During a coronary artery bypass graft (CABG), the chest is opened to visualize the heart (A). A heart-lung machine takes over the function of the heart during the procedure. A portion of the saphenous vein of the leg is removed (B). This vessel is used to bypass a blockage of the coronary artery. It is attached from the aorta past the point of blockage (C). Another option is to bypass a blockage with the mammary artery (D). The bypass increases blood flow to the area served by the coronary artery (E). (Illustration by Argosy.)