Antiplatelet therapy: new foundations for optimal treatment decisions

Individuals who experience a stroke or a transient ischemic attack require long-term treatment to prevent a subsequent stroke. According to the current guidelines, patients with a first cerebrovascular event due to cardioembolism should be treated with oral anticoagulants, barring any contraindications. Individuals with ischemic cerebral events due to atherothrombosis should typically receive antiplatelet agents. Aspirin is the best-studied antiplatelet agent and has been used in stroke prevention for many years. Trials evaluating aspirin have, over time, enrolled more patients and tested lower aspirin doses. No individual trial conducted in cerebrovascular patients has established the optimal aspirin dose for prevention of vascular events, but meta-analyses of trials at different dose ranges and the two single trials that directly compared different doses strongly suggest that the benefit of aspirin is independent of dose in this patient population. Lower doses (50-325 mg daily) are now recommended because of their more favorable side-effect profiles. Because its value is established, aspirin has been used as a control to evaluate other antiplatelet agents. On the basis of large clinical trials versus aspirin, three other antiplatelet agents (ticlopidine, clopidogrel, and the combination of aspirin plus extended-release dipyridamole) have all been shown to be effective for stroke prevention. Physician opinions regarding the efficacy of these agents in indirect comparisons and the differences in their safety profiles, availability, and cost will influence the choice of agent for the individual patient.