Bypass surgery is most often done as an open-heart surgery. The surgeon makes a vertical incision in the skin and muscle in the middle of the chest and then cuts through the breastbone (sternum).

The surgeon spreads the rib cage with a retractor to expose the heart and then cuts through the lining that protects the heart (pericardium).

To reroute blood flow around the diseased blood vessel, surgeons use a blood vessel taken from another part of your body. For example, the saphenous vein from the leg or an internal mammary artery from the chest may be used.

Regardless of which type of blood vessel is used, oxygen-rich blood from the aorta is rerouted around the narrowed or blocked section of the coronary artery to improve blood flow to the heart muscle.