CONGRESS ABSTRACT

Background: Coronary artery fistulas are rare anomalies; when associated with ectasia/aneurysm of the feeding vessel, anatomic definition and estimation of hemodynamic impact require multimodality imaging. Case presentation: A 66-year-old asymptomatic man was electively admitted for a follow-up exercise treadmill test, which was considered equivocal for stress-induced ischemia. He had no prior cardiac history; family history was positive for coronary artery disease in his father. Cardiovascular risk factors included arterial hypertension and hyperlipidemia. Invasive coronary angiography showed ectatic disease of the left main coronary artery and circumflex artery, with arteriovenous fistulization that on angiographic projections suggested drainage toward the right atrium or inferior vena cava region. A mild stenosis of the proximal left anterior descending artery was also reported; the right coronary artery had no significant stenoses and coronary dominance was balanced. The circumflex supplied only two small obtuse marginal branches and a small posterior interventricular branch. Coronary CT angiography confirmed ectasia of the left main (10 mm) and circumflex (9 mm) and excluded significant coronary stenoses. Distally, the circumflex gave rise to a large fistula (maximum diameter approximately 20 mm) draining into the coronary sinus. Transthoracic echocardiography showed normal cardiac morphology and function without signs of right-sided volume overload; with color Doppler, the ectatic left main and the circumflex course could be visualized along their trajectory. The patient was discharged in good clinical condition with a plan for clinical and imaging follow-up. Discussion/Conclusions: Circumflex-to-coronary sinus fistulas are uncommon and may yield positive provocative tests even in the absence of obstructive stenosis, possibly due to coronary steal. Integrating invasive angiography, coronary CT angiography and echocardiography enables accurate delineation of anatomy and hemodynamic relevance of the malformation, supporting individualized management and follow-up.