Randomized clinical trial of the antiplatelet effects of aspirin-clopidogrel combination versus aspirin alone after lower limb angioplasty

BACKGROUND: There is a high risk of reocclusion after successful lower limb angioplasty. Platelets play a central role in this process. The aim of this study was to investigate the antiplatelet effect of a combination of aspirin and clopidogrel compared with aspirin alone in patients with claudication undergoing endovascular revascularization. METHODS: This was a double-blind randomized placebo-controlled trial. Some 132 patients were randomized to clopidogrel and aspirin or placebo and aspirin, with a loading dose 12 h before endovascular intervention. Flow cytometric measurements of platelet fibrinogen binding and P-selectin expression were taken as measures of platelet function at baseline, 12 h after the loading dose, and 1 h, 24 h and 30 days after intervention. RESULTS: Within 12 h of the loading dose, platelet activation in the clopidogrel group had decreased (P-selectin by 27.3 per cent, P = 0.017; fibrinogen binding by 34.7 per cent, P = 0.024; stimulated fibrinogen binding by 49.2 per cent, P < 0.001). No change was observed in the placebo group. Platelet function in the clopidogrel group was significantly suppressed compared with baseline at 1 h, 24 h and 30 days after endovascular intervention (stimulated fibrinogen binding by 53.9, 51.7 and 57.2 per cent respectively; all P < 0.001). CONCLUSION: A combination of clopidogrel and aspirin inhibited platelet function more than aspirin alone in patients with claudication before and after angioplasty.