Is systemic anticoagulation necessary during intraoperative venoarterial extracorporeal membrane oxygenation for bilateral lung transplantation? A feasibility study comparing zero-, low-, and high-intensity heparin strategies.

Objective: Optimal anticoagulation during bilateral lung transplantation (BOLTx) supported with venoarterial extracorporeal membrane oxygenation (VA-ECMO) remains uncertain. We compared outcomes among zero-heparin (ZH), low-intensity heparin (LIH), and high-intensity heparin (HIH) strategies during intraoperative VA-ECMO-supported BOLTx. Methods: A retrospective pilot study of 59 consecutive patients undergoing BOLTx with intraoperative VA-ECMO at Vanderbilt University Medical Center between November 1, 2024, and May 1, 2025, was performed. Patients were stratified according to intraoperative anticoagulation strategy: ZH (no intraoperative anticoagulation; n = 22), LIH (single bolus ≤2000 units without continuous infusion; n = 16), and HIH (single bolus >2000 units followed by heparin infusion 200-500 units/hour; n = 21). The primary outcome was thromboembolic events within 90 days after transplantation, including stroke, myocardial infarction (MI), pulmonary embolism, deep venous thrombosis (DVT), and intraoperative vascular anastomotic thrombosis. Secondary outcomes included estimated blood loss, transfusion requirements, extracorporeal membrane oxygenation circuit thrombosis, primary graft dysfunction at 72 hours, hospital length of stay, and in-hospital mortality. Results: Of the 59 patients, 31 (52.5%) experienced thromboembolic complications within 90 days (HIH: 14/31, 45.2%; LIH: 9/31, 29% and ZH: 8/31, 25.8%). This included 26 DVTs (HIH:11, LIH: 8, ZH:7) detected on routine surveillance imaging at POD 7. Therapeutic anticoagulation for DVT was initiated for 8 of 11 in the HIH, 5 of 8 in the LIH and 4 of 7 in the ZH groups Two patients had strokes (HIH: 1 on POD 11, LIH: 1 on POD 83), 2 patients with pre-existing coronary artery disease experienced an MI (HIH:1 on POD 1, ZH:1 on POD 3) that required PCI, and 1 patient had evidence of an intraoperative vascular anastomotic clot (HIH: 1) that was easily flushed out after lung reperfusion. No extracorporeal membrane oxygenation circuit or oxygenator thrombosis were noted in any of the groups. Operative duration and transfusion requirements for red blood cells and fresh frozen plasma were greater in the HIH group ( Conclusions: In this single-center cohort, intraoperative VA-ECMO without heparin was feasible and was not associated with an observed increase in early thromboembolic events compared with other anticoagulation strategies. Larger prospective studies are warranted.