Comparison of the Efficacy and Safety of Direct Oral Anticoagulants and Warfarin After Bioprosthetic Valve Replacements.

Abstract

Current guidelines recommend anticoagulation with a vitamin K antagonist (warfarin) after a bioprosthetic valve replacement. There is minimal literature evaluating direct oral anticoagulants (DOACs) in patients who have just received a bioprosthetic aortic valve replacement (AVR) or mitral valve replacement (MVR). The purpose of this study was to investigate any differences in efficacy and safety for patients taking a DOAC, compared with warfarin, after a bioprosthetic AVR or MVR. A retrospective cohort study was performed to evaluate anticoagulation in patients who received bioprosthetic valve replacements at a large teaching hospital from 2014 to 2018. Patients included in this study received either warfarin or a DOAC following bioprosthetic AVR or MVR, and were maintained on the same agent throughout the 6-month follow-up period. The primary efficacy outcome was the incidence of thromboembolic complications and the primary safety outcome was the incidence of major bleeding within 6months following surgery. The rate of readmission was assessed as a secondary endpoint. A total of 197 patients were included; 70 patients received warfarin and 127 patients received a DOAC (apixaban, n = 86; rivaroxaban, n = 40; dabigatran, n = 1). Three patients experienced thromboembolic events, all of which occurred in the DOAC group (0% vs. 2.4%; p = 0.20). Major bleeding occurred in 11 patients-two in the warfarin group and nine in the DOAC group (2.9% vs. 7.1%; p = 0.22). Sixty-one patients were readmitted within the 6-month time frame, with 26 readmissions in the warfarin group and 35 readmissions in the DOAC group (37% vs. 27%; p = 0.16). This small, exploratory study found similar rates of thromboembolic complications and major bleeding events in patients who received a DOAC versus warfarin after a recent bioprosthetic AVR or MVR. This study was limited by its retrospective nature and its sample size. Larger, randomized controlled trials are needed to further determine the efficacy and safety of DOACs in this patient population.