Enoxaparin Use and Adverse Events in Outpatients With a Continuous Flow Left Ventricular Assist Device at a Single Institution

Abstract

Background: Patients with left ventricular assist devices (LVADs) are anticoagulated with warfarin and may receive enoxaparin bridging for a subtherapeutic international normalized ratio (INR). There is no guideline regarding enoxaparin bridging in LVAD patients and a dosing strategy to ensure efficacy and safety is uncertain. Objective: The objective was to characterize the use of enoxaparin bridging for subtherapeutic INRs and its impact on thrombotic or major bleeding events (MBE) in patients with an LVAD. Methods: A retrospective review from 6/1/17 to 6/30/18 was performed. Patients with an LVAD were excluded if they had less than 60 days of outpatient anticoagulation or age <18 years old. Patients were divided into 2 cohorts based on enoxaparin exposure. MBE and thrombotic events were classified as related to enoxaparin if events occurred while receiving enoxaparin and up to 7 days or 30 days, respectively, after discontinuation. Results: Seventy-one LVAD patients met inclusion criteria and 50 patients received enoxaparin bridging. Therapeutic-dose enoxaparin was initiated at a mean INR of 1.8 for a mean duration of 2.8 days. In the enoxaparin exposure group, one MBE occurred 6 days after enoxaparin discontinuation, coinciding with an INR increase from 1.8 to 4.7. One thrombotic event occurred 2 days after enoxaparin discontinuation at an INR of 5.0. Conclusion: This institution’s bridging strategy of therapeutic-dose enoxaparin with a short duration has a low rate of bleeding and thrombotic events. Additional prospective studies of anticoagulation bridging based on characteristics such as type of LVAD device are warranted.