Thrombotic Occlusion of Giant Circumflex Artery Aneurysm After Ligation of Arteriovenous Fistula

A 39-year-old man with no significant past medical history and no conventional coronary risk factors presented with a history of gradually progressive exertional dyspnea and a systolic heart murmur. Chest x-ray showed an enlarged cardiac silhouette with pulmonary plethora. Initial assessment by transthoracic echocardiography demonstrated mild mitral regurgitation but also revealed an enlarged coronary sinus with abnormal Doppler flow patterns in the right atrium. A subsequent transesophageal echocardiogram demonstrated a large, serpiginous coronary artery fistula from the dominant left circumflex artery to the coronary sinus causing aneurysmal dilatation of the left circumflex artery extending back to the left main stem (maximum cross-sectional diameter, 17 mm). No other congenital heart defects were identified. A 64-slice multidetector computed tomography (GE Lightspeed VCT, Chalfront St Giles, Buckinghamshire, UK) coronary angiogram confirmed the transesophageal echocardiographic findings and demonstrated that the left anterior descending …