Coronary artery bypass surgery, also called CABG (pronounced “cabbage”), improves the flow of blood to the heart muscle when your coronary arteries are severely narrowed or blocked by plaque. Plaque is a buildup of fats, cholesterol and other substances in the walls of the arteries.
During bypass surgery, blockages are not removed. Rather, a new pathway is created around the blocked part of a coronary artery. The operation involves taking blood vessels from other parts of your body and attaching them to the coronary arteries beyond the blockage. This is the bypass graft. The blood is then able to flow around, or bypass, the blockages. If more than one artery is blocked, you may need multiple bypasses.
Reaching the heart
Coronary artery bypass surgery is performed by a team of surgeons. While one surgeon is getting the graft—from a vein in your leg, an artery in your arm or an artery in your chest wall—another surgeon will make an incision in your chest and divide your breastbone. In most cases, you will be supported by a heart-lung machine that will do the work of your heart and lungs during surgery. Blood is circulated through the heart-lung machine, and the machine supplies the blood with oxygen and pumps it back through your body. This is known as an “on-pump” procedure. The heart may be stopped temporarily before the graft is attached.
Attaching the graft
A small opening is made in the coronary artery below the blockage. If a vein from your leg or an artery from your arm is used for the bypass, one end of it is sewn onto this opening and the other end is sewn onto the aorta (the main artery from the heart to the body). If the chest artery is used, one end of the graft is sewn onto the opening. The other end is already attached to a branch of the aorta. In either case, the blood then uses the new vessel as a detour to bypass the blockage.
After the graft has been attached, a surgeon will restart your heart and take you off the heart-lung machine. Then the breastbone is closed with wires, and the incision in your skin is closed with stitches. The wires stay in your chest permanently.