Usefulness of intraoperative transesophageal echocardiography for evaluation of circumflex coronary artery fistula with ruptured aneurysm draining into coronary sinus.

A coronary artery aneurysm (CAA) is defined as dilatation of a coronary artery to a diameter >1.5 times that of the adjoining normal coronary artery. Giant CAAs with a diameter ≥ 50 mm are quite rare. Coronary artery fistulas are also uncommon, and affected patients require prompt diagnosis and treatment. Coronary angiography is the most common method of diagnosing coronary artery fistulas; however, transesophageal echocardiography (TEE) can also be a key intraoperative tool. In the present report, we describe the case of an 83-year-old man urgently admitted to our hospital with pericardial tamponade. Enhanced computed tomography and coronary angiography revealed a bulging left main and circumflex artery that was connected to a 50-mm diameter CAA. Emergency intraoperative TEE clearly showed a CAA with a surrounding hematoma, bulging circumflex artery, and a fistulous connection to the coronary sinus; the fistulous vessel contained a thrombus. Surgical repair was successful. This case demonstrates that CAA can rupture because of spontaneous closure of a thrombus-containing fistula and that intraoperative TEE could help to clearly identify the location of the CAA and fistulous connection.