CABG is performed by a cardiac surgeon to bypass a block in one of the arteries leading to the heart muscle. It is performed by installing a transplant - a piece of a vessel (artery or vein), previously taken, for example, from the saphenous vein of the leg, which is attached to the affected coronary artery in order to create a new path through which blood will flow without blocking.

Traditionally, to bypass the blocked coronary artery, your doctor makes a large incision in the chest and temporarily stops the heart. To open the chest, your doctor cuts the breastbone (sternum) in half lengthwise and spreads it apart. Once the heart is exposed, your doctor inserts tubes into the heart so that the blood can be pumped through the body by a heart-lung bypass machine. The bypass machine is necessary to pump blood while the heart is stopped.