If you have coronary artery disease (CAD), the arteries that supply blood and oxygen to the heart muscle become hardened and narrowed. If lifestyle changes and medicines don't help, your doctor may recommend coronary artery bypass surgery.
The surgery uses a piece of a vein from the leg or artery from the chest or wrist. The surgeon attaches this to the coronary artery above and below the narrowed area or blockage. This allows blood to bypass the blockage. Some people need more than one bypass.
You may need bypass surgery for various reasons. Another procedure for CAD, angioplasty, may not have widened the artery enough. In some cases, the angioplasty tube can't reach the blockage.
A bypass also can close again. This happens in more than 10 percent of bypass surgeries, usually after 10 or more years.
WHAT IS CORONARY ARTERY BYPASS GRAFTING (CABG)?
Coronary artery bypass grafting or "CABG" (often pronounced "cabbage") is the most commonly performed "open heart" operation in the United States. Cardiothoracic surgeons perform the procedure to bypass blockages or obstructions of the coronary arteries. The coronary arteries are the blood vessels that supply the heart with oxygen and nutrients. The heart relies on these fuels as it works constantly to pump blood through the body. The heart never rests like the other muscles in the body, and it demands a constant supply of fuel day and night. The term ischemic heart disease refers to this condition, when the heart does not get these fuels. When the heart is sufficiently ischemic (when the shortage of fuel is critical enough), the muscle begins to die. This is a "heart attack" or myocardial infarction.
WHAT CAN HAPPEN WHEN BLOCKAGES OCCUR IN THE BLOOD VESSELS LEADING TO THE HEART?
When there are blockages of the arteries to the heart, an individual may experience chest pain or angina pectoris, or ultimately even a heart attack or myocardial infarction. In some cases, particularly in individuals with diabetes mellitus, angina may be absent or infarctions "silent." A heart attack may be the first sign of coronary artery disease in many patients, and an electrocardiogram or EKG may be normal - even in the presence of coronary artery disease - if you have not yet had a heart attack.
You or your doctor may be suspicious of coronary artery disease if you have suggestive symptoms, multiple risk factors, and/or a strong family history of coronary artery disease. Risk factors include male sex, high blood cholesterol, diabetes mellitus, high blood pressure (hypertension), and cigarette smoking. The presence of coronary artery disease is most often confirmed by a noninvasive stress test or by cardiac catheterization. A stress test is performed on a treadmill with monitoring by electrocardiogram or echocardiography. It can often be performed as an outpatient. A cardiac catheterization study is an invasive test in which a small tube or catheter is passed through the artery in the groin or arm to the heart, and contrast medium or "dye" is injected into the coronary arteries. X-ray pictures are taken which can show the obstructions present.
Once coronary artery disease is diagnosed, there are a number of treatment options including medicines, angioplasty, and surgery.
WHAT ARE THE INDICATIONS FOR SURGERY?
The indications for CABG were first defined by the results of the Coronary Artery Surgery Study or CASS. The study was performed by cardiothoracic surgeons and cardiologists in the early days of bypass surgery. It showed a survival advantage for patients undergoing surgery who had disease of the left main coronary artery and those with disease of all three major coronary arteries and abnormal function of the main pumping chamber of the heart, the left ventricle. CABG may also be indicated in other specific circumstances, or when an individual patient is experiencing severe angina pectoris that cannot be controlled with medicines alone. The most important thing to keep in mind is that coronary artery disease is complex and every patient's specific situation is different. You should therefore discuss your circumstances with your doctor.
HOW IS THIS OPERATION PERFORMED?
Coronary Artery Bypass Grafting is a procedure performed exclusively by cardiothoracic surgeons. The traditional technique involves an incision down the front of the chest through the breastbone or sternum. This incision is called a median sternotomy. Through this incision the surgeon can see the heart and the aorta. The procedure as traditionally performed requires that the patient be connected to the heart lung machine while the bypasses are being performed. The heart can then be stopped using a special mixture of chemicals called cardioplegia. After the bypasses have been performed the patient is taken off of the machine and their own heart takes over once again.
