Antithrombotic therapy after myocardial infarction in patients with atrial fibrillation undergoing percutaneous coronary intervention

Aims: Optimal antithrombotic therapy after percutaneous coronary intervention (PCI) in patients with myocardial infarction (MI) and atrial fibrillation is uncertain. In this study, we compared antithrombotic regimes with regard to a composite cardiovascular outcome of all-cause mortality, MI or ischaemic stroke, and major bleeds. Methods and results: Patients between October 2005 and December 2012 were identified in Swedish registries, n = 7116. Landmark 0-90 and 91-365 days of outcome were evaluated with Cox-regressions, with dual antiplatelet therapy as reference. At discharge, 16.2% received triple therapy (aspirin, clopidogrel, and warfarin), 1.9% aspirin plus warfarin, 7.3% clopidogrel plus warfarin, and 60.8% dual antiplatelets. For cardiovascular outcome, adjusted hazard ratio with 95% confidence interval (HR) for triple therapy was 0.86 (0.70-1.07) for 0-90 days and 0.78 (0.58-1.05) for 91-365 days. A HR of 2.16 (1.48-3.13) and 1.61 (0.98-2.66) during 0-90 and 91-365 days, respectively, was observed for major bleeds. For aspirin plus warfarin, HR 0.82 (0.54-1.26) and 0.62 (0.48-0.79) was observed for cardiovascular outcome and 1.30 (0.60-2.85) and 1.01 (0.63-1.62) for major bleeds during 0-90 and 91-365 days, respectively. For clopidogrel plus warfarin, HR of 0.90 (0.68-1.19) and 0.68 (0.49-0.95) was observed for cardiovascular outcome and 1.28 (0.71-2.32) and 1.08 (0.57-2.04) for major bleeds during 0-90 and 91-365 days, respectively. Conclusion: Compared to dual antiplatelets, aspirin or clopidogrel plus warfarin therapy was associated with similar 0-90 days and lower 91-365 days of risk of the cardiovascular outcome, without higher risk of major bleeds. Triple therapy was associated with non-significant lower risk of cardiovascular outcome and higher risk of major bleeds.