Late Thrombosis With Ischemia After Left Main Coronary Artery Fistula Closure

BACKGROUND: Coronary artery fistulae are rare congenital or acquired anomalies, comprising <0.2% of congenital cardiac malformations. Surgical closure is the gold standard for complex or high-flow fistulae, typically via direct chamber closure or tract ligation. CASE SUMMARY: We report a left main coronary-to-right atrial fistula in a patient with Factor VII deficiency. Given the deep intramediastinal course and heightened bleeding risk, we performed right atrial egress patch closure with mid-fistula ligation rather than extensive resection. Although this strategy minimized operative complexity, the patient later developed a left main coronary aneurysm with late thrombosis, raising concern that a more aggressive initial repair may have reduced long-term risk. DISCUSSION: This rare presentation highlights the surgical dilemma between procedural safety and definitive repair. TAKE-HOME MESSAGES: Operative planning must balance bleeding risk against durable reconstruction. The management of residual coronary aneurysms after fistula closure remains uncertain.