Safety of Traditionally Dosed Enoxaparin in Patients Supported with Left Ventricular Assist Devices

Purpose Existing data on enoxaparin use in left ventricular assist device (LVAD) patients are limited. This analysis evaluates the use and impact of enoxaparin on major bleeding events in LVAD patients. Methods This was a retrospective cohort study of LVAD patients managed by a single non-transplanting center. The primary endpoint was the rate of bleeding during or within 14 days of enoxaparin therapy as compared to the rate of non-enoxaparin related bleeding. Secondary endpoints included risk factors for enoxaparin-related bleeding and the impact of enoxaparin use on thrombotic events. The center's standard protocol is to bridge for an INR of 1.6 or lower with enoxaparin 1.5 mg/kg once daily or 1 mg/kg twice daily for patients >120 kg. Results A total of 151 patients were followed for an average of 1.9 years. Ninety patients (56.6%) received enoxaparin bridge therapy 351 times with an average daily dose of 1.48 mg/kg and average duration of 5.4 days per bridge episode. Enoxaparin-related bleeding occurred in 13 patients (13 events; 0.07 events/patient/year) while 72 patients experienced non-enoxaparin bleeding events (176 events; 0.62 events/patient/year). Compared to patients who received enoxaparin but did not experience bleeding, patients who experienced enoxaparin-related bleeding were more likely to have a mechanical mitral valve (15% vs 0%, p=0.02) and a higher baseline INR (1.68 vs 1.52, p=0.04). Duration of bridge therapy, dose, indication, and renal function were similar between groups (see table). For the entire cohort, 27 patients experienced 35 thrombotic events (0.12 events/patient/year), the majority of which were admissions for elevated LDH. Five of the 6 thrombotic events that occurred during enoxaparin therapy were admissions when an elevated LDH failed to improve with enoxaparin. Conclusion Traditionally dosed enoxaparin was shown to be safe as bridge therapy in patients supported by LVADs. Enoxaparin-related bleeding was uncommon and occurred less often than overall bleeding.