[Antiaggregation: aspirin]

Abstract

Many randomized trials have shown aspirin as an effective antiplatelet drug for the secondary prevention of cardiovascular events. The NNT (number needed to treat) to prevent 1 vascular event is about 25. The NNH (number needed to harm) inducing one cerebral bleeding is about 1'000, to provoke one severe extracerebral bleeding about 100-200. The primary prevention can be recommended only for high risk patients for cardiovascular events (annual risk of 1-1.5% or more), calculated on the basis of the Framingham data, the Sheffield tables or in analysis of U.S. Preventive Services Task Force. The mechanisms of action, interactions and the "aspirin-resistance" are briefly discussed.