Aspirin for Secondary Prevention of Atherosclerosis

Decades of recommendations to give aspirin for primary prevention of cardiovascular events, based on overoptimistic interpretation of inconclusive data, were recently overturned after a randomized clinical trial with approximately 100 000 person-years of follow-up found that aspirin increased all-cause mortality; several other primary prevention trials of aspirin also failed to show meaningful reductions in cardiovascular events. Furthermore, a trial of 17 444 patients undergoing orthopedic surgery suggested increases in myocardial infarction (MI) with aspirin 160 mg per day. Many people randomized in primary prevention trials undoubtedly had undiagnosed atherosclerotic cardiovascular disease (ASCVD). Now that recommendations for prophylactic use of aspirin for primary prevention have been largely reversed, the stage is set to reconsider the strength of evidence for giving aspirin for secondary prevention.