Antiplatelet agents for secondary prevention of stroke.

Patients with recent ischemic stroke or transient ischemic attack (TIA) face a high risk of recurrent stroke as well as an increased risk of myocardial infarction and sudden cardiac death. In the absence of a clearly established indication for long-term anticoagulation, such as atrial fibrillation, antiplatelet agents are the antithrombotic drugs of choice for preventing recurrent vascular events. For many years, aspirin (ASA) has been the first-line therapy for patients at high risk of vascular ischemic events. Two large clinical trials have established the superiority of the combination of ASA and extended-release dipyridamole (ASA/ERDP) over ASA alone in patients with recent noncardioembolic ischemic stroke or TIA. Clopidogrel, another antiplatelet agent, is a reasonable alternative to ASA, but its superiority to ASA in patients with a history of stroke has not been as clearly established. The combination of ASA and clopidogrel, which is effective in patients with acute coronary syndrome, has not been shown to be either effective or safe, compared with either agent alone, in stroke patients, although there may be some benefit to this combination in patients with acute TIA. The results from a large randomized trial comparing ASA/ERDP with clopidogrel, anticipated soon, will further assist clinicians in choosing among available antiplatelet agents.