Bivalirudin Versus Heparin for Anticoagulation in Extracorporeal Membrane Oxygenation

ABSTRACT

INTRODUCTION: Anticoagulation is critical in preventing thrombosis in extracorporeal membrane oxygenation (ECMO). Unfractionated heparin (UFH) has historically been the anticoagulant of choice;however, is limited by a co-factor to assert its action that leads to fluctuations in dose responsiveness and complications like heparin-induced thrombocytopenia and heparin resistance. For these reasons, use of direct thrombin inhibitors is increasing in ECMO. The purpose of this study is to compare the efficacy and safety of UFH vs. bivalirudin for anticoagulation in ECMO with a subset of COVID-19 patients. METHOD(S) This was a retrospective, single-centered, cohort study of patients receiving UFH (n=106) vs. bivalirudin (n=27) for ECMO. The primary outcome was the percentage of thrombotic events (in-circuit, non-circuit related thrombosis) during ECMO between patients receiving UFH and bivalirudin. RESULT(S) There were significant differences between bivalirudin and UFH patients with the following baseline characteristics BMI (29.9 vs. 26.5;p=0.02), Caucasian race (29.6% vs. 65.1%;p< 0.01), positive COVID-19 status (66.7% vs. 0.9%;p< 0.01), and indication for ECMO (respiratory failure 100% vs. 67.9%;p< 0.01). The time to goal anticoagulation was longer in bivalirudin patients (7.1 vs. 25.0 hr;p< 0.01). COVID-19 patients had greater thrombotic events (47.4% vs. 25.4%;p=0.05), number of bleeding events per patient (2 vs.1;p< 0.01), as well as longer ECMO duration (42.2 vs. 6.6 days;p< 0.01), length of ICU (46.4 vs. 6.6 days;p< 0.01) and hospital stay (52.1 vs. 33.2 days;p=0.03) compared to non-COVID-19 patients. A sub-group analysis of venovenous (VV) ECMO, non-COVID-19 patients was propensity score matched by age, sex, Caucasian race, BMI, and ECMO duration. This analysis demonstrated no significant differences between UFH and bivalirudin in thrombotic or bleeding events, however, there was greater mortality in the UFH arm (100% vs. 28.6%;p=0.02). CONCLUSION(S) Patients with COVID-19 experienced greater thrombotic and bleeding events, with longer ECMO duration and lengths of stay. In the propensity matched analysis comparing UFH vs. bivalirudin in VV-ECMO, non- COVID-19 patients, there were no significant differences between thrombotic or bleeding events, but significantly greater mortality in the UFH arm.