Coronary artery bypass grafting is performed when there is a reduced blood and oxygen supply to the heart. The blockage will be bypassed using a saphenous vein (from your leg) or an internal mammary artery (from your chest). The saphenous vein will be taken from the inner area of your leg. Other vessels in your leg will take over the function of this vein. The length of your leg incision is determined by the length of vessel needed for your bypass.

If your surgeon decides to use the mammary artery to bypass the blockage, only one incision is usually needed. There are two mammary arteries (right and left). These mammary arteries carry oxygenated blood to the heart muscle. This artery will be separated from the chest wall and reattached to the heart's artery below the blockage. When the mammary artery is used, you may experience more chest discomfort after surgery.