In 2004, in the United States alone, nearly 427,000 coronary artery bypass graft surgeries (CABG) were performed in response to coronary artery disease (CAD). It was the most common major operation or heart surgery performed during that year.

Coronary artery disease (CAD) occurs when atherosclerotic plaque, primarily made of cholesterol, builds up in the arteries that supply oxygen and nutrients to the heart causing narrowing. Plaque buildup occurs more frequently among individuals who smoke, have high blood pressure, elevated cholesterol, and diabetes. Arteries that are more than 50 to 70 percent blocked are unable to provide adequate oxygen supply to the heart. Patients experience angina when the blood supply cannot keep up with the oxygen demand. Acute myocardial infarction (heart attack) may be imminent if a procedure is not performed to prevent a blood clot from forming in the area of the plaque causing blockage.

Coronary artery bypass graft heart surgery relieves angina in patients who are not good candidates for angioplasty (PTCA) and who have failed other medical therapies. CABG heart surgery creates a bypass around narrowed and blocked arteries. The bypass process allows more sufficient blood flow to deliver oxygen and nutrients to the heart muscle.

CABG heart surgery has been proven to improve long-term survival in patients with significant narrowing of the left main coronary artery. It also improves the life-span of those individuals with multiple narrow arteries and decreased functionality of the pumping mechanism of the heart.

A cardiac surgeon typically performs the surgery. An incision is made down the middle of the chest. Next, the breastbone or sternum is sawed through to allow the physician access to the heart muscle. This process is called a median sternotomy.

Cardioplegia is the process where a preservative solution is injected into the arteries and the heart is then cooled with iced salt water. This process minimizes damage caused by reduced blood flow during surgery.

The next step is establishing a cardiopulmonary bypass. In order to channel venous blood out of the body, plastic tubes are placed in the right atrium. The blood passes through plastic sheeting (membrane oxygenator) in the heart lung machine. The oxygenated blood returns to the body and the aorta is clamped off during the surgery. This process allows the surgeon to connect the bypass to the aorta in a bloodless field.

After 7 to 10 days sutures are removed from the chest and the leg, if a saphenous vein is used. Then, the patient is discharged. The patient is typically advised to wear elastic support stockings for six to eight weeks after the surgery until the swelling subsides. Healing of the breastbone may also take about 6 weeks. During this period, patients are advised not to lift more than 10 pounds.
Rehabilitation consists of a 12 week program. The patient exercises 1 hour per day, three times per week.

The mortality rate related to CABG is 3 to 4 per cent. One potential risk of the CABG heart surgery is that the patient may die of a heart attack during or shortly after the surgery. Chest infections and lung complications increase with the second surgery. One to two percent experience stroke. Mortality complications increase with age, poor heart muscle function, diabetes, chronic lung disease, and chronic kidney failure.

Women typically develop Coronary Heart Disease 10 years later than men because they are protected by the hormones produced during menstruation years. Mortality rates are higher in women than men, because it typically occurs when they are older. Women also have smaller arteries which make CABG heart surgery more difficult and prolonged.