MODEL RELEASED. Elderly man in coronary care unit following aorto-coronary by-pass surgery, showing a physiotherapist examining his chest with a stethoscope. Coronary by-pass surgery counts as one of the great successes of modern surgical medicine. Inefficient coronary arteries, blocked by the accumulation of atheroma plaques (coronary artery disease) may be replaced by venous grafts, usually taken from the saphenous vein of the leg. Additionally, the internal mammary artery, which supplies the chest wall, may be dissected & re- routed to boost the supply of blood to the heart muscle.