Antiplatelet drugs in secondary prevention of stroke

More than 50 randomized controlled trials have been conducted to determine the value of antiplatelet agents, most notably aspirin, for stroke prevention.1 Interpretation and comparison of trial results have been hampered by the studies' widely disparate patient populations, inclusion criteria, end points, and treatment protocols. Despite these difficulties, the efficacy of antiplatelet therapy in the prevention of ischemic cerebrovascular events is well established. By the late 1980s, many studies, including the French study known as AICLA(Accidents Ischemiques Cérébraux Liés à l'Athérosclérose), the first European Stroke Prevention Study(ESPS-1), and the first meta-analysis by the Antiplatelet Trialists' Collaboration, had demonstrated that antiplatelet therapy can significantly reduce the risk for fatal and nonfatal stroke among patients with a prior history of stroke or transient ischemic attack (TIA).2-4 In 1994, a second meta-analysis by the Antiplatelet Trialists' Collaboration concluded that antiplatelet therapy prevents between 20 and 30 nonfatal strokes for every 1,000 high-risk patients treated.5 Although the evidence of antiplatelet therapy's utility for secondary stroke prevention is compelling, questions have remained concerning the specifics of treatment. From a clinical standpoint, a primary question is whether the observed benefit of antiplatelet therapy justifies routine treatment of all eligible patients. If we assume that the answer is yes, other questions naturally follow: