Several antiplatelet agents with different mechanisms of action are currently available for secondary prevention of ischemic stroke. When used as a single agent, the efficacy of antiplatelet therapy is modest. Aspirin is the best-studied and most widely used antiplatelet agent for stroke prevention; however, it provides only an approximately 15% relative risk reduction for secondary prevention of stroke or other major vascular events. 1 Combining 2 antiplatelet agents with different mechanisms of action was demonstrated to provide a substantial increase in efficacy in the ESPS II study. 2 In this trial, the relative risk reduction for secondary stroke prevention was 37% with use of a combination of extended-release dipyridamole and aspirin. Importantly, the risk of major bleeding attributable to the combination therapy was no greater than that seen with aspirin alone.

Clopidogrel was shown to be a safe and efficacious medication for secondary prevention of vascular events in the CAPRIE study. 3 In this trial, the benefit of clopidogrel over aspirin for the prevention of vascular events was a relative risk reduction of 8.7%. In addition, there was less major bleeding in the clopidogrel group, yielding a relative net benefit of about 10%. It has been assumed by many physicians that the combination of clopidogrel with aspirin may be substantially more effective than either agent alone. In fact, many patients with cerebrovascular disease are currently treated with this combination despite the absence of any substantial safety or efficacy data regarding the use of this combination in stroke or transient ischemic attack (TIA) patients. Recently, the results of the Clopidogrel in Unstable Angina to Prevent Recurrent Events (CURE) trial were published. 4 This study assessed the safety and efficacy of the combination of clopidogrel and aspirin in patients with acute coronary syndromes without ST-segment elevation. Can the CURE results be extrapolated to cerebrovascular patients?