Systemic Thrombolysis and Anticoagulation for Early Post-Fontan Thrombosis: A Five-Patient Case Series

BackgroundThrombosis of the Fontan circuit or inferior vena cava (IVC) is an uncommon but serious early postoperative complication that can result in conduit obstruction and hemodynamic compromise. Early detection and timely intervention are critical to prevent Fontan pathway failure.MethodsWe retrospectively reviewed 5 consecutive patients who developed imaging-confirmed venous thrombosis within the first postoperative week following Fontan completion surgery. The cohort included 1 detailed index case and 4 additional cases managed at the same institution. All patients presented with persistent, culture-negative fever between postoperative days 3 and 5. Thrombus location, treatment strategy, and outcomes were analyzed. Systemic thrombolysis was performed using recombinant tissue plasminogen activator (tPA; alteplase; 0.1 mg kg^-1 bolus followed by 0.5 mg kg^-1 h^-1 for 6 h, maximum 50 mg) under continuous unfractionated heparin infusion.ResultsThrombus sites included the IVC (n = 3), iliac veins (n = 1), and extracardiac conduit (n = 1). Three patients-including the index case-received systemic tPA with complete radiological resolution and no bleeding or neurological complications. Two patients were successfully managed with 48 h of heparin infusion alone. Fever subsided within 48 h of therapy, and all patients achieved complete venous recanalization within 2 to 3 days. No patient experienced rethrombosis or major bleeding during 3 to 6 months of follow-up.ConclusionPersistent postoperative fever in a Fontan patient should prompt evaluation for thrombus formation, particularly when infection is excluded. Both short-course systemic thrombolysis and therapeutic heparinization are safe and effective first-line strategies for early post-Fontan thrombosis when applied under strict multimodal monitoring.