(141) Low- Versus Standard-Intensity Heparin Protocols in Adult Extracorporeal Membrane Oxygenation

Introduction: Patients maintained on extracorporeal membrane oxygenation (ECMO) require systemic anticoagulation to prevent circuit clotting and systemic thromboembolic complications. The optimal intensity of anticoagulation to balance the risk of bleeding with prevention of thrombotic complications in this patient population is not well described.

Methods: This single-center, retrospective cohort study included adult patients maintained on ECMO who were anticoagulated with our institution’s low or standard intensity heparin protocols. The primary outcome was the incidence of major bleeding events; secondary outcomes included the incidence of minor bleeding events, thrombotic complications, heparin-induced thrombocytopenia (HIT), in-hospital mortality, time in therapeutic range, anti-Xa correlation with aPTT, intensive care unit (ICU) and hospital lengths of stay, oxygenator exchanges, and rate of protocol switching.

Results: Out of 35 patients screened, 27 patients were included with 14 in the low intensity group and 13 in the standard intensity group. The most common indication for ECMO was respiratory failure due to COVID-19, and more patients in both groups were maintained on VV- than VA-ECMO. There was no significant difference in major or minor bleeding events in the low vs. standard intensity groups [6 vs. 4 major bleeds (p=0.69); 4 vs. 5 minor bleeds (p=0.69)]. The median percent subtherapeutic anti-Xa level was significantly higher in the low intensity group vs. the standard intensity group [47% vs. 10% (p=0.019)]. There was no difference between groups with respect to anti-Xa correlation with aPTT; however, correlation was less than 50% in both groups. Seven patients (54%) in the standard intensity group were switched to the low intensity protocol, compared with zero patients in the low intensity group switching protocols (p=0.002). There were no statistically significant differences in any other outcomes.

Conclusions: There was no difference in the incidence of bleeding events when using a low vs. standard intensity heparin protocol in patients maintained on ECMO.