The role of warfarin and aspirin in secondary prevention of stroke.

Antithrombotic therapy plays a central role in secondary prevention after ischemic stroke and transient ischemic attack. The choice among warfarin, aspirin, and other antiplatelet agents, however, depends on the cause of stroke and other individual patient characteristics. The use of warfarin anticoagulation in patients with atrial fibrillation and ischemic stroke has demonstrated robust reductions in risk of recurrent events, comparable with those achieved in primary prevention. Warfarin may also be recommended for patients with other high-risk cardioembolic sources of stroke. The role of warfarin in noncardioembolic ischemic stroke is more controversial. The Warfarin Aspirin Recurrent Stroke Study found no evidence of superiority of warfarin over aspirin in stroke patients overall, nor in any major stroke subtype, including those patients with patent foramen ovale. In post-hoc analyses, there was some evidence of benefit with warfarin in patients with cryptogenic stroke without hypertension. Risks of major bleeding did not differ significantly between warfarin and aspirin groups. For most patients with noncardioembolic strokes, therefore, antiplatelet therapy is the preferred option, although clinician experience still dictates practice in individual situations. Newer antiplatelet agents, and the combination of novel agents with aspirin, are also finding a role in stroke prevention as clinical trial data become available.