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
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.
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
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.
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 percutaneous coronary intervention (PCI), commonly known as 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.
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 (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.
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 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.
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.
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.
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.
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 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.
Recovery in the Hospital
After surgery, you'll typically spend 1 or 2 days in an intensive care unit (ICU). Your heart rate, blood pressure, and oxygen levels will be checked regularly during this time.
An intravenous line (IV) will likely be inserted into a vein in your arm. Through the IV line, you may get medicines to control blood circulation and blood pressure. You also will likely have a tube in your bladder to drain urine and a tube to drain fluid from your chest.
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 may recommend that you wear compression stockings on your legs as well. These stockings are tight at the ankle and become looser as they go up the leg. This creates gentle pressure up the leg. The pressure 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 an artery or vein was removed for grafting.
After you leave the ICU, you'll be moved to a less intensive care area of the hospital for 3 to 5 days before going home.
Recovery at Home
Your doctor will give you specific instructions for recovering at home, especially concerning:
- 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 also may get instructions on how to deal with common side effects from surgery. Side effects often go away within 4 to 6 weeks after surgery, but may include:
- Discomfort or itching from healing incisions
- Swelling of the area where an artery or vein was 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
- Chest pain around the site of the chest bone incision (more frequent with traditional CABG)
Full recovery from traditional CABG may take 6 to 12 weeks or more. Less recovery time is needed for nontraditional CABG.
Your doctor will tell you when you can start physical activity again. It varies from person to person, but there are some typical timeframes. Most people can resume sexual activity within about 4 weeks and driving after 3 to 8 weeks.
Returning to work after 6 weeks is common unless your job involves specific and demanding physical activity. Some people may need to find less physically demanding types of work or work a reduced schedule at first.
Care after surgery may include periodic checkups with doctors. During these visits, tests may be done to see how your heart is working. Tests may include EKG (electrocardiogram), stress testing, echocardiography, and cardiac CT.
CABG is not a cure for coronary heart disease (CHD). You and your doctor may develop a treatment plan that includes lifestyle changes to help you stay healthy and reduce the chance of CHD getting worse.
Lifestyle changes may include making changes to your diet, quitting smoking, doing physical activity regularly, and lowering and managing stress.
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.
Rehab programs include exercise training, education on heart healthy living, and counseling to reduce stress and help you return to an active life. Doctors supervise these programs, which may be offered in hospitals and other community facilities. Talk to your doctor about whether cardiac rehab might benefit you.
Taking medicines as prescribed also is an important part of care after surgery. Your doctor may prescribe medicines to manage pain during recovery; lower cholesterol and blood pressure; reduce the risk of blood clots forming; manage diabetes; or treat depression.
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
- 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.).