Heart-lung machines are also known as cardiopulmonary bypass machines. During a coronary artery bypass graft (CABG) surgery, the narrowed area or blocked side of the coronary artery is removed and grafted or attached to a blood vessel taken from the chest, leg, or arm. The heart-lung machine supports the patient during the CABG procedure while the heart is temporarily stopped by the physician. CABG is an open-heart surgery that is conducted for 4-6 hours.