Direct oral anticoagulation versus warfarin in patients with atrial fibrillation and bioprosthetic heart valves: a retrospective, real-world cohort study

Objective — 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 with warfarin.

Methods — Using linked health administrative databases housed at the Institute for Clinical Evaluative Sciences, we identified consecutive patients in Ontario (Canada) 65 years 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 of bleeding using the HAS-BLED scores. We conducted prespecified subgroup analyses according to whether valve implantation was surgical or transcatheter.

Results — We identified 2245 eligible patients. The mean age was 79 years, 41% were female, and 39% had transcatheter aortic valve replacement. Risk of death or thrombosis was not different between 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 different between 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.

Conclusions — In a real-world population of patients with atrial fibrillation and bioprosthetic valve replacement, we found no difference between direct oral anticoagulants and warfarin with regard to the risk of thrombosis or bleeding.