Antithrombotic agents in the prevention of ischemic stroke.

The role of antithrombotic drugs in the prevention of cerebral infarction is well established: antiplatelet drugs, at present mostly aspirin, clopidogrel, and aspirin + extended-release dipyridamole, decrease the relative risk of cerebral infarction, myocardial infarction and vascular death by 25% in patients with a cerebral ischemic event due to large- or small-artery disease of the brain. In primary prevention, aspirin decreases stroke risk by 19% in women but not in men. In patients with nonvalvular atrial fibrillation (NVAF), aspirin decreases the risk of ischemic stroke by 20%. Oral anticoagulants, at present only vitamin K antagonists, decrease the risk of cerebral infarction in NVAF by 65-70% compared with placebo and by 40% compared with aspirin. Oral anticoagulants are as effective as aspirin in arterial diseases of the brain, but induce more hemorrhages and are less convenient. Studies are ongoing with new antiplatelet drugs and new anticoagulants which might modify the present state of the art. Studies are also needed to evaluate the benefit/risk ratio of the combination of anticoagulants and antiplatelet drugs in aged subjects with both NVAF and arterial diseases of the brain.