Safety and Efficacy of Warfarin Alone for the Prevention of Hemocompatability-Related Adverse Events in Patients with a HeartMate III™ Left Ventricular Assist Device

Purpose Patients implanted with a HeartMate III™(HM3) LVAD have significantly less thrombotic events than other LVADs, but comparable rates of bleeding. Our institution recently eliminated aspirin (ASA) regardless of indication from the postoperative antithrombotic regimen of patients receiving a HM3 to minimize bleeding. This study seeks to compare the rates of bleeding and thrombotic events in patients with a HM3 who received warfarin alone to those who received warfarin and ASA. Methods A retrospective review was performed to identify patients receiving a HM3 LVAD at our institution from July 1, 2015 through March 30, 2020. Data was collected from the date of LVAD implantation until first bleeding or thrombotic event, death, transplant, or the end of study period. Patients with known hypercoagulable state, that died before discharge, or were on triple therapy with ASA, warfarin and a P2Y12 inhibitor were excluded. The primary outcome was a composite of bleeding and thrombotic events, termed hemocompatibility-related adverse events (HRAE). Results A total of 81 patients were included in the analysis. Fifty-three patients received both warfarin and ASA post-LVAD, and 28 patients who received warfarin but no ASA post-LVAD. During a median follow up of 285 days, a primary outcome event occurred in 23 of 53 patients (43.4%) in the ASA group and in 3 of 28 patients (10.7%) in the no-ASA group (hazard ratio for HRAE, 3.11; 95% confidence interval [CI] 0.92 - 10.59, p = 0.0691). Bleeding events occurred less frequently in the no-ASA group than in the ASA group (7.1% vs 32.1%, OR 0.17 95% CI 0.02 - 0.80, p = 0.01309). The incidence of thrombotic events was not significantly different between the no-ASA group and ASA group (0% vs. 9.4%, respectively, OR 0.00, 95% CI 0 - 2.02, p = 0.1582). Conclusion The complete omission of ASA from the antithrombotic regimen of patients with a HM3 LVAD was associated with less bleeding events without an increase in thrombotic events.