Retrospective,Single-Center Cohort Study of Bivalirudin Compared to Unfractionated Heparin in Patients Receiving Extracorporeal Membrane Oxygenation

Abstract

Background:

Extracorporeal membrane oxygenation (ECMO), a form of temporary mechanical circulatory support, causes a prothrombotic state due to activation of inflammatory processes via exposure of blood to the circuit. Systemic anticoagulation is recommended to prevent thrombosis. Unfractionated heparin (UFH) and direct thrombin inhibitors (DTIs) are anticoagulant agents that inactivate thrombin; however, UFH requires antithrombin III (ATIII) for its activity, and patients supported by ECMO are at risk for acquired ATIII deficiency. In addition, heparin may cause heparin-induced thrombocytopenia, complicating therapy. Guidelines on anticoagulant use in ECMO reference UFH as a recommended agent with DTIs as an alternative option. Meta-analyses comparing the 2 agents in ECMO have evaluated efficacy and safety; however, discordant results prompt the need for additional research.

Objective:

The objective of this study is to evaluate differences in bleeding and thrombotic events between UFH and bivalirudin for anticoagulation during ECMO support.

Methods:

This study is a retrospective, single-center cohort study conducted at a primary ECMO center and a tertiary academic medical center.

Results:

Bleeding and systemic thrombosis rates were not different between bivalirudin and UFH (30 vs 33 events, hazard ratio [HR] = 0.89; 95% confidence interval [CI] = 0.55-1.47, P = 0.7; 12 vs 17 events, HR = 0.68; 95% CI = 0.32-1.42, P = 0.3); however, when controlled for covariates, device thrombosis was lower with bivalirudin (30.2% vs 43.4%, P = 0.017). Time in therapeutic range (TTR) was higher with bivalirudin (69.98% vs 55.5%, P < 0.001).

Conclusion and Relevance:

When compared to heparin, bivalirudin for anticoagulation in ECMO was associated with a decreased rate of device thrombosis and greater TTR.