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Reference: Lancet 2013 Mar 30;381(9872):1107, (level 2 [mid-level] evidence)
Addition of antiplatelet therapy is recommended for prevention of stent thrombosis in patients taking long-term oral anticoagulants who are having percutaneous coronary intervention (PCI) (Eur Heart J 2010 Oct;31(20):2501, Circulation 2006 Jan 3;113(1):156). However, the combination of antiplatelet and anticoagulant therapies may increase bleeding risks, and the optimal antiplatelet regimen for these patients is unclear. A recent unblinded randomized trial compared the efficacy of clopidogrel alone vs. dual antiplatelet therapy with clopidogrel plus aspirin in 573 patients having PCI.
Patients (mean age 70 years) who were taking anticoagulants and having PCI were randomized to clopidogrel 75 mg/day vs. clopidogrel 75 mg/day plus aspirin 80-100 mg/day (dual therapy). Most patients were taking long-term anticoagulants for atrial fibrillation (69%). Other indications included mechanical valves, peripheral arterial disease, pulmonary embolism, and reduced ejection fraction. All patients started clopidogrel 5 days prior to PCI, with a loading dose of 300 mg at least 24 hours (or 600 mg at least 4 hours) before surgery. The allocated antiplatelet therapy was continued for 1 month to 1 year at the discretion of the treating physician in patients with stable coronary disease who received bare metal stents. Clopidogrel was continued for 1 year in patients with acute coronary syndrome or who received drug-eluting stents.
At 1-year follow-up, there were no significant differences in cardiovascular outcomes, including rates of myocardial infarction, stroke, stent thrombosis, and target vessel revascularization. Clopidogrel monotherapy was associated with reductions in bleeding events (19.4% vs. 44.4%, p < 0.0001, NNT 4), blood transfusions (3.9% vs. 9.5%, p = 0.01, NNT 18) and all-cause mortality (2.5% vs. 6.3%, p = 0.027, NNT 27). Cardiovascular mortality was 1.1% with clopidogrel monotherapy and 2.5% with dual antiplatelet therapy (not significant).
For more information, see the Antiplatelet and anticoagulant drugs for elective percutaneous coronary intervention (PCI) topic in DynaMed.