral, p <0,001).

A necessidade de maior curva de aprendizado para se alcançar a proficiência nos procedimentos radiais é, dentre todos os desafios percebidos, o mais importante. Nos últimos anos, felizmente, tem sido reportado apreciável aumento no ensino e na incorporação da técnica em centros de formação de futuros cardiologistas intervencionistas23,24. De certo, a via radial exige maior dedicação e comprometimento, o que nunca deve ser empecilho quando se almeja oferecer benefícios clínicos adicionais aos nossos pacientes.