Papel do ácido acetilsalicílico na prevenção primária cardiovascular. Revisão baseada na evidência

Abstract

Introduction: The benefits of acetylsalicylic acid (ASA) in secondary prevention of cardiovascular (CV) diseases clearly outweigh its harms. However, its role in primary prevention remains controversial. The aim of this study is to undertake an evidence-based review of to whom CV primary prevention (PP) must be done and with which dosage. Methodology: A systematic literature search was conducted in MEDLINE, Cochrane Libary, Bandolier, Medscape, Tripdatabase, DARE, EBM Resources and US Preventive Services Task Force databases, selecting articles published from January, 1985 until January, 2006. It entailed nine randomized clinical trials (RCT), eight systematic reviews (SR), four evidence-based reviews (EBR), four evidence-based guidelines (EBG). Concerning primary prevention in diabetic patients, two RCT, one SR, two RBE and three EBG were included; about PP in hypertensive patients, the study included one RCT, two SR and one EBG. Results: The analysis of the combined data of 6 RCT (n=95.456) revealed a significant 32% reduction in the incidence of myocardial infarction (MI) and a non-significant reduction in the incidence of cerebral vascular diseases (CVD) among those taking ASA. The data analysis by gender revealed different benefits for each sub-group. In men, there was a significant 12% reduction of the risk of CV events and a significant 32% reduction in the incidence of MI. In women, significant 12% and 19% reductions of CV events and CVD, respectively, were obtained. The diabetic patients and hypertense patients were analysed separately. As ASA therapy side effects, a significant increase in gastrointestinal bleeding and a non-significant reduction of hemorragic CVD were found. Discussion: There is good evidence that ASA reduces the incidence of MI in adults with an increased CV risk and that ASA increases the incidence of gastrointestinal bleeding. A fair evidence of the increase of bleeding CVD was obtained. It is important to take into account the tensional control when considering PP with ASA. Several societies guidelines’, with the respective recommendation levels, are discussed and compared, namely about the CV risk level above which primary prevention with ASA is recommended. Conclusions: The benefits of ASA seem directly related with the CV risk increase with the increase of the risk of CV events. Therefore, the latter must be estimated when deciding about AAS use. Effective CV primary prevention can be achieved with as few as 75-150mg/day. More RCT studies are needed, especiallyin diabetic patients.