Coronary steal through anomalous internal mammary artery graft. Treated by ligation without sternotomy.

A patient who had undergone adequate coronary revascularization with a left internal mammary artery graft to the left anterior descending coronary artery and with saphenous vein grafts to the right coronary artery and to the 1st and 2nd obtuse marginal branches presented with early-onset recurrent angina. A repeat angiogram showed an abnormally large branch arising from the very proximal segment of the left internal mammary artery and supplying the whole lateral chest wall via many intercostal tributaries. Relief of symptoms was achieved by ligation of this branch, and the patient remains symptom free more than 6 years after the procedure.