Direct oral anticoagulants versus warfarin in adult heart transplant recipients

Background: Direct oral anticoagulants (DOACs) have transformed the field of anticoagulation, offering more predictable pharmacokinetic and pharmacodynamic characteristics when compared to traditional warfarin therapy. DOAC use in the heart transplant population is particularly important to further study due to the high risk of venothromboembolism and the potential for significant drug interactions and altered pharmacokinetics post-transplantation. Methods: A single center, retrospective cohort study was performed in adult heart transplant recipients requiring anticoagulation following transplantation between January 2010 and July 2021. Primary outcomes included incidence of bleeding and breakthrough thromboembolic events. Results: Ninety-five patients met inclusion criteria and out of these patients, 30 (32%) were prescribed warfarin and 65 (68%) were prescribed a DOAC. Seventeen total bleeding events occurred. Bleeding events were significantly more common in the warfarin group compared to the DOAC group (58% vs 41%, p = 0.0077). There was a total of 6 breakthrough thrombotic events in this cohort, all of which were patients on DOAC therapy. Conclusion: DOAC therapy in heart transplant recipients may be safer from a bleeding perspective when compared to warfarin. Additional data to further evaluate the appropriateness for dose modifications for patients with potential drug-drug interactions, higher bleed risk, and unstable renal function are needed to guide optimal practice and dosing strategies in heart transplant recipients.