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What Is Coronary Artery Bypass Grafting?

Coronary artery bypass grafting (CABG) is a type of surgery that improves blood flow to the heart. Surgeons use CABG to treat people who have severe coronary heart disease (CHD).

CHD is a disease in which a waxy substance called plaque (plak) builds up inside the coronary arteries. These arteries supply oxygen-rich blood to your heart.

Over time, plaque can harden or rupture (break open). Hardened plaque narrows the coronary arteries and reduces the flow of oxygen-rich blood to the heart. This can cause chest pain or discomfort called angina (an-JI-nuh or AN-juh-nuh).

If the plaque ruptures, a blood clot can form on its surface. A large blood clot can mostly or completely block blood flow through a coronary artery. This is the most common cause of a heart attack. Over time, ruptured plaque also hardens and narrows the coronary arteries.

CABG is one treatment for CHD. During CABG, a healthy artery or vein from the body is connected, or grafted, to the blocked coronary artery. The grafted artery or vein bypasses (that is, goes around) the blocked portion of the coronary artery. This creates a new path for oxygen-rich blood to flow to the heart muscle.

Surgeons can bypass multiple coronary arteries during one surgery.

Coronary Artery Bypass Grafting

Figure A shows the location of the heart. Figure B shows how vein and artery bypass grafts are attached to the heart.

Figure A shows the location of the heart. Figure B shows how vein and artery bypass grafts are attached to the heart.

Overview

CABG is the most common type of open-heart surgery in the United States. Doctors called cardiothoracic (KAR-de-o-tho-RAS-ik) surgeons do this surgery.

However, CABG isn't the only treatment for CHD. Other treatment options include lifestyle changes, medicines, and a procedure called coronary angioplasty (AN-jee-oh-plas-tee).

Angioplasty is a nonsurgical procedure that opens blocked or narrow coronary arteries. During angioplasty, a stent might be placed in a coronary artery to help keep it open. A stent is a small mesh tube that supports the inner artery wall.

CABG or angioplasty may be options if you have severe blockages in your large coronary arteries, especially if your heart's pumping action has already grown weak.

CABG also may be an option if you have blockages in the heart that can't be treated with angioplasty. In this situation, CABG may work better than other types of treatment.

The goals of CABG may include:

  • Improving your quality of life and reducing angina and other CHD symptoms
  • Allowing you to resume a more active lifestyle
  • Improving the pumping action of your heart if it has been damaged by a heart attack
  • Lowering the risk of a heart attack (in some patients, such as those who have diabetes)
  • Improving your chance of survival

Outlook

The results of CABG usually are excellent. The surgery improves or completely relieves angina symptoms in most patients. Although symptoms can recur, many people remain symptom-free for as long as 10 to 15 years. CABG also may lower your risk of having a heart attack and help you live longer.

You may need repeat surgery if blockages form in the grafted arteries or veins or in arteries that weren't blocked before. Taking medicines and making lifestyle changes as your doctor recommends can lower the risk of a graft becoming blocked.




Types of Coronary Artery Bypass Grafting

There are several types of coronary artery bypass grafting (CABG). Your doctor will recommend the best option for you based on your needs.

Traditional Coronary Artery Bypass Grafting

Traditional CABG is used when at least one major artery needs to be bypassed. During the surgery, the chest bone is opened to access the heart.

Medicines are given to stop the heart; a heart-lung bypass machine keeps blood and oxygen moving throughout the body during surgery. This allows the surgeon to operate on a still heart.

After surgery, blood flow to the heart is restored. Usually, the heart starts beating again on its own. Sometimes mild electric shocks are used to restart the heart.

Off-Pump Coronary Artery Bypass Grafting

This type of CABG is similar to traditional CABG because the chest bone is opened to access the heart. However, the heart isn't stopped, and a heart-lung bypass machine isn't used. Off-pump CABG sometimes is called beating heart bypass grafting.

Minimally Invasive Direct Coronary Artery Bypass Grafting

This type of surgery differs from traditional CABG because the chest bone isn't opened to reach the heart. Instead, several small cuts are made on the left side of the chest between the ribs. This type of surgery mainly is used to bypass blood vessels at the front of the heart.

Minimally invasive bypass grafting is a fairly new procedure. It isn't right for everyone, especially if more than one or two coronary arteries need to be bypassed.




Other Names for Coronary Artery Bypass Grafting

  • Bypass surgery
  • Coronary artery bypass surgery
  • Heart bypass surgery



Who Needs Coronary Artery Bypass Grafting?

Coronary artery bypass grafting (CABG) is used to treat people who have severe coronary heart disease (CHD) that could lead to a heart attack. CABG also might be used during or after a heart attack to treat blocked arteries.

Your doctor may recommend CABG if other treatments, such as lifestyle changes or medicines, haven't worked. He or she also may recommend CABG if you have severe blockages in your large coronary (heart) arteries, especially if your heart's pumping action has already grown weak.

CABG also might be a treatment option if you have blockages in your coronary arteries that can't be treated with angioplasty.

Your doctor will decide whether you're a candidate for CABG based on factors such as:

  • The presence and severity of CHD symptoms
  • The severity and location of blockages in your coronary arteries
  • Your response to other treatments
  • Your quality of life
  • Any other medical problems you have

Physical Exam and Diagnostic Tests

To find out whether you're a candidate for CABG, your doctor will give you a physical exam. He or she will check your heart, lungs, and pulse.

Your doctor also may ask you about any symptoms you have, such as chest pain or shortness of breath. He or she will want to know how often and for how long your symptoms occur, as well as how severe they are.

Your doctor will recommend tests to find out which arteries are clogged, how much they're clogged, and whether you have any heart damage.

EKG (Electrocardiogram)

An EKG is a simple test that detects and records your heart's electrical activity. The test shows how fast the heart is beating and its rhythm (steady or irregular). An EKG also records the strength and timing of electrical signals as they pass through each part of the heart.

An EKG can show signs of heart damage due to CHD and signs of a previous or current heart attack.

Echocardiography

Echocardiography (echo) uses sound waves to create a moving picture of your heart. The test shows the size and shape of your heart and how well your heart chambers and valves are working.

Echo also can show areas of poor blood flow to the heart, areas of heart muscle that aren't contracting normally, and previous injury to the heart muscle caused by poor blood flow.

There are several types of echo, including stress echo. This test is done both before and after a stress test. A stress echo usually is done to find out whether you have decreased blood flow to your heart, a sign of CHD.

Stress Test

Some heart problems are easier to diagnose when your heart is working hard and beating fast.

During stress testing, you exercise to make your heart work hard and beat fast while heart tests are done. If you can't exercise, you may be given medicine to raise your heart rate.

The heart tests done during stress testing may include nuclear heart scanning, echo, and positron emission tomography (PET) scanning of the heart.

Coronary Angiography and Cardiac Catheterization

Coronary angiography (an-jee-OG-rah-fee) is a test that uses dye and special x rays to show the insides of your coronary arteries.

To get the dye into your coronary arteries, your doctor will use a procedure called cardiac catheterization (KATH-eh-ter-ih-ZA-shun).

A thin, flexible tube called a catheter is put into a blood vessel in your arm, groin (upper thigh), or neck. The tube is threaded into your coronary arteries, and the dye is released into your bloodstream.

Special x rays are taken while the dye is flowing through the coronary arteries. The dye lets your doctor study blood flow through the heart and blood vessels. This helps your doctor find blockages that can cause a heart attack.

Other Considerations

When deciding whether you're a candidate for CABG, your doctor also will consider your:

  • History and past treatment of heart disease, including surgeries, procedures, and medicines
  • History of other diseases and conditions
  • Age and general health
  • Family history of CHD, heart attack, or other heart diseases

Your doctor may recommend medicines and other medical procedures before CABG. For example, he or she may prescribe medicines to lower your cholesterol and blood pressure and improve blood flow through your coronary arteries.

Angioplasty also might be tried. During this procedure, a thin, flexible tube with a balloon at its tip is threaded through a blood vessel to the narrow or blocked coronary artery.

Once in place, the balloon is inflated, pushing the plaque against the artery wall. This creates a wider path for blood to flow to the heart.

Sometimes a stent is placed in the artery during angioplasty. A stent is a small mesh tube that supports the inner artery wall.




What To Expect Before Coronary Artery Bypass Grafting

You may have tests to prepare you for coronary artery bypass grafting (CABG). For example, you may have blood tests, an EKG (electrocardiogram), echocardiography, a chest x ray, cardiac catheterization, and coronary angiography.

Your doctor will tell you how to prepare for CABG surgery. He or she will advise you about what you can eat or drink, which medicines to take, and which activities to stop (such as smoking). You'll likely be admitted to the hospital on the same day as the surgery.

If tests for coronary heart disease show that you have severe blockages in your coronary (heart) arteries, your doctor may admit you to the hospital right away. You may have CABG that day or the day after.




What To Expect During Coronary Artery Bypass Grafting

Coronary artery bypass grafting (CABG) requires a team of experts. A cardiothoracic surgeon will do the surgery with support from an anesthesiologist, perfusionist (heart-lung bypass machine specialist), other surgeons, and nurses.

There are several types of CABG. They range from traditional surgery to newer, less-invasive methods.

Traditional Coronary Artery Bypass Grafting

This type of surgery usually lasts 3–6 hours, depending on the number of arteries being bypassed. Many steps take place during traditional CABG.

You'll be under general anesthesia (AN-es-THEE-ze-ah) for the surgery. The term "anesthesia" refers to a loss of feeling and awareness. General anesthesia temporarily puts you to sleep.

During the surgery, the anesthesiologist will check your heartbeat, blood pressure, oxygen levels, and breathing. A breathing tube will be placed in your lungs through your throat. The tube will connect to a ventilator (a machine that supports breathing).

The surgeon will make an incision (cut) down the center of your chest. He or she will cut your chest bone and open your rib cage to reach your heart.

You'll receive medicines to stop your heart. This allows the surgeon to operate on your heart while it's not beating. You'll also receive medicines to protect your heart function during the time that it's not beating.

A heart-lung bypass machine will keep oxygen-rich blood moving throughout your body during the surgery. For more information about this machine, including an illustration, go to the Health Topics Heart Surgery article.

The surgeon will take an artery or vein from your body—for example, from your chest or leg—to use as the bypass graft. For surgeries with several bypasses, both artery and vein grafts are commonly used.

  • Artery grafts. These grafts are much less likely than vein grafts to become blocked over time. The left internal mammary artery most often is used for an artery graft. This artery is located inside the chest, close to the heart. Arteries from the arm or other places in the body also are used.
  • Vein grafts. Although veins are commonly used as grafts, they're more likely than artery grafts to become blocked over time. The saphenous vein—a long vein running along the inner side of the leg—typically is used.

When the surgeon finishes the grafting, he or she will restore blood flow to your heart. Usually, the heart starts beating again on its own. Sometimes mild electric shocks are used to restart the heart.

You'll be disconnected from the heart-lung bypass machine. Then, tubes will be inserted into your chest to drain fluid.

The surgeon will use wire to close your chest bone (much like how a broken bone is repaired). The wire will stay in your body permanently. After your chest bone heals, it will be as strong as it was before the surgery.

Stitches or staples will be used to close the skin incision. The breathing tube will be removed when you're able to breathe without it.

Nontraditional Coronary Artery Bypass Grafting

Nontraditional CABG includes off-pump CABG and minimally invasive CABG.

Off-Pump Coronary Artery Bypass Grafting

Surgeons can use off-pump CABG to bypass any of the coronary (heart) arteries. Off-pump CABG is similar to traditional CABG because the chest bone is opened to access the heart.

However, the heart isn't stopped and a heart-lung-bypass machine isn't used. Instead, the surgeon steadies the heart with a mechanical device.

Off-pump CABG sometimes is called beating heart bypass grafting.

Minimally Invasive Direct Coronary Artery Bypass Grafting

There are several types of minimally invasive direct coronary artery bypass (MIDCAB) grafting. These types of surgery differ from traditional bypass surgery because the chest bone isn't opened to reach the heart. Also, a heart-lung bypass machine isn't always used for these procedures.

MIDCAB procedure. This type of surgery mainly is used to bypass blood vessels at the front of the heart. Small incisions are made between your ribs on the left side of your chest, directly over the artery that needs to be bypassed.

The incisions usually are about 3 inches long. (The incision made in traditional CABG is at least 6 to 8 inches long.) The left internal mammary artery most often is used for the graft in this procedure. A heart-lung bypass machine isn't used during MIDCAB grafting.

Port-access coronary artery bypass procedure. The surgeon does this procedure through small incisions (ports) made in your chest. Artery or vein grafts are used. A heart-lung bypass machine is used during this procedure.

Robot-assisted technique. This type of procedure allows for even smaller, keyhole-sized incisions. A small video camera is inserted in one incision to show the heart, while the surgeon uses remote-controlled surgical instruments to do the surgery. A heart-lung bypass machine sometimes is used during this procedure.




What To Expect After Coronary Artery Bypass Grafting

Recovery in the Hospital

After surgery, you'll typically spend 1 or 2 days in an intensive care unit (ICU). Your health care team will check your heart rate, blood pressure, and oxygen levels regularly during this time.

An intravenous (IV) line will likely be inserted into a vein in your arm. Through the IV line, you may get medicines to control blood flow and blood pressure. You also will likely have a tube in your bladder to drain urine and a tube in your chest to drain fluid.

You may receive oxygen therapy (oxygen given through nasal prongs or a mask) and a temporary pacemaker while in the ICU. A pacemaker is a small device that's placed in the chest or abdomen to help control abnormal heart rhythms.

Your doctor also might recommend that you wear compression stockings on your legs. These stockings are tight at the ankle and become looser as they go up the legs. This creates gentle pressure that keeps blood from pooling and clotting.

While in the ICU, you'll also have bandages on your chest incision (cut) and on the areas where arteries or veins were removed for grafting.

After you leave the ICU, you'll be moved to a less intensive care area of the hospital for 3–5 days before going home.

Recovery at Home

Your doctor will give you instructions for recovering at home, such as:

  • How to care for your healing incisions
  • How to recognize signs of infection or other complications
  • When to call the doctor right away
  • When to make followup appointments

You'll also learn how to deal with common side effects from surgery. Side effects often go away within 4–6 weeks after surgery, but may include:

  • Discomfort or itching from healing incisions
  • Swelling of the area where arteries or veins were removed for grafting
  • Muscle pain or tightness in the shoulders and upper back
  • Fatigue (tiredness), mood swings, or depression
  • Problems sleeping or loss of appetite
  • Constipation
  • Chest pain at the site of the chest bone incision (more frequent with traditional CABG)

Full recovery from traditional CABG may take 6–12 weeks or more. Nontraditional CABG doesn't require as much recovery time.

Your doctor will tell you when you can become active again. It varies from person to person, but there are some typical timeframes.

Often, people can resume sexual activity and return to work after about 6 weeks. Some people may need to find less physically demanding types of work or work a reduced schedule at first.

Talk with your doctor about when you can resume activity, including sexual activity, working, and driving.

Ongoing Care

Care after surgery may include periodic checkups with doctors. During these visits, you may have tests to see how your heart is working. Tests may include an EKG (electrocardiogram), stress testing, echocardiography, and a cardiac CT scan.

CABG is not a cure for coronary heart disease (CHD). After the surgery, your doctor may recommend a treatment plan that includes lifestyle changes. Following the plan can help you stay healthy and lower the risk of CHD getting worse.

Lifestyle changes might include changing your diet, quitting smoking, being physically active, losing weight or maintaining a healthy weight, and reducing stress.

For more information about lifestyle changes, go to the National Heart, Lung, and Blood Institute's "Your Guide to Living Well With Heart Disease."

Your doctor also may refer you to cardiac rehabilitation (rehab). Cardiac rehab is a medically supervised program that helps improve the health and well-being of people who have heart problems.

Cardiac rehab includes exercise training, education on heart healthy living, and counseling to reduce stress and help you return to an active life. Your doctor can tell you where to find a cardiac rehab program near your home.

Taking medicines as prescribed also is important after CABG. Your doctor may prescribe medicines to manage pain during recovery, lower your cholesterol and blood pressure, reduce the risk of blood clots forming, manage diabetes, or treat depression.




What Are the Risks of Coronary Artery Bypass Grafting?

As with any type of surgery, coronary artery bypass grafting (CABG) has risks. The risks of CABG include:

  • Wound infection and bleeding
  • Reactions to anesthesia
  • Fever
  • Pain
  • Stroke, heart attack, or even death

Some patients have a fever associated with chest pain, irritability, and decreased appetite. This is due to inflammation involving the lung and heart sac.

This complication sometimes occurs after surgeries that involve cutting through the pericardium (the outer covering of the heart). The problem usually is mild, but some patients may develop fluid buildup around the heart that requires treatment.

Memory loss and other issues, such as problems concentrating or thinking clearly, might occur in some people.

These problems are more likely to affect older patients and women. These issues often improve within 6–12 months of surgery.

In general, the risk of complications is higher if CABG is done in an emergency situation (for example, during a heart attack). The risk also is higher if you have other diseases or conditions, such as diabetes, kidney disease, lung disease, or peripheral arterial disease (P.A.D.).




Clinical Trials

The National Heart, Lung, and Blood Institute (NHLBI) is strongly committed to supporting research aimed at preventing and treating heart, lung, and blood diseases and conditions and sleep disorders.

NHLBI-supported research has led to many advances in medical knowledge and care. For example, this research has helped look for better ways to treat heart problems using methods such as coronary artery bypass grafting (CABG).

The NHLBI continues to support research on CABG. For example, NHLBI-sponsored research includes studies that:

  • Compare CABG with angioplasty and stenting in patients who have diabetes and blockages in more than one coronary artery
  • Explore whether a valve procedure should be done at the same time as CABG in some patients who have coronary heart disease and heart valve defects
  • Examine whether using off-pump CABG, as opposed to traditional CABG, might reduce neurological side effects in patients

Much of this research depends on the willingness of volunteers to take part in clinical trials. Clinical trials test new ways to prevent, diagnose, or treat various diseases and conditions.

For example, new treatments for a disease or condition (such as medicines, medical devices, surgeries, or procedures) are tested in volunteers who have the illness. Testing shows whether a treatment is safe and effective in humans before it is made available for widespread use.

By taking part in a clinical trial, you may gain access to new treatments before they're widely available. You also will have the support of a team of health care providers, who will likely monitor your health closely. Even if you don't directly benefit from the results of a clinical trial, the information gathered can help others and add to scientific knowledge.

If you volunteer for a clinical trial, the research will be explained to you in detail. You'll learn about treatments and tests you may receive, and the benefits and risks they may pose. You'll also be given a chance to ask questions about the research. This process is called informed consent.

If you agree to take part in the trial, you'll be asked to sign an informed consent form. This form is not a contract. You have the right to withdraw from a study at any time, for any reason. Also, you have the right to learn about new risks or findings that emerge during the trial.

For more information about clinical trials related to CABG, talk with your doctor. You also can visit the following Web sites to learn more about clinical research and to search for clinical trials:




Links to Other Information About Coronary Artery Bypass Grafting

NHLBI Resources

Non-NHLBI Resources

Clinical Trials

 
February 23, 2012 Last Updated Icon

The NHLBI updates Health Topics articles on a biennial cycle based on a thorough review of research findings and new literature. The articles also are updated as needed if important new research is published. The date on each Health Topics article reflects when the content was originally posted or last revised.

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