General description of coronary artery bypass graft (CABG) surgery

What is coronary artery bypass graft (CABG) surgery?

Coronary artery bypass graft (CABG) surgery creates detours around diseased coronary arteries. This allows more blood to reach your heart. CABG surgery can help relieve chest pain and other symptoms of coronary artery disease (CAD).

What is the problem in CAD?

CAD is what happens when you have atherosclerosis (say "ath-er-oh-skler-OH-sis") in your coronary arteries. Your coronary arteries are blood vessels that supply blood to your heart muscle. Atherosclerosis is the medical term for a buildup of a hard, waxy substance called plaque (mostly cholesterol) inside your arteries. Over time, the buildup of plaque will start to narrow the space inside your arteries and limit the flow of oxygen-rich blood to your heart.

What you need to know

CAD is one of the most serious health problems in the United States. CABG surgery can treat the symptoms of CAD, but it can't cure CAD. Although CABG creates a new route for blood flow, with time atherosclerosis may develop in other coronary arteries and within the grafted artery itself.

What is CABG surgery?

CABG surgery creates a detour, or bypass, around your blocked artery. The surgeon creates a bypass using a healthy piece of blood vessel from another part of your body. Your surgeon will attach, or graft, this borrowed blood vessel both above and below the blocked section of your artery.

What is a bypass graft, and how does it fix the problem?

A bypass is an alternate route. During CABG surgery, your surgeon will create an alternate route for oxygen-rich blood to flow to your heart. Your surgeon does this by taking a piece of a blood vessel from somewhere else in your body. Your surgeon will then attach, or graft, this borrowed blood vessel both above and below the narrowed or blocked section of your diseased coronary artery. This graft will reroute blood, providing oxygen and other nutrients to your heart muscle.

Where does the borrowed blood vessel come from?

Your surgeon can remove, or harvest, a healthy piece of blood vessel from several places in your body. The saphenous veins along the inside of your legs, the radial artery in your forearm, and the internal mammary artery behind your left rib cage are preferred by surgeons because they are long, generally healthy, and easy to access. They come from areas of your body that have many blood vessels and that will be able to compensate well. The left internal mammary artery is popular with surgeons because it is already attached to the aorta on one end. So, only one end of the artery needs to be detached and then grafted to a coronary artery.

How many grafts are necessary?

Your doctor determines how many grafts you need based on how badly your coronary arteries are diseased and how many places in your arteries are blocked or significantly narrowed.

Your doctor evaluates your arteries using a test called a coronary angiogram, a special X-ray image of your heart that provides pictures of your blocked or narrowed arteries. A coronary angiogram is done as part of a cardiac catheterization before the day of your surgery to help your surgeon make a map of your arteries and decide which sections will need to be bypassed.

You may have heard of "double bypass surgery" or "quadruple bypass surgery." The number refers to how many bypasses the surgeon grafted. For example, quadruple bypass surgery means that four different bypasses were grafted onto your coronary arteries during the procedure.

Not a cure

Keep in mind that CABG surgery does not cure CAD. It can't get rid of the plaque in your arteries. That means your CAD will not go away after CABG surgery. If you don't treat your CAD, other arteries can get narrowed or blocked. Even the bypass blood vessels can become diseased.

What happens during CABG surgery?

There are eight steps in CABG surgery:

• You will be put to sleep with general anesthesia.
• Your surgeon will cut open your chest bone (sternum) to reach your heart and arteries.
• Your surgeon will remove a piece of healthy blood vessel from your arm, leg, or chest.
• You may be connected to a machine that does the jobs of your heart and lungs (heart-lung bypass machine). This machine allows your surgeon to stop your heartbeat while he or she works on your arteries. Or you may not be connected to this machine and your surgeon will perform the surgery on your beating heart.
• Your surgeon will use the blood vessel from your arm, leg, or chest to create bypass grafts around the narrowed and blocked parts of your arteries.
• Your surgeon will restart your heart.
• Your surgeon will put your chest bone back together and sew up your chest.
• You will wake up when the anesthesia wears off.

What is it like to have CABG surgery?

CABG surgery is a long procedure that takes about 3 to 6 hours. After the surgery, you will probably have to stay in the hospital for several days. When you leave the hospital, you will have to recover at home for about 4 to 6 weeks. You may also need to make changes in your lifestyle. For example, eating a balanced diet and quitting smoking are excellent ways to improve your heart's health. Your recovery may also involve a cardiac rehabilitation program. This program helps you get your strength back and make lifestyle changes.

How effective is CABG surgery?

CABG surgery is considered successful when it increases blood flow to the heart. This helps prevent further damage to your heart because the muscle is no longer starved for oxygen and other nutrients. The procedure is also highly effective in treating chest pain (angina).

In some people CABG surgery has been shown to improve their chances of survival. However, in several studies CABG was not shown to significantly reduce the incidence of heart attack or the progression of CAD.¹ This is probably true because the surgery does not treat the underlying cause of CAD: atherosclerosis.

What are the risks of CABG surgery?

CABG surgery is an invasive procedure. Therefore, the possible risks include bleeding, infection, heart attack, kidney failure, stroke, and death. The chance of these complications depends on a person's individual factors such as age and other health problems. About 98% of people younger than age 65 with no other health problems have an uneventful recovery after CABG. But the risks of complications increase with age and the presence of other medical conditions or other heart damage.

Final thoughts

Atherosclerosis is caused by heredity and lifestyle choices and can be treated with changes in your lifestyle or prescription medications. Therefore, having CABG surgery does not mean that your CAD will go away or even get better.

After the surgery, CAD may redevelop in other coronary arteries, or the new pieces of artery used as bypasses can become diseased as well. CABG can help your chest pain but will help your CAD most if you follow your doctors' recommendations and make the appropriate lifestyle changes after your surgery.

Recommendations that will help slow the progression of atherosclerosis include:

• Stop smoking.
• Control your high blood pressure.
• Lower your cholesterol if it is high.
• Keep your blood sugar under control if you have diabetes.

Citations

1. Gersh BJ, et al. (2001). Coronary artery bypass surgery section of Chronic coronary artery disease. In E Braunwald et al., eds., Heart Disease: A Textbook of Cardiovascular Medicine, 6th ed., vol. 2, pp. 1302–1324. Philadelphia: W.B. Saunders.

Author:	Robin Parks, MS	Last Updated May 26, 2006
Medical Review:	Caroline S. Rhoads, MD - Internal Medicine Linda F. Hellstedt, MSN, RN - Cardiac Nursing Robert A. Kloner, MD, PhD - Cardiology Ruth Schneider, MPH, RD - Diet and Nutrition
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