Alternate and Emerging Anticoagulation Strategies for Extracorporeal Membrane Oxygenation: A Scoping Review

Background: Unfractionated heparin (UFH) remains the standard anticoagulant for extracorporeal membrane oxygenation (ECMO), despite complications, such as heparin resistance, heparin-induced thrombocytopenia, bleeding and variable pharmacokinetics. This has prompted the search for alternative and novel anticoagulation strategies, including pharmacologic agents, circuit modifications, and monitoring approaches. This scoping review aimed to map the breadth and characteristics of evidence on ECMO anticoagulation strategies beyond UFH. Methods: A comprehensive search of peer-reviewed and gray literature was conducted across PubMed, Cochrane, Clinical Trials, WHO Trials Registry, and conference abstracts through manual searches in key journals. Clinical, pre-clinical, and gray literature studies evaluating pharmacologic agents, anticoagulation-free or heparin-sparing, biocompatible circuits, and monitoring innovations were included. Data were charted and synthesized descriptively to identify trends, gaps, and emerging directions. Results: A total of 269 records were included. Evidence was highly heterogeneous among study designs, populations, ECMO modalities, and outcome definitions. Most clinical studies were retrospective cohorts and adult-centered, with limited multicenter randomized controlled trials and underrepresentation of neonatal and pediatric populations. Direct thrombin inhibitors were frequently studied and clinically implemented alternatives to UFH. Other agents, including nafamostat mesylate, prostaglandin E1, and factor pathway inhibitors remain early in clinical investigation. Anticoagulation-free strategies and biocompatible circuit technologies were mostly supported through pre-clinical and single-center studies. Monitoring and modeling innovations, like TEG, ROTEM, real-time imaging, and machine learning, are quickly emerging. Conclusions: ECMO anticoagulation is transitioning from UFH reliance toward diversified and personalized strategies. Future research should prioritize multicenter randomized controlled trials, standardize protocols, expand to neonatal and pediatric investigation, and integrate strategies.