Evaluation of Outpatient Anticoagulation Bridging after Left Ventricular Assist Device (LVAD) Implantation

Abstract

Purpose The LVAD is a mechanical circulatory support device that provides hemodynamic support to patients with heart failure. An antithrombotic regimen including warfarin (target international normalized ratio [INR] 2.0-3.0) and aspirin is standard of care following LVAD implantation. The aim of this study is to evaluate the safety of outpatient anticoagulation bridging in the setting of a subtherapeutic INR following LVAD implantation. Methods This study is a retrospective, single-center cohort of adult patients who underwent LVAD implantation (HeartMate II™ or HeartMate 3™). Patients receiving warfarin and at least one dose of therapeutic enoxaparin or fondaparinux for anticoagulation bridging in the outpatient setting between September 1, 2015 and June 30, 2018 were included. The primary endpoint was the incidence of bleeding complications within 1 week of completing the bridging episode. Secondary endpoints included the incidence of new hemolysis or thrombotic events within 30 days, INR at the time of bridge initiation, duration of anticoagulation bridge, and management of bleeding events associated with the bridging episode. Results Data from 160 bridging episodes in 44 patients were analyzed. The majority of patients had implantation of a HeartMate II™ LVAD (93.2%). Enoxaparin was the predominant bridging anticoagulant (97.7%). The primary endpoint occurred during 25 encounters (15.6%) in 14 patients. Of these events, 11 systemic bleeding episodes (6.9%) occurred. Local bleeding complications included injection site bleeding (1.9%), bruising (6.3%), and hematomas (0.6%). The majority of bleeding episodes (81.0%) were self-managed by the patient or with monitoring [INR or bleeding] only. Data analysis of new hemolysis, stroke, and/or thrombosis within 30 days of any bridging episode is ongoing. The mean pre- and post-bridge INRs were 1.63 and 2.58, respectively. The average duration of a bridging episode was 4.6 days (median 3.8). Conclusion Outpatient anticoagulation bridging following LVAD implantation was associated with a modest risk of bleeding complications. The majority of bleeding episodes were localized events treated with self-management only. Results of this study may suggest an overall benefit of bridging during periods of subtherapeutic warfarin therapy following LVAD implantation, pending further data analysis.