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Coronary Artery Bypass Grafting

Also known as Heart Bypass Surgery
Coronary artery bypass grafting (CABG) is a procedure to improve poor blood flow to the heart. It may be needed when the arteries supplying blood to heart tissue, called coronary arteries, are narrowed or blocked. This surgery may lower the risk of serious complications for people who have obstructive coronary artery disease, a type of ischemic heart disease. CABG may also be used in an emergency, such as a severe heart attack.

CABG uses blood vessels from another part of the body and connects them to blood vessels above and below the narrowed artery, bypassing the narrowed or blocked coronary arteries. One or more blood vessels may be used, depending on the severity and number of blockages. The blood vessels are usually arteries from the arm or chest, or veins from the legs. Risks and possible complications may occur with this procedure. After CABG, your doctor may recommend medicines and heart-healthy lifestyle changes to further reduce your symptoms, treat your disease, and help prevent complications such as blood clots.

Explore this Health Topic to learn more about CABG, our role in research and clinical trials to improve health, and where to find more information.

Who May Benefit - Coronary Artery Bypass Grafting

People who have certain conditions may benefit from CABG, such as those who have obstructive coronary artery disease, a type of ischemic heart disease. Obstructive coronary arteries disease occurs when plaque builds up in the coronary arteries that supply the heart with oxygen-rich blood.

Your heart care team will work with you to decide if CABG is right for you. Your team includes your heart doctor, called a cardiologist, and a cardiothoracic surgeon, who specializes in heart, lung, and chest surgeries.

During an emergency, such as a heart attack or sudden cardiac arrest, CABG or another procedure may be performed with consent from a heart care team. If it is not an emergency, the team will evaluate your symptoms, medical history, the severity of your condition, your overall health, and how treatment will help you. The team will also consider your preferences after discussing the risks and benefits of CABG with you and your family.

Image of coronary artery disease before and after heart bypass surgery.
Image of coronary artery disease before and after heart bypass surgery. The image on the left shows the heart before CABG. The gray region shows decreased blood flow due to coronary artery disease. The image on the right shows two grafts after a CABG procedure. One graft, shown in blue, is a vein that was taken from the leg, and the other, shown in red, is an artery that came from the chest. For each graft, one side connects to a coronary artery and the other side connects to a large artery that supplies blood to parts of the heart. These grafts bypass the blocked arteries and restore blood flow to the heart. Medical Illustration Copyright © 2019 Nucleus Medical Media, All rights reserved.


The heart care team may recommend CABG to relieve symptoms and to improve your chance of living longer. Surgery is not always the best option for everyone. Depending on your overall health and other conditions, your care team may recommend an alternative procedure called percutaneous coronary intervention (PCI), which may include placing a stent. This procedure is also known as coronary angioplasty.

CABG may be recommended when you have:

  • A need for open-heart surgery for other reasons
  • Diabetes
  • Heart attack due to coronary artery disease that cannot be treated properly with PCI
  • Ischemic heart disease with angina that has not gone away with medicine, or with a history of sudden cardiac arrest related to heart arrhythmia
  • Multiple blocked coronary arteries or large amounts of plaque in the left main coronary artery that would be difficult to treat with PCI
  • Severe or advanced heart failure that affects your heart’s ability to pump blood

Before Surgery - Coronary Artery Bypass Grafting

Your doctor may use diagnostic tests or procedures before CABG to determine how serious your ischemic heart disease is and where the coronary arteries are narrowed. If you need CABG, talk to your doctor about how to prepare for the procedure.

Diagnostic tests and procedures
- Coronary Artery Bypass Grafting

Tests and procedures may include the following:

  • Electrocardiogram (ECG or EKG) to record the electrical activity of the heart. An EKG can show signs of heart damage.
  • Stress tests to measure how well your heart works during physical stress. The stress may be physical exercise, such as walking on a treadmill, or it may be a medicine given to have the same effect.
  • Echocardiogram to assess heart function. This includes whether the valves or pumping is abnormal.
  • Coronary angiography to see how blood flows through your arteries. It is performed along with cardiac catheterization. The angiogram shows how severe the disease is, which arteries are affected, and the location of the affected arteries.
  • CT angiography to take pictures of your blood vessels. This is an alternative to cardiac catheterization that uses an injection of dye in the arm along with computed tomography (CT) imaging. Because it does not involve threading a catheter into the heart as cardiac catheterization does, CT angiography may be safer for some patients.
  • Coronary calcium scan to get images of the calcium in the walls of your coronary arteries, which is linked to coronary artery disease. This test uses CT imaging.

Preparing for surgery
- Coronary Artery Bypass Grafting

CABG may be planned ahead of time, or it may be performed in an emergency situation, such as after a heart attack that leads to severe heart failure. If your surgery is scheduled, talk to your doctor about what to expect and how to prepare, such as:

  • Which medicines you should stop taking and when to stop. Ask about all the medicines you take, even if they are not prescription, as well as supplements.
  • Which medicines you should begin taking and when to start them.
  • How to bathe before surgery. You may be told to use a special soap to wash your body.
  • When to stop eating and drinking before surgery.
  • When to arrive at the hospital and where to go.
  • What to expect after surgery and during the recovery period.

Your doctor will also discuss treatment options with you, including the risks and possible complications during and after surgery. Ask your doctor any questions you have so you can make the best decision about your treatment.

Look for
- Coronary Artery Bypass Grafting

  • During Surgery will describe the steps of a typical CABG surgery.
  • After Surgery will explain what happens in the days after surgery and the risks of the surgical procedure.

During Surgery - Coronary Artery Bypass Grafting

During CABG, a surgical team will take one or more blood vessels from another part of your body and connect it to the blocked artery in your heart. CABG may be performed in one of three ways. In traditional CABG, the chest is cut open and a machine pumps your blood. In “off-pump” CABG, the chest is opened, but a machine for pumping blood is not used. With minimally invasive CABG methods, only small cuts are made in the chest, and a machine is not used.

Surgical team
- Coronary Artery Bypass Grafting

Your surgical team will include a cardiothoracic surgeon, who will work on your heart. An anesthesiologist will give you medicine to make you sleep before the surgery, connect you to a breathing machine, and monitor your vital signs throughout the procedure. A perfusionist will manage the heart-lung pump, and nurses and other surgeons may help throughout the surgery.

Traditional CABG surgery
- Coronary Artery Bypass Grafting

Traditional CABG is the most common type of CABG surgery. This surgery takes about three to six hours, depending on how many arteries need to be bypassed. Learn more about how to prepare before surgery.

You will be given an intravenous (IV) line for fluids and medicines that will make you sleep before the surgery. You will be connected to a ventilator to support your breathing. The surgeon makes a cut down the middle of the chest, through the breastbone. The bone is split and the rib cage separated so the surgeon can reach the heart.

You will receive medicines to temporarily stop your heart from beating. This makes it easier for the surgeon to connect the healthy blood vessels, called grafts, into the coronary arteries. This requires a heart-lung bypass machine, which adds oxygen to your blood and pumps it throughout your body during surgery while your heart is not beating.

Illustration demonstrating how a heart-lung bypass machine works during surgery.
How a heart-lung bypass machine works during surgery. The heart-lung bypass machine adds oxygen and pumps blood throughout the body while the heart is stopped during surgery. The blood supply is connected to the machine through tubes. First, blood that needs oxygen leaves the heart and goes into the machine, bypassing the lungs. Oxygen is added to the blood in the machine. Then the machine pumps the oxygen-rich blood to the rest of the body.

The surgeon will then take an artery or a veins from your leg, arm, stomach, or chest. The graft is connected to the blocked coronary artery. The new blood vessel bypasses the blocked portion to create a new path for blood flow to the heart muscle. The number of grafts depends on how many coronary arteries need to be bypassed.

When the grafting is finished, the surgeon will restart the heart and restore blood flow. The heart usually starts beating on its own, but sometimes mild shocks are used to start it. Surgeons will sew the breastbone back together with a wire.

Off-pump CABG
- Coronary Artery Bypass Grafting

Sometimes CABG can be done without stopping the heart and using a heart-lung bypass machine. This is called off-pump CABG because the heart-lung bypass machine, or pump, is not used. The heart is steadied with a mechanical device. It is more difficult for surgeons because the heart is beating, and surgeons do not have easy access to blood vessels. However, it may be safer for certain people, such as those who have a higher risk of complications from using a heart-lung bypass machine. These include older adults and people who have ventricular dysfunction, diabetes, kidney disease, and chronic lung disease. This type of surgery is also sometimes called beating-heart bypass grafting.

Minimally invasive CABG
- Coronary Artery Bypass Grafting

Sometimes, CABG surgery may not be done as open heart surgery. There are less-invasive methods, including:

  • Minimally invasive direct coronary artery bypass (MIDCAB). MIDCAB is a modified version of CABG where the chest bone is not cut open. Instead, the surgeon makes a smaller cut on the left side of the chest over the artery that needs to be bypassed and enters in between the ribs. It is also usually an off-pump procedure.
  • Robotic. Sometimes CABG surgery can be done using a robot to surgically place the graft. This is called robotic-assisted or robotic surgery. The surgeon controls the robot instead of doing the work by hand, and the machinery only needs small openings in the chest. A heart-lung bypass machine is sometimes used.
  • Hybrid. During a hybrid bypass surgery, the robotic bypass is done for one of the main arteries, but a stent is used for other blocked arteries. The stent is a rolled-up mesh tube-like structure that goes inside the blocked artery to hold it open. This procedure is typically used only if your doctor is unable to perform the traditional bypass procedure.

Look for
- Coronary Artery Bypass Grafting

  • After Surgery will explain what happens in the days after surgery and the risks of the surgical procedure.
  • Life After will discuss lifestyle changes, medicines, and possible long-term complications that may be part of life after surgery.

After Surgery - Coronary Artery Bypass Grafting

After CABG surgery, you will need time to recover. There are also potential complications from surgery.

Recovery in the hospital
- Coronary Artery Bypass Grafting

You will stay in the hospital for about one week. You may stay longer if you had other procedures done as well or if you have a complication. You will stay in an intensive care unit (ICU) for a day or two, where medical staff may do the following:

  • Apply bandages on your chest and wherever the graft was removed.
  • Attach tubes to drain fluid from your chest and urine from your bladder.
  • Connect you to an electrocardiogram (ECG) to monitor your heart rhythm.
  • Implant a temporary pacemaker, and, in some cases, an implantable cardioverter defibrillator (ICD), while you are recovering in the ICU.
  • Give you compression stockings to wear on your legs to help maintain proper blood flow and avoid venous thromboembolism.
  • Give you medicines. Some medicines you may take for only a short time, while others you may need to keep taking. These medicines may help with pain during recovery, prevent blood clots or irregular heart rhythms, control cholesterol and fats in the blood, and lower your risk of complications.
  • Give you oxygen therapy, which delivers oxygen into your nose through nasal prongs or a mask.
  • Monitor your vital signs, such as your heart rate, blood pressure, and oxygen levels.

Recovery at home
- Coronary Artery Bypass Grafting

After you leave the hospital, you will need to continue taking medicines. Some common side effects from surgery, which should go away in four to six weeks, include the following:

  • Chest pain around the site of the surgical cut
  • Constipation
  • Discomfort or itching from healing cuts
  • Fatigue, mood swings, or depression
  • Muscle pain or tightness in the shoulders and upper back
  • Problems sleeping or loss of appetite
  • Swelling of the area where an artery or vein was removed for grafting

After you leave the hospital, you will need about six to 12 weeks to recover completely. People who undergo minimally invasive CABG need less time to recover than for traditional CABG.

All surgeries have risks. The risk is generally higher for certain people, such as those who get CABG in an emergency situation, have plaque in other arteries throughout the body, or have other medical conditions, such as major heart failure, or lung or kidney disease. Potentially serious complications may include:

  • Arrhythmia, or irregular heartbeat. The most common type is called atrial fibrillation, which may occur after the surgery but usually goes away on its own.
  • Bleeding, which may require more surgery to control it
  • Confusion or problems thinking clearly, temporary memory loss, vision problems, and slurred speech can occur for a short time right after surgery. This is also known as postoperative cognitive decline (POCD). Delirium, or intense confusion, is rare. The exact cause of POCD is not known. Many factors, including the health of the patient before surgery, likely play a role.
  • Heart attack
  • Infection, which can occur where the surgical cut was made or inside the chest where the surgery was performed. This may require additional surgeries.
  • Kidney failure
  • Stroke

Look for
- Coronary Artery Bypass Grafting

  • Life After will discuss the lifestyle changes, medicines, and possible long-term complications that may be part of life after coronary artery bypass graft surgery.
  • Research for Your Health will explain how we are using current research and advancing research to improve coronary artery bypass grafting.
  • Participate in NHLBI Clinical Trials will discuss our open and enrolling clinical studies that are investigating the best use of coronary artery bypass grafting.

Life After - Coronary Artery Bypass Grafting

CABG is a treatment but not a cure for ischemic heart disease. It is important to work with your doctor after CABG to help you stay healthy. This may include taking medicines prescribed by your doctor, making healthy lifestyle changes, getting regular medical checkups, and participating in cardiac rehabilitation.

Take your medicines as directed
- Coronary Artery Bypass Grafting

Your doctor will likely discuss medicines with you shortly after your surgery. Some of them are important to start right away. You may need to take them for up to one year or even continuously throughout your life. These medicines may include:

  • Angiotensin-converting enzyme (ACE) inhibitors to treat high blood pressure, and for people who have had a heart attack, have diabetes or kidney disease, or whose heart does not pump properly.
  • Angiotensin receptor blockers (ARBs) to treat high blood pressure and for people who have had a heart attack or have diabetes or kidney disease. Your doctor may recommend an ARB if you cannot take an ACE inhibitor or for other reasons.
  • Beta blockers to decrease the chance of irregular heart rhythms after CABG, as well as to treat high blood pressure and other heart conditions. These medicines slow your heart rate and lower your blood pressure to decrease the amount of stress on your heart.
  • Blood thinners, or anti-platelet medicines, to keep your graft from developing a blockage and help prevent blood clots. One type is aspirin. Your doctor will likely start you on aspirin right away, even before you get CABG surgery. Your doctor may prescribe other types of anti-clotting medicines, such as clopidogrel. Possible side effects of this medicine can include bleeding, especially if you are taking other medicines that also thin your blood, such as aspirin.
  • Calcium channel blockers to treat high blood pressure when beta blockers and ACE inhibitors do not control it.
  • Diuretics, or medicines to reduce the amount of fluid in your body or to treat high blood pressure when beta blockers and ACE inhibitors do not control it.
  • Statins to lower the amount of lipid in your blood and manage the cholesterol levels that can cause plaque. If you do not already take statins for your coronary artery disease, your doctor may recommend that you take statins before and after surgery.

Monitor your condition
- Coronary Artery Bypass Grafting

After surgery and after recovery, your doctor will want to schedule checkups to look for common complications of CABG or further problems from ischemic heart disease.

Even if you do not experience any signs or symptoms, you may need testing about five years after CABG surgery, or sooner if you have new symptoms or have other risk factors. You may take a stress test with an electrocardiogram or echocardiogram, or other heart and lung imaging. If you have symptoms such as chest pain, especially before or during the stress test, your doctor will likely recommend coronary angiography to check on the graft and other arteries.

Make healthy lifestyle changes
- Coronary Artery Bypass Grafting

Your doctor will discuss heart-healthy lifestyle habits and changes that are important to maintaining your health and controlling risk factors, such as hypertension and diabetes. These include:

Enroll in cardiac rehabilitation
- Coronary Artery Bypass Grafting

Your doctor may refer you to cardiac rehabilitation to improve your heart health after a heart-related procedure or heart condition. Cardiac rehabilitation helps you maintain or adopt heart-healthy lifestyle practices to lower your risk for cardiovascular diseases. This program includes exercise training, education on heart-healthy living, and counseling to reduce stress and help you return to an active life. These rehabilitation programs are supervised by doctors and are usually offered in hospitals or community facilities.

Monitor your emotional health
- Coronary Artery Bypass Grafting

Your doctor will likely ask if you have had any changes in your mood or other aspects of your well-being. It is important to be treated for depression to increase your chance of full recovery.

If you have symptoms of depression, your doctor may refer you to a mental health specialist. Treatment may include counseling and medicine.

Learn the warning signs of complications and have a plan
- Coronary Artery Bypass Grafting

Complications can occur quickly or years after CABG. One possible complication is that the graft will become blocked with plaque and limit or stop blood flow to the heart. If your graft stops working, this may cause a heart attack or other problem with your heart, and you may need additional surgery or PCI.

If you think that you are or someone else is having the following symptoms, call 9-1-1 right away. Every minute matters.

  • Heart attack. Signs of heart attack include mild or severe chest pain or discomfort in the center of the chest or upper abdomen that lasts for more than a few minutes or goes away and comes back. It can feel like pressure, squeezing, fullness, heartburn, or indigestion. There may also be pain down the left arm. For those who have had a heart attack in the past, the symptoms may be similar to the previous heart attack. Read more about the signs and symptoms of a heart attack.
  • Stroke. If you think someone may be having a stroke, act F.A.S.T. and do the following simple test.
    • F—Face: Ask the person to smile. Does one side of the face droop?
    • A—Arms: Ask the person to raise both arms. Does one arm drift downward?
    • S—Speech: Ask the person to repeat a simple phrase. Is their speech slurred or strange?
    • T—Time: If you observe any of these signs, call for help immediately. Early treatment is essential.
    Read more about the signs and symptoms of a stroke.

Research for Your Health

The NHLBI is part of the U.S. Department of Health and Human Services’ National Institutes of Health (NIH)—the Nation’s biomedical research agency that makes important scientific discovery to improve health and save lives. We are committed to advancing science and translating discoveries into clinical practice to promote the prevention and treatment of heart, lung, blood, and sleep disorders including coronary artery bypass grafting (CABG) procedures. Learn about current and future NHLBI efforts to improve health through research and scientific discovery.

Improving health with current research
- Coronary Artery Bypass Grafting

Learn about the following ways the NHLBI continues to translate current research into improved health for people who need coronary artery bypass grafting. Research on this topic is part of the NHLBI’s broader commitment to advancing heart and vascular disease scientific discovery.

  • NHLBI Workshop on Future Directions for Research on Coronary Heart Disease Therapy. We support workshops that provide guidance for research priorities. In 2010, the NHLBI held a workshop to discuss how to support studies that can more effectively guide treatment decisions for people who have coronary heart disease, such as when a stent would be the best treatment.
  • Addressing Barriers to Early Diagnosis and Treatment. We fund the Vascular Interventions/Innovations and Therapeutic Advances (VITA) Program, a translational program that supports and accelerates early stage development of promising diagnostics and treatments, such as CABG. VITA seeks to address unmet clinical needs for vascular diseases, particularly in underserved medical communities.
  • Studying Innovations to Improve Heart and Vascular Disease Outcomes. The Cardiothoracic Surgical Trials Network (CTSN) is an international clinical research enterprise that studies heart valve disease, arrhythmias, heart failure, coronary heart disease, and the complications of CABG and other surgery. The trials range from early translation to the completion of six randomized clinical trials, three large observational studies, and many other studies with more than 14,000 participants.
  • Providing Evidence for Guidelines in Treating Patients Who Have Diabetes. The international NHLBI-supported study, Future Revascularization Evaluation in Patients with Diabetes Mellitus: Optimal Management of Multivessel Disease (FREEDOM), found that adults who had diabetes and ischemic heart disease who underwent CABG surgery had fewer complications than those who had a stent placed. The landmark Bypass Angioplasty Revascularization Investigation 2 Diabetes (BARI 2D) study showed that CABG was better than medicines alone at lowering the risk of life-threatening heart attack and stroke. Both FREEDOM and BARI 2D provided evidence for professional guidelines on treatment of stable ischemic heart disease patients with CABG.

Learn about some of our pioneering research contributions that have improved clinical care.

Advancing research for improved health
- Coronary Artery Bypass Grafting

In support of our mission, we are committed to advancing research on coronary artery bypass grafting, in part through the following ways.

Learn about exciting research areas the NHLBI is exploring that involve CABG.

Participate in NHLBI Clinical Trials

We lead or sponsor many studies on coronary artery bypass surgery and heart disease treatments. See if you or someone you know is eligible to participate in our clinical trials.

More Information

After reading our Coronary Artery Bypass Grafting Health Topic, you may be interested in additional information found in the following resources.

Non-NHLBI resources
- Coronary Artery Bypass Grafting