Aspirin to prevent heart attack or stroke.

Each year in the United Kingdom about 250,000 people die from acute myocardial infarction, other ischaemic heart disease or stroke. Many will already have evidence of established vascular disease that predisposes to such an event--such as angina, peripheral vascular disease, atrial fibrillation, transient ischaemic attacks or a previous myocardial infarction or stroke. Others will have risk factors such as hypertension, diabetes mellitus or hyperlipidaemia, but the stroke or heart attack is the first evidence of established vascular disease. Aspirin was first discovered to have antiplatelet properties 30 years ago and since then many randomised clinical trials have sought to determine whether it (or other antiplatelet agents) can protect patients from heart attack or stroke. In this article we review the evidence and update our earlier conclusions on stroke, myocardial infarction, and unstable angina, arguing that aspirin should be widely used to reduce cardiovascular morbidity and mortality in certain high-risk patients.