European Stroke Prevention Study. 2. Dipyridamole and acetylsalicylic acid in the secondary prevention of stroke.

Abstract In 1988, we undertook a randomized, placebo-controlled, double-blind trial to investigate the safety and efficacy of low-dose acetylsalicylic acid (ASA), modified-release dipyridamole, and the two agents in combination for secondary prevention of ischemic stroke. Patients with prior stroke or transient ischemic attack (TIA) were randomized to treatment with ASA alone (50 mg daily), modified-release dipyridamole alone (400 mg daily), the two agents in a combined formulation, or placebo. Primary endpoints were stroke, death, and stroke or death together. TIA and other vascular events were secondary endpoints. Patients were followed on treatment for two years. Data from 6,602 patients were analysed. Factorial analysis demonstrated a highly significant effect for ASA and for dipyridamole in reducing the risk of stroke ( p ≤ 0.001) and stroke or death combined ( p p = 0.013); 16% with dipyridamole alone ( p = 0.039); and 37% with combination therapy ( p p = 0.016); 15% with dipyridamole alone ( p = 0.015); and 24% with the combination ( p p p p