Successful use of nafamostat mesilate anticoagulation in V-V ECMO for refractory diffuse alveolar hemorrhage secondary to ANCA-associated vasculitis: case report and review of the literature

Diffuse alveolar hemorrhage (DAH) is a life-threatening complication of Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). Veno-venous extracorporeal membrane oxygenation (V-V ECMO) serves as a salvage respiratory support for patients with severe hypoxemia unresponsive to conventional mechanical ventilation. However, anticoagulation management during ECMO remains particularly challenging in the presence of active alveolar hemorrhage. We report a 43-year-old woman with myeloperoxidase-ANCA-positive microscopic polyangiitis who presented with acute kidney injury and life-threatening DAH. Despite maximal therapy, including high-dose corticosteroids, plasma exchange, cyclophosphamide, and lung-protective ventilation in the prone position, the patient developed refractory hypoxemia with a nadir ratio of arterial oxygen partial pressure to fractional inspired oxygen (PaO₂/FiO₂) of 38.6 mmHg. V-V ECMO was initiated with nafamostat mesilate, an ultrashort-acting serine protease inhibitor, for relative systemic anticoagulation sparing (initial dose 0.61 mg/kg/h, maximum dose 2.0 mg/kg/h; target post-oxygenator activated partial thromboplastin time (APTT) 50–70 s). During 11 days of ECMO support, no fatal bleeding or clinically significant circuit thrombosis occurred. Alveolar hemorrhage resolved completely, and the patient was successfully weaned from ECMO and subsequently liberated from mechanical ventilation. This case suggests that nafamostat mesilate is a feasible and relatively safe anticoagulation option for V-V ECMO in patients with AAV who have active DAH, providing a clinically applicable dosing and monitoring strategy for this high-risk clinical scenario.