Coronary Bypass Surgery is a type of heart surgery that bypasses a blocked artery to improve blood flow to the heart. In this surgery, the surgeon removes a healthy blood vessel from another part of the body, and connects it from the start of the blockage to the end of the blockage, providing a different route for the blood to flow. This new vessel allows blood to flow around the blocked area, and increases the amount of blood reaching the heart. In some cases, patients who have had this surgery in the past might develop blockages in the grafted blood vessels originally used in the first surgery. In this case, they will undergo the coronary bypass surgery again to adjust blood flow.