Warfarin-Aspirin Therapy in Congenitally Corrected Transposition of the Great Arteries After Lateral Tunnel Fontan

BACKGROUND: Fontan circulation carries high risk of thromboembolic complications, and optimal anticoagulation strategies in pediatric patients remain controversial. CASE SUMMARY: A 13-year-old adolescent boy with dextrocardia, congenitally corrected transposition of the great arteries, ventricular septal defect, and pulmonary stenosis underwent staged surgical palliation including a bidirectional Glenn shunt followed by the lateral tunnel Fontan procedure. Postoperative echocardiography demonstrated a functioning Fontan circulation with reduced right ventricular systolic dysfunction and mild-to-moderate tricuspid regurgitation. The patient developed postoperative tachycardia (heart rate ∼150 beats/min), for which oral digoxin was initiated during hospitalization. Given the prothrombotic nature of Fontan physiology, long-term anticoagulation with warfarin, along with aspirin, was commenced, and over time, no thromboembolic events occurred during 6-month follow-up. DISCUSSION: Patients with systemic right ventricles and Fontan physiology represent a high-risk subgroup for thrombosis. Individualized anticoagulation strategies are essential. TAKE-HOME MESSAGE: Warfarin, along with aspirin, can be safely implemented in selected patients with high-risk Fontan.