A Case of Giant Left Circumflex Coronary Fistula Aneurysm with Unidentified Fistula.

A coronary aneurysm is a rare type of cardiovascular disease. We report a case of a 53-year-old male patient who presented to our hospital with a giant left circumflex coronary fistula aneurysm (LCCA) (75 mm × 70 mm). Since coronary angiography and coronary computed tomography angiography failed to detect the fistula of the coronary aneurysm, interventional occlusion surgery could not be performed. We discovered the fistula in the right atrium by anterograde perfusion with blood-containing myocardial protective fluid after switching to intraoperative exploration during cardiac surgery. The coronary aneurysm's fistula and inlet were then sutured, and the aneurysm was resected. The patient recovered successfully after the operation. This case was instructive in managing LCCA, especially with an unidentified fistula.