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Heart bypass surgery

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Illustrations

Heart, front view
Heart, front view
Posterior heart arteries
Posterior heart arteries
Anterior heart arteries
Anterior heart arteries
Atherosclerosis
Atherosclerosis
Heart bypass surgery - series
Heart bypass surgery - series

Alternative Names    Return to top

Bypass surgery - heart; CABG; Coronary artery bypass graft

Definition    Return to top

Heart bypass surgery is performed to route blood flow around clogged arteries supplying the heart.

Description    Return to top

Coronary arteries are the small blood vessels that supply the heart muscle with oxygen and nutrients. Fat and cholesterol can build up inside these small arteries. The arteries can gradually become clogged. This buildup of fat and cholesterol plaque is called atherosclerosis.

When one or more of the coronary arteries becomes partially or totally blocked, the heart does not get enough blood. This is called ischemic heart disease or coronary artery disease (CAD). It can cause chest pain (angina).

Sometimes CAD does not cause pain until the blood supply to the heart becomes critically low, and the muscle begins to die. The first symptom of CAD in this case may be a potentially deadly heart attack. Symptomless CAD is especially common in diabetics.

OVERVIEW OF THE PROCEDURE

Heart bypass surgery creates a detour or "bypass" around the blocked part of a coronary artery to restore the blood supply to the heart muscle. The surgery is commonly called Coronary Artery Bypass Graft, or CABG (pronounced "cabbage").

You will receive anesthesia and be completely free from pain. Then the heart surgeon makes a surgical cut in the middle of the chest and separates the breastbone.

Through this cut, the surgeon can see the heart and aorta (the main blood vessel leading from the heart to the rest of the body). After surgery, the breastbone will be rejoined with wire and the opening will be sewn closed.

ARTERY AND VEIN GRAFTS

If the saphenous vein in the leg is to be used for the bypass, an incision is made in the leg and the vein is removed. The vein is located on the inside of the leg. It runs from the ankle to the groin.

The saphenous vein normally does only about 10% of the work of circulating blood from the leg back to the heart. Therefore, it can be taken out without harming you or or the leg.

The internal mammary artery (IMA) can also be used as the graft. This has the advantage of staying open for many more years than the vein grafts, but there are some situations in which it cannot be used.

The left IMA, or LIMA, is an artery that runs next to the sternum on the inside of the chest wall. It can be disconnected from the chest wall without affecting the blood supply to the chest. It is commonly connected to the artery on the heart that supplies most of the muscle.

Other arteries are also now being used in bypass surgery. The most common of these is the radial artery. This is one of the two arteries that supply the hand with blood. It can usually be removed from the arm without affecting the blood supply to the hand.

TRADITIONAL APPROACH

In the traditional surgery, you are connected to the heart-lung machine, or bypass pump. This machine adds oxygen to the blood and circulates blood during the surgery. This is necessary because the heart muscle must be stopped before the graft can be done.

One end of the graft is stitched to an opening below the blockage in the coronary artery. If the grafted vessel is the saphenous vein or the radial artery, its other end is stitched to an opening made in the aorta. If the grafted vessel is the mammary artery, its other end is already connected to the aorta.

The entire surgery can take 4-6 hours. After the surgery, you will be taken to the Intensive Care Unit. For a few days after the surgery, you will be connected to monitors and tubes.

OTHER TECHNIQUES

Other surgical techniques for this procedure are being used more frequently. One popular method is to avoid the use of the heart-lung machine. This is called off-pump coronary artery bypass or OPCAB. This operation allows the bypass to be created while the heart is still beating.

The advantage is that use of the heart-lung machine can lead to some loss of memory and mental clarity. With OPCAB, that risk is reduced because the heart isn't stopped, and oxygen isn't added to the blood outside the body.

Another alternative is the use of smaller incisions that avoid splitting the breastbone. This is referred to as Minimally Invasive Direct Coronary Artery Bypass or MIDCAB.

Coronary bypass surgery can now be performed with the aid of a robot. This robot allows the surgeon to perform the operation without being in the same room as the patient.

Why the Procedure is Performed    Return to top

Coronary artery bypass surgery is a treatment option for ischemic heart disease (too little blood reaching the heart muscle). Coronary surgery is recommended for:

The earliest symptoms of ischemic heart disease include chest pain (angina) and shortness of breath. You may have no symptoms; mild, intermittent chest pain; or more pronounced and steady pain. Some people have CAD that is severe enough to make everyday activities difficult.

Symptoms that usually bring a person to a doctor are a feeling of heaviness, tightness, pain, burning, pressure, or squeezing. This is usually behind the breastbone, but sometimes it is also in the arms, neck, or jaw. Some people have heart attacks without ever having any of these symptoms first.

In cases where there are no symptoms, a doctor may suspect CAD and perform a stress test to determine if it is present. CAD is sometimes suspected if there is a family history of heart disease and a combination of other factors, including:

Because CAD varies so much from one person to another, the way it is diagnosed and treated will also vary. Heart bypass surgery is just one treatment.

Risks    Return to top

When considering the risks of CABG, it is important to remember that bypass surgery has been performed for more than 30 years. It is the most frequently performed major surgery in the United States. Cardiovascular surgeons have received extensive training in bypass techniques.

As with any surgery, your health before surgery is a major consideration in determining your risks. Health conditions that should be considered before surgery are:

Possible risks in having CABG are:

About a third of patients have "post-pericardiotomy syndrome" a few days to 6 months after surgery. The symptoms of this syndrome are fever and chest pain. It can be treated with medication.

The surgery site in the chest or the graft site (if the graft was from the leg or arm) can be itchy, sore, numb, or bruised.

Some people report memory loss and loss of mental clarity or "fuzzy thinking" after CABG.

As with all surgeries, there is a risk for heavy bleeding. In case you need a transfusion during or after surgery, ask your doctor about banking your own blood beforehand. You may also have family or friends with a compatible blood type donate blood for your surgery. The hospital, Red Cross, or local blood bank can provide family members and friends with necessary information about blood donation for your surgery.

There are general risks from anesthesia. These include reactions to medications and problems breathing.

Outlook (Prognosis)    Return to top

In most people who have heart bypass surgery, the grafts remain open and functioning for 10 to 15 years.

CABG will improve blood flow to the heart but NOT prevent the coronary blockage from returning. Lifestyle changes are necessary:

Recovery    Return to top

After the operation, you will spend 5 - 7 days in the hospital. You'll spend the first 2 hours in an intensive-care unit (ICU). In the ICU, heart function is monitored continuously.

You may need the temporary assistance of a breathing tube for a few hours after surgery. Two to three tubes in the chest drain fluid from around the heart and are usually removed 1 - 3 days after surgery.

A urinary catheter in the bladder drains urine until you are able to void on your own. Intravenous lines (IV) provide fluids and medications. Nurses watch the monitors and check vital signs (pulse, temperature, breathing) constantly.

When constant monitoring is no longer needed, usually within 12 - 24 hours, you will be moved to a regular or a transitional care unit. You can gradually resume activity. You may begin a cardiac rehabilitation program within a few days. The incision in the chest does not bother most people after the first 48 - 72 hours.

After surgery, it takes 4 - 6 weeks to start feeling better. During recovery it is normal to:

The full benefits from the operation may not be determined until 3 - 6 months after surgery. You may resume sexual activities 4 weeks after surgery. All activities that do not cause fatigue are permitted. Your doctor will help you determine the schedule for resuming normal activities.

References    Return to top

Hannan EL, Wu C, Walford G, Culliford AT, Gold JP, Smith CR, et al. Drug-eluting stents vs. coronary-artery bypass grafting in multivessel coronary disease. N Engl J Med. 2008;358:331-341.

Antman EM, Hand M, Armstrong PW, Bates ER, Green LA, Halasyamani LK, Hochman JS, et al. 2007 Focused Update of teh ACC/AHA 2004 Guidelines for the Management of Patients with ST-Elevation Myocardial Infarction: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation. 2008;117:296-329.

Update Date: 5/15/2008

Updated by: Robert A. Cowles, MD, Assistant Professor of Surgery, Columbia University College of Physicians and Surgeons, New York, NY. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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