809: ANTICOAGULATION IN ADULT ECMO: PERCENTAGE OF TIME IN THERAPEUTIC RANGE WITH HEPARIN OR BIVALIRUDIN

Abstract

Introduction: There is debate regarding optimal anticoagulation strategies in adults receiving extracorporeal membrane oxygenation (ECMO). While unfractionated heparin (UFH) is most utilized, there is increasing use of alternate anticoagulants. This investigation examined the efficacy and safety of UFH versus bivalirudin. Methods: This retrospective, observational study examined adult (age >= 18 years) ECMO patients who received UFH or bivalirudin for systemic anticoagulation in a health system between January 1, 2015 and November 30, 2020. Demographics, lab values, ECMO type, anticoagulation strategy, and clinical outcomes were collected. The primary outcome was percentage of time spent in the therapeutic range, defined by coagulation labs. Secondary outcomes included time to reach therapeutic goal and clinical events. Univariable and multivariable comparisons, controlling for ECMO type and admission period, were performed. Impact of admission period between 2015-2017 and 2018-2020 was analyzed due to changes in anticoagulation practices. Results: There were 118 patients, of whom 39% (n=46) received UFH and 61% (n=72) received bivalirudin. Demographics were similar between groups. More VV ECMO patients were in the bivalirudin group (65%) than in the UFH group (24%) (p< 0.001). Bivalirudin treated patients reached therapeutic range sooner than UFH treated patients (median time 9.3 vs. 16.5 hours, p= 0.0236) although this difference was not significant when controlling for ECMO type and admission period. Bivalirudin treated patients spent a greater percentage of time in therapeutic range compared to UFH treated patients (median 80% vs 24%, p < .0001), an effect that persisted after controlling for ECMO type and admission period (66% vs 39%, p=0.0002). There were no differences between groups in length of stay, days on ECMO, safety outcomes, or inpatient mortality. In multivariable modeling, UFH treated patients received more red blood cell transfusions per ECMO day compared to bivalirudin treated patients (1.40 vs 0.90, p=0.048). Conclusions: A bivalirudin strategy offered more time spent in therapeutic range and fewer blood product transfusions compared to UFH in adult ECMO patients and had similar clinical and safety outcomes. Bivalirudin is a viable anticoagulant for adult patients receiving ECMO.