Key Points Primary Prevention
ÎBased on meta-analyses including 95,000 individuals, aspirin use in patients at low risk over a 10-year period would be associated with six fewer myocardial infarctions (MIs) and four more major bleeding events per 1,000 treated, with little or no effect on nonfatal stroke.
ÎFor moderate- to high-risk patients, aspirin would reduce nonfatal MIs (19 fewer/1,000 treated and 31 fewer/1,000 treated, respectively) and increase major bleeding (16 more/1,000 treated and 22 more/1,000 treated, respectively), with a similar impact on total mortality as in the low-risk group (six fewer total deaths).
Secondary Prevention
ÎRecommendations for therapy following acute coronary syndrome (ACS) will apply to the postdischarge period and extend to 1 year. Thereafter, patients will be considered to have established coronary artery disease (CAD), although the higher-risk period following ACS may end before 1 year.
ÎAntiplatelet agents exert similar effects on vascular events in patients with a history of MI and in patients with a history of stable angina and CAD.
Treatment Established Coronary Artery Disease
ÎFor persons aged 50 years or older without symptomatic cardiovascular disease:
• The American College of Chest Physicians (ACCP) suggests low-dose aspirin 75 to 100 mg daily over no aspirin therapy (2-B). Remark: Aspirin slightly reduces total mortality regardless of cardiovascular risk profile if taken over 10 years. In people at moderate to high risk of cardiovascular events, the reduction in MI is closely balanced with an increase in major bleeds. Whatever their risk status, people who are averse to taking medication over a prolonged time period for very small benefits will be disinclined to use aspirin for primary prophylaxis. Individuals who value preventing an MI substantially higher than avoiding a gastrointestinal (GI) bleed, if they are in the moderate or high cardiovascular risk group, will be more likely to choose aspirin.
ÎFor patients with established CAD (including patients after the first year post-ACS and/or with prior coronary artery bypass graft [CABG] surgery):
• The ACCP recommends long-term single antiplatelet therapy with aspirin 75 to 100 mg daily or clopidogrel 75 mg daily over no antiplatelet therapy (1-A).
• The ACCP suggests single over dual antiplatelet therapy with aspirin plus clopidogrel (2-B).
