Real-World Comparison of Bleeding and Thrombotic Outcomes in V-V ECMO: Heparin Versus Bivalirudin

Introduction: Extracorporeal membrane oxygenation (ECMO) is associated with significant thrombotic complications necessitating anticoagulation, though optimal strategy remains unknown. We aimed to evaluate thrombotic and hemorrhagic complications with heparin versus bivalirudin use in veno-venous (V-V) ECMO.Methods: We performed a retrospective cohort study of adult patients placed on V-V ECMO with intravenous anticoagulation with either heparin or bivalirudin. Time to thrombotic event (patient-sided thrombus or circuit membrane lung exchange) and major bleed were analyzed in addition to related outcomes.Results: We identified 95 patients placed on V-V ECMO: 61 receiving heparin, 34 bivalirudin. The bivalirudin group were more likely to have severe COVID-19, higher BMI, and longer ECMO duration. Despite this, bivalirudin was associated with reduced risk of thrombotic event (HR 0.14, 95% CI 0.06-0.32, p<0.001) and a significant increase in average lifespan of the circuit membrane lung (16 vs 10 days, p=0.004). While there was no significant difference in major bleeding for the bivalirudin group, these patients required fewer transfusions of packed red blood cells and platelets per 100 ECMO days (means of 13 vs 39, p=0.004 and 5 vs 19, p=0.014, respectively). Lastly, there was significantly improved survival to ECMO decannulation with bivalirudin in univariate analysis (median OS 53 vs 26 days, p=0.015) and a trend towards improved survival after adjusting for influential factors (HR 0.43, 95% CI 0.15-1.24, p=0.120).Conclusions: In this real-world analysis of bivalirudin versus heparin, bivalirudin is a viable option for V-V ECMO and associated with lower risk of thrombotic complications and fewer transfusion requirements.