Activated Partial Thromboplastin Time Versus Anti-Factor Xa Monitoring of Heparin Anticoagulation in Adult Venoarterial Extracorporeal Membrane Oxygenation Patients

The preferred assay for measuring and adjusting unfractionated heparin (UFH) infusion to achieve optimal outcomes during extracorporeal membrane oxygenation (ECMO) is not well established. This retrospective cohort study explored safety and efficacy outcome differences between anti-factor Xa (anti-Xa) and activated partial thromboplastin time (aPTT) for UFH in adult venoarterial ECMO. Forty-one patients were included and analyzed. The UFH rate at first goal and time to goal were both higher in the aPTT versus anti-Xa cohort but did not achieve statistical significance (12.14 vs. 9.58 unit/kg/hour (p = 0.29), 20.22 vs. 12.05 hours (p = 0.11)). The aPTT cohort was in target goals 35.0% of the time versus 47.7% in the anti-Xa cohort (p = 0.13), above goal 41.0% vs. 17.3% (p = 0.02), and below-goal 24.0% versus 35.0% of the time (p = 0.34). Minimum heparin rates in the aPTT cohort were 6.28 vs. 3.33 unit/kg/hour in the anti-Xa cohort (p = 0.07), and the maximum UFH rate was 18.77 unit/kg/hour vs. 15.48 unit/kg/hour (p = 0.10). Our findings suggest that aPTT monitoring may result in a delay to target attainment, higher UFH rates, and overall exposure.