Direct Oral Anticoagulation Versus Warfarin in Patients with Atrial Fibrillation and Bioprosthetic Heart Valves: a Retrospective, Real-World Cohort Study.

Abstract

In this retrospective cohort study of consecutive patients with atrial fibrillation and surgical or transcatheter bioprosthetic valve, we compared the efficacy and safety of direct oral anticoagulants withwarfarin. Using linked health administrative databases housed at the Institute for Clinical Evaluative Sciences, we identified consecutive patients in Ontario (Canada) 65years of age or older with AF who underwent bioprosthetic valve replacement between 1 April 2012 and 31 March 2017. We created a time-varying Cox model to examine the relationship between the type of anticoagulant and time to thrombotic or bleeding events after adjustment for baseline risk of thrombosis using the CHA2DS2-VASc score and risk ofbleeding using the HAS-BLED scores. We conductedprespecified subgroup analyses according to whether valve implantation was surgical or transcatheter. We identified 2245 eligible patients. The mean age was 79years, 41% were female, and 39% had transcatheter aortic valve replacement. Risk of death or thrombosis was not differentbetween direct oral anticoagulants and warfarin after adjustment for CHA2DS2-VASc score (hazard ratio [HR] 1.02, 95% confidence interval [CI], 0.83-1.25). Risk of death or bleeding was not differentbetween direct oral anticoagulants and warfarin after adjustment for HAS-BLED score (HR 0.89, 95% CI 0.75-1.07). Subgroup analyses of surgical or transcatheter valves were consistent with overall results. In a real-world population of patients with atrial fibrillation and bioprosthetic valve replacement, we foundno difference between direct oral anticoagulants and warfarin with regard to the risk of thrombosis or bleeding.