Case report
A 63-year-old woman presented with chest discomfort. Coronary angiography revealed vasospastic angina, and transthoracic echocardiography (TTE) showed a giant ASA without a PFO, interatrial shunt or mitral valve prolapse. Cardiac multidetector computed tomography and cardiac magnetic resonance imaging showed that the giant ASA protruded about 30 mm into the right atrium and that a thrombus was attached to the left side of the ASA pouch (Fig. 1A and B). The patient was started on nicorandil, aspirin and anticoagulation therapy. Electrocardiographic monitoring detected occasional paroxysmal atrial tachycardia. We recommended surgical resection of the ASA because the patient was at risk for systemic thrombosis, so following procedure was performed. The ASA was surgically repaired via a median sternotomy under a cardiopulmonary bypass. The ASA visualized through a right atriotomy, protruded into the right atrium (Fig. 2A). A PFO was also evident next to the ASA (Fig. 2B). The aneurysm was excised, and the defect was closed with a pericardial patch using 4-0 polypropylene sutures. No thrombus remained attached to the surface of the resected ASA. The postoperative course was uneventful, and postoperative TEE did not detect a shunt, so the patient was discharged on postoperative day 26 with normal sinus rhythm. Macroscopic assessment of the ASA showed a mixture of normal and very thin tissues that seemed vulnerable to imminent tearing (Fig. 3A). Pathological assessment of the resected ASA showed that the thick tissues comprised a mixture of infiltrative fatty cells and fibrosis (Fig. 3B and C). The patient is under followup as an outpatient and remains free of complications at ten months postoperatively.