A patient with exertional angina and left main and two vessel coronary artery disease (left anterior descending and circumflex artery), with normal left ventricular function, underwent elective coronary artery bypass grafting, on extracorporeal circulation. The obtuse marginal branch was considered ungraftable, and a composite arterial graft (left internal mammary anastomosed to the radial artery) was inserted to the distal left anterior descending artery (LAD). After an uneventful operation the patient was transferred to the intensive care on intravenous glyceryl trinitrate. Five hours later, however, he developed ST elevation in leads I, aVL and V1–V5 and became hypotensive. He remained in cardiogenic shock despite systemic inotropes, intramammary papaverine, and intra-aortic balloon counterpulsation. Emergency angiography was performed revealing antegrade flow from the left main artery to the distal LAD. In addition, a moderate stenosis at the anastomosis between the mammary and the radial arteries, possibly as a result of vessel calibre mismatch, was noted, as well as angiographic appearance of systolic compression of the graft by a mediastinal draining tube (right, upper and lower panels). Angioplasty and stenting was performed at the anastomotic site between the mammary and the radial arteries, but despite the excellent angiographic result the ST elevation persisted. Subsequently, the draining tube was removed, resulting in immediate resolution of the ST elevations in the precordial and lateral leads. Left coronary artery angiography revealed cessation of antegrade filling to the distal LAD. The creatine phosphokinase peaked at 471 ng/ml the following day and echocardiography revealed a left ventricular ejection fraction of 60% with mild anteroapical hypokinesis. The ECG, before discharge on the 12th postoperative day, was remarkable for Q waves only in leads V1–V2.

The draining tube crosses the course of the arterial graft in systole (upper panel) and diastole (lower panel), causing systolic compression. Proximal to the crossing point, a moderate stenosis at the anastomosis between the mammary and the radial arteries is also shown.