Tandem aneurysms of an internal mammary-aortocoronary bypass graft

A 69-year-old male patient was admitted to the accident and emergency department at Klinikum Braunschweig (Germany) because of recurrent upper gastrointestinal bleeding. Upper gastrointestinal endoscopy revealed a duodenal ulcer which was treated by coagulation. Thereafter, the patient was admitted to the intensive care unit for blood transfusions and observation. His past medical history included aortic valve replacement 13 years ago as well as aortocoronary bypass surgery 17 years earlier with an internal mammary artery graft to the left anterior descending artery and two further venous bypass grafts; carotid endarterectomy for symptomatic stenosis was performed at the same time. His cardiovascular risk factors included hyperlipidaemia and arterial hypertension. Upon his admission to the intensive care unit, a chest radiograph was obtained, which showed a well-defined soft tissue-density mass, apparently arising from the left heart border (figure 1). An echocardiogram did not yield further information and a contrast mediumenhanced chest CT was therefore arranged for further evaluation. A helical acquisition using a 16-slice scanner (Siemens Somatom 16, Siemens Medical Systems, Erlangen, Germany) revealed a tandem aneurysm of the internal mammary artery bypass graft (figure 2): more proximally, a small, non-perfused aneurysm with a maximum diameter of 2.2 cm and, distally, a second aneurysm with a maximum diameter of 5.7 cm, corresponding to the pericardial mass on the chest X-ray. The larger aneurysm was partly perfused. On the thin-section primary reconstructions the connection between the larger aneurysm and the internal mammary artery could be seen. Formal catheter coronary arteriography provided no additional information regarding the aneurysms; specifically, no further aneurysm of a coronary artery was detected. Both the venous bypass grafts were occluded. Despite being asymptomatic, an operative revision was advised. Intraoperatively, the aneurysms of the internal mammary artery bypass were confirmed and could be resected. The patient made an uneventful recovery and could leave hospital for rehabilitative therapy soon thereafter. …