Blockages can occur in the coronary arteries, decreasing the amount of blood flow to the heart muscle. The most common cause of blockages is fatty deposits (atherosclerosis) accumulating in the walls of the coronary arteries. This accumulation of fatty deposits is thought to be influenced by numerous risk factors that include:

As deposits continue to build within the arterial wall, the internal diameter of the vessel decreases, blockage results, and the blood supply to the heart muscle is jeopardized. This often results in chest pain known as ANGINA. Anginal pain is usually relieved by nitroglycerine and rest. If blood flow through a coronary artery becomes severely reduced, a portion of the heart muscle becomes damaged and may die-- known as a myocardial Infarction (MI) or heart attack. MI's are felt to be a consequence of blood clot formation (plaque rupture and thrombosis) in a coronary artery.

Surgical reconstruction of the blocked arteries began in the late 1960's and has proven to be remarkably successful. The operation we call Coronary Artery Bypass Grafting (CABG or "cabbage") is the foundation of surgical management. The goal of this operation is to restore the blood supply to the heart muscle by creating a new route (bypass) for the blood to flow around the blockages. CABG is not only the most common operation performed on the human heart, it is currently the most common procedure of any kind in the USA. Last year, over 200,000 coronary bypass operations were performed nationwide. Coronary Artery Bypass Grafting doesn't remove the obstructing blockages in the arteries. The procedure "reroutes" the flow of blood by using a "detour" pathway. Typically, the blockages occur in the first centimeter or two of the major branches feeding the heart. The smaller branches are usually not involved until very late life. Thus, it is possible to hook a new source of blood into the artery just beyond the last major blockage. Blood flows into the artery through a different path (such as a vein bypass graft) and reaches the heart muscle tissue where it is needed. The heart doesn't care how the blood gets there, as long as it gets what it needs during times of peak demand. Once the volume and pressure of blood flow is restored, the symptoms of exertional chest discomfort are relieved. The most common material used to build this new pathway is a vein from the lower extremity. In each of us, there is a long straight vein called the greater saphenous vein which runs from just inside the ankle bone up to the groin. This vein is just one of a large series of veins in the lower extremity. However, the Greater Saphenous Vein is the right size, shape, and length for use as a bypass conduit. The other major vessel used as a bypass graft is the left internal mammary artery (LIMA). Recent studies have shown that the internal mammary artery  is more resistant to atherosclerotic deposition than even the native coronary arteries. This vessel courses alongside the undersurface of the breastbone (sternum). By detaching the lower end of the LIMA, the vessel can be transplanted to the surface of the heart. Regardless of which conduit is used for the bypass, the main advantage offered by this surgical approach is the restoration of blood supply to the heart. The vein or mammary artery provide a new and unobstructed route for blood flow. When the surgeon connects the bypass to the native coronary artery beyond the obstruction, blood has a new path in which to flow into the blood vessel. Then when the heart demands more blood flow, it can be supplied via the bypass graft. It is important for the surgeon to provide a bypass for each major branch that is obstructed. In that way, the whole heart will have more blood supply, and the chest pains (angina) will be relieved.

In some patients, alternative treatment of coronary artery disease includes medical therapy with specific medication or non-surgical treatment such as balloon angioplasty , laser angioplasty, stents or atherectomy (plaque removal). Your physician (cardiologist) will help decide which treatment is best for you.

A conventional coronary artery bypass grafting operation is typically performed through an incision, called a median sternotomy, in the middle of the chest. Some surgeons may prefer to perform a smaller mini-sternotomy. The patient's heart is stopped, or "arrested" and she or he is placed on circulatory support. The circulatory support system (called cardiopulmonary bypass, or the heart lung machine) works in place of the patient's heart and lungs, providing blood flow to the whole body. As blood enters the cardiopulmonary bypass system, it exchanges carbon dioxide for oxygen (just as the lungs would), with the tubing functioning as the patient's veins and arteries. The blood is also filtered, and it is cooled or heated to keep the patient at a proper temperature. Two major advances in open heart surgery include "off pump coronary bypass" and "minimally invasive coronary artery bypass." Recent clinical studies suggest that there may be benefits to beating heart surgery, such as less blood trauma and need for transfusion, decreased risk of adverse events (such as stroke), and usually a return to normal activities more rapidly. One of the greatest challenges in beating heart CABG surgery is the difficulty of suturing or "sewing" on a beating heart. If the surgeon chooses to operate on a beating heart, a "stabilization" system is used to steady only the portion of the heart where the surgeon is operating. A stabilization system makes it possible for the surgeon to carefully work on the patient's beating heart, avoiding the need for the heart-lung machine. The goal of minimally invasive coronary bypass  is to avoid using the heart-lung machine. This operation  is performed while your heart is still beating and is intended for use when only one or two arteries will be bypassed. The minimally invasive procedure uses a combination of small holes or "ports" in your chest and a small incision made directly over the coronary artery to be bypassed. The cardiac surgeon usually detaches the internal mammary artery from inside the chest wall and re-attaches it to the blocked coronary artery. The surgeon views and performs the attachment directly, so the artery to be bypassed must be right under the incision.

After a bypass operation, patients usually remain in the hospital four to seven days. Following discharge, they are often advised to reduce their consumption of fat and cholesterol. They may also be advised to walk or do other physical activity to help them regain their strength. Doctors also often recommend following a home routine of increasing activity - doing light housework, going out, visiting friends, climbing stairs. The goal is to help a patient return to a normal, active lifestyle. Most people who have sedentary office jobs can return to work in four to six weeks. Those who have physically demanding jobs may have to wait longer. Your physician will advise you when you can return to work.