Antithrombotic therapy for cerebrovascular disorders.

Ischemic stroke is a syndrome, and the optimal use of an¬ tithrombotic therapies in patients at risk for ischemic stroke is guided by the specific pathogenesis (Figs 1 and 2). Patients with increased risk for ischemic stroke can be identified (Table 1). Atherosclerosis of arteries, large and small, supplying the brain is the most common cause of is¬ chemic stroke in North America and Europe. Atherosclero¬ sis of the proximal aorta is another source of atherogenic emboli recently detectable by transesophageal echocardi¬ ography. Microatheroma and other occlusive disease of the small penetrating brain arteries are the most frequent causes of small, subcortical "lacunar" infarcts. About 20% of ischemic strokes are due to cardiogenic embolism. A variety of other arterial occlusive disorders may be the primary cause or variably contribute to stroke pathogenesis. Overall, about 30% ofischemic strokes remain "cryptogenic" despite