Aspirin for Primary Prevention of Cardiovascular Disease: A Contemporary Review

Aspirin has been fundamental in secondary prevention of cardiovascular disease (CVD) due to its antithrombotic effect. Its use in primary prevention, that is, preventing first-time cardiovascular events in persons without known CVD, has been controversial. Early trials, which were done in the late 20th century, showed moderate myocardial infarction reductions with aspirin, but they also showed an increased risk of bleeding. Over the past 10 years, several large randomized controlled trials (including Aspirin to Reduce Risk of Initial Vascular Events, A Study of Cardiovascular Events in Diabetes, and Aspirin in Reducing Events in the Elderly) have revisited this problem in diverse populations, which yielded mixed results that generally question the net benefit of routine aspirin use in low- to moderate-risk individuals. These findings brought some major guideline updates. Recent American College of Cardiology/American Heart Association (ACC/AHA) guidelines restrict aspirin to a few groups who are at a higher risk and advise against the routine use of aspirin in the rest of the population, while European Society of Cardiology guidelines generally discourage aspirin usage in primary prevention; its use is limited to specific, very high-risk settings. This article provides us with an overall summary of the evidence for aspirin primary prevention of CVD, taking into account prominent trials, the balance between benefits (eg, reduction in myocardial infarction) and harms (eg, bleeding), evolving clinical guidelines, and practical considerations of risk stratification and patient selection. Our work tried to highlight the manner in which aspirin's use in primary prevention in current practice is narrowly focused and should be individualized by careful consideration of risk-benefit and shared decision-making.