Low-molecular-weight heparin for anti-coagulation after left ventricular assist device implantation

BACKGROUND: Anti-coagulation is required in patients with left ventricular assist devices (LVADs). We evaluated the feasibility of low-molecular-weight heparin (LMWH) for initiation of anti-coagulation and transitioning to oral anti-coagulation after LVAD implantation. METHODS: This single-center study included 78 consecutive patients who underwent either Thoratec HeartMate II LVAD (n = 27) or HeartWare ventricular assist device (HVAD, n = 51) implantation. The LMWHs enoxaparin (n = 50) and dalteparin (n = 28) were used. LMWH was started within 24 hours post-operatively in 79.5% of patients. No anti-coagulation was given before starting LMWH therapy. LMWH activity was monitored by determination of anti factor Xa levels in plasma. RESULTS: The majority of patients (80.7%) had peak anti-Xa activity within the defined range of efficacy of 0.2 to 0.4 IU/ml by the second day of treatment. Mean effective peak anti-Xa activity was 0.28 +/- 0.06 IU/ml. Mean duration of anti-coagulation with LMWH was 25.8 +/- 18 days. Ischemic strokes were observed in 3 patients (3.8%), with a total of 4 events. Three events occurred while on LMWH, and 1 event occurred during follow-up on oral anti-coagulation. There was 1 fatal stroke. No pump thrombus was observed. Major bleeding was observed in 5 patients (6.4%), with a total of 6 events. Gastrointestinal bleeding was the most common complication (n = 3). There were no fatal bleeding events. CONCLUSIONS: LMWH in the setting of LVAD shows rapid and constant biologic efficacy. Anticoagulation with LMWH appears feasible after LVAD implantation. These findings support further evaluation of LMWH as an alternative to unfractionated heparin in this patient cohort. (C) 2014 International Society for Heart and Lung Transplantation. All rights reserved.