(143) Heparin Monitoring Strategies in Adult Patients Receiving Extracorporeal Membrane Oxygen Support

Introduction: Anticoagulation is necessary for patients receiving extracorporeal membrane oxygen support (ECMO) due to inflammatory responses from blood exposure to ECMO tubing. Close monitoring of anticoagulation is needed to balance the risk of bleeding versus thrombosis. Currently, there are no guideline recommendations on the optimal anticoagulation monitoring method. This study aims to evaluate which anticoagulation monitoring method, activated clotting time (ACT), activated partial thromboplastin time (aPTT) or anti-Xa, optimizes the percentage of time patients spend within therapeutic range.

Methods: A retrospective, observational study was conducted evaluating anticoagulation monitoring in adult patients who received heparin for anticoagulation while on ECMO from January 2019 to October 2023. Patients were grouped by the anticoagulation monitoring strategy utilized; ACT, aPTT or anti-Xa. The primary outcome was percentage of time patients received anticoagulation that were within the therapeutic goal of the chosen anticoagulation monitoring strategy. Secondary outcomes included major bleeding and thrombotic events, time to therapeutic goal, mortality on ECMO, 30-day mortality and hospital length of stay.

Results: Sixty nine patients were included in the study and grouped based off anticoagulation monitoring strategy, with 4 patients receiving ACT monitoring, 19 patients receiving aPPT monitoring and 46 patients receiving anti-Xa monitoring. For the primary outcome of percentage of time within therapeutic goal, there was no difference amongst the ACT, aPPT and anti-Xa groups (0.39, 0.38, 0.31; p=0.367). There was a statistically significant difference with regards to major bleeding events (0.50, 0.84, 0.61; p=0.05), mortality on ECMO (0.50, 0.56, 0.15; p=0.005), and mortality at 30 days (0.50, 0.63, 0.22; p=0.005), where the anti-Xa group had significantly less events for all three outcomes.

Conclusions: No difference was found for time within therapeutic goal for ECMO patients when comparing heparin anticoagulation monitoring strategies including ACT, aPTT or anti-Xa but patients receiving anti-Xa monitoring had a significantly lower incidence of major bleeding events and mortality.