Ischemic stroke exacts a heavy toll in death and disability worldwide. In the United States, where it is the third leading cause of death and the leading cause of serious long-term disability, approximately 750,000 strokes occur annually, with an annual mortality rate exceeding 150,000.1–4 In June 1996, the Food and Drug Administration (FDA) approved tissue plasminogen activator (t-PA) as a safe and effective treatment for stroke if it is given within three hours after the onset of symptoms of stroke.5 Subsequently, results of large clinical trials testing the efficacy of antiplatelet, antithrombotic, and neuroprotective treatments appeared. More recently, intraarterial . . .