Coronary Artery Bypass Grafting is an operation in which a blood vessel is taken from your chest, leg or forearm and grafted (attached) to your coronary artery to let blood “detour” past a narrowing or blockage in this artery. It is used to improve blood flow to your heart muscle, when blood flow is reduces due to coronary heart disease (CHD). CABG is a common and successful way to improve the health of people with CHD.