MY APPROACH to the use of aspirin

Abstract

Multiple randomized clinical trials have established that aspirin reduces the incidence of stroke andmyocardial infarction in patients with established cardiovascular disease. The antithrombotic effect of aspirin is due to inhibition of platelet aggregation by blocking the production of thromboxane A2. Long-term aspirin is recommended in all patients with known cardiovascular disease who do not have relative contraindications, such as a history of gastrointestinal (GI) bleeding or peptic ulcer. The recommended dose in the United States is 81mg/day. The indications for aspirin in primary prevention—that is in patients with risk factors for cardiovascular disease who do not have a history of coronary heart disease or stroke—are not as clear. The Physicians’ Health study in 1989 randomized 22,071 physicians without a history of coronary artery disease to 325 mg aspirin every other day or placebo. After 5 years of therapy, they reported a very significant (P o .00001) reduction in myocardial infarction in those in the aspirin arm. However, multiple primary prevention trials since have been negative. As a result, many have concluded that aspirin is not indicated for primary prevention because the potential benefit is exceeded by the risk for GI bleeding. All of the primary prevention trials have used doses of aspirin of 100 mg or less