45: Rescue Thrombolysis with Low-Dose Alteplase for ECMO Canuula Thrombosis Despite Adequate Anticoagulation: A Case Report

Background: Veno-venous extracorporeal membrane oxygenation (VV-ECMO) is an established rescue therapy for patients with severe, reversible respiratory failure. However, thrombotic complications remain a significant concern despite appropriate anticoagulation and can jeopardize circuit function and patient safety. Management options range from anticoagulation adjustment to thrombolytic therapy or circuit exchange, depending on severity and clinical context. Case Presentation: A 41-year-old male with severe ARDS secondary to H1N1 infection and septic shock was initiated on VV-ECMO after failure of conventional therapy and multiple proning sessions. Despite adequate anticoagulation with unfractionated heparin (target ACT 180–200 seconds), he developed rising drainage pressures and reduced ECMO flows. Transesophageal echocardiography revealed large mobile thrombi in the inferior vena cava and superior vena cava cannula tips. The patient was promptly managed with circuit change and pharmacologic thrombolysis was initiated with intravenous alteplase 25 mg over 24 hours, along with heparin infusion. Thrombolysis resulted in partial resolution of the thrombus and improved ECMO flow. The course was complicated by transient hematuria, which resolved upon temporary cessation of alteplase. Systemic anticoagulation was continued thereafter, maintaining circuit stability. Serial echocardiography showed gradual reduction in thrombus size and eventual resolution. Discussion: Cannula-related thrombosis on VV-ECMO can occur despite therapeutic anticoagulation. In select cases, low-dose systemic alteplase can be an effective management strategy when closely monitored for bleeding complications. Conclusion: Systemic thrombolysis with alteplase represents a viable rescue strategy for ECMO cannula thrombosis, offering restoration of circuit function while avoiding surgical intervention, provided it is administered under vigilant multidisciplinary supervision. Keywords: VV-ECMO, Cannula thrombosis, Alteplase, Thrombolysis, ARDS, Extracorporeal life support