Directly to a DOAC? Safety of Alternatives to Warfarin for Anticoagulation in Heart Transplantation

Purpose Managing venous thromboembolism (VTE) and Atrial Fibrillation (AF) with warfarin can be difficult given the frequent need to hold anticoagulation for procedures performed; however there is limited evidence on the safety and efficacy of direct-acting oral anticoagulants (DOAC) in HTx recipients. Methods Single-center, retrospective study of all HTx recipients who received oral anticoagulation between January 2010 and August 2018. Patients were classified according to warfarin vs DOAC use and their baseline characteristics were compared using Student's t test or chi-square test where appropriate. We compared bleeding among groups, defined as any significant blood loss requiring discontinuation of anticoagulation within the first year of treatment using univariable logistic regression. We assessed survival after initiation of anticoagulation among groups using Kaplan-Meier curves and the log-rank test. Results Among 426 HTx recipients screened, 80 patients were intitiated on oral anticoagulation for VTE in 75 (94%) and AF in 5 (6%) cases. Overall, warfarin was used in 27 (34%) and DOAC in 62 (78%) cases of whom 36, 21 and 5 were on apixaban, dabigatran and rivaroxaban, respectively. The median (IQR) time to initiation of warfarin and DOAC were respectively 61 (26-267) and 33 (16-135) days following HTx. Baseline characteristics showed more women, lower GFR and higher dialysis use in the warfarin group. Warfarin was associated with a significant increase in bleeding (OR 4.55, 95% CI 1.2 to 16.2), as well as bleeding requiring blood products (OR 7.6, 95% CI 1.4 to 42.8). There was no difference in overall survival between groups (logrank P = NS). No bleeding complications occurred following endomyocardial biopsy. Conclusion This is the largest cohort of HTx recipients treated with oral anticoagulants. Patients selected for DOAC had better baseline renal function than those treated with warfarin, but there were no differences in subsequent survival or procedural complications.