Evaluation of enoxaparin for bridging of warfarin in outpatients with left ventricular assist devices (LVADs)

BACKGROUND

Patients with left ventricular assist devices (LVADs) require systemic anticoagulation. The use of enoxaparin for bridging to warfarin remains understudied in this population.

METHODS

This single-center retrospective study was performed to characterize enoxaparin use and associated thrombotic and bleeding outcomes in adult outpatients with LVADs from January 2018 to July 2021.

RESULTS

Fifty-four enoxaparin bridging events were evaluated in 49 patients. Most patients with HeartMate II (HM2) and HeartWare (HVAD) devices received enoxaparin dosed 1 mg/kg every 12 h. In patients with HeartMate 3 (HM3) devices, an equal number of patients received 0.5 mg/kg every 12 h and 1 mg/kg every 12 h, with a smaller subset receiving intermediate doses. The median duration of bridging was 6 days (4-8 [IQR]). One major bleeding event required discontinuation of enoxaparin and hospitalization in a patient with an HM3 device. Thrombotic events occurred in four patients with two incidents of pump thrombosis requiring pump exchange and two ischemic strokes. All thrombotic events occurred in patients with HVAD or HM2 devices.

CONCLUSION

These results suggest that enoxaparin bridging in LVAD patients was well-tolerated with low bleeding and thrombotic rates, particularly with the HM3 device.

Hydroxocobalamin Versus Methylene Blue for the Treatment of Vasoplegic Shock Associated With Cardiopulmonary Bypass

OBJECTIVES

To compare changes in vasopressor requirements and hemodynamic responses after hydroxocobalamin or methylene blue administration for vasoplegic shock (VS).

DESIGN

Retrospective cohort analysis.

SETTING

Single-center, academic medical center.

PATIENTS

Cardiothoracic surgery adult patients.

INTERVENTIONS

Hydroxocobalamin or methylene blue.

MEASUREMENTS

The primary outcome was a change in vasopressor requirements over the first 24 hours (1, 3, 6, 12, and 24 hours) after hydroxocobalamin or methylene blue initiation. Secondary outcomes included changes in mean arterial pressure (MAP), systemic vascular resistance, and lactate.

MAIN RESULTS

A total of 120 adult patients who received hydroxocobalamin (n = 77) or methylene blue (n = 43) were included. Vasopressor requirements at baseline were 0.34 µg/kg/min (95% CI 0.28-0.4) norepinephrine equivalent (NEE) in the hydroxocobalamin group, and 0.59 µg/kg/min (95% CI 0.52-0.66) NEE in the methylene blue group; p < 0.001. Vasopressor requirements decreased significantly at each time point within each group (hour 1 mean [95% CI] NEE, hydroxocobalamin 0.27 µg/kg/min [0.21-0.33]; methylene blue 0.44 µg/kg/min [0.38-0.51]; p < 0.001). The mean MAP at baseline was 65 mmHg (95% CI 63-67) in the hydroxocobalamin group, and 57 mmHg (95% CI 54-59) in the methylene blue group; p < 0.001. The mean MAP increased significantly from baseline at each time point within each group (hour 1 mean [95% CI] hydroxocobalamin 73 mmHg [71-75]; methylene blue 67 mmHg [65-70]; p < 0.001). After adjusting for baseline characteristics, a significantly greater reduction in vasopressor requirements and an increase in MAP were noted in the hydroxocobalamin group compared with the methylene blue group.

CONCLUSIONS

Hydroxocobalamin was associated with a greater reduction in vasopressor requirements than methylene blue in treating VS associated with cardiopulmonary bypass.