Heart surgery. Artery (centre) that has been attached to the heart in coronary artery bypass graft (CABG) surgery. Staples, or metal sutures (centre), have been used to hold the artery in place. Forceps (right) are holding part of the heart back to show the artery. During CABG a healthy artery is attached to the diseased coronary artery. This re-routes blood flow, bypassing the blocked coronary artery. Blood vessels can become blocked by the build-up of fatty plaques, atherosclerosis. This reduces blood flow to the heart, leading to heart pain (angina) or a heart attack (myocardial infarction).