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Coronary Artery Bypass Surgery

Surgery Overview

Coronary artery bypass is surgery to treat coronary artery disease. It helps blood make a detour, or bypass, around one or more narrowed or blocked coronary arteries. These arteries are the blood vessels that bring blood to the heart. This is also called coronary artery bypass graft (CABG) or bypass surgery.

Your doctor will make the bypass with a healthy piece of blood vessel from another part of your body. Then the doctor will attach, or graft, the healthy blood vessel to the narrowed or blocked artery. The new blood vessel bypasses the diseased artery to increase blood flow to the heart muscle.

The doctor will make a cut in the skin over your breastbone (sternum). This cut is called an incision. Then the doctor will cut through your sternum to reach your heart and coronary arteries. The doctor may connect you to a heart-lung bypass machine. It adds oxygen to the blood and moves the blood through the body. The machine will allow the doctor to stop your heartbeat while working on your arteries. The doctor will use blood vessels from your chest, arm, or leg to bypass the narrowed or blocked parts of your arteries. When the blood vessels are in place, the doctor will restart your heart. In some cases, the doctor may be able to do the surgery without using a heart-lung machine. This is called "off-pump" surgery.

The doctor will use wire to put your sternum back together. Stitches or staples will be used to close the incisions in the skin over your sternum and where your healthy blood vessel was taken. The wire will stay in your chest. The incisions will leave scars. They may fade with time.

You will stay in the hospital for 3 to 8 days after surgery. You will probably be able to do many of your usual activities after 4 to 6 weeks. But for 2 to 3 months you will not be able to lift heavy objects or do activities that strain your chest or upper arm muscles. At first you may notice that you get tired easily and need to rest often. It may take 1 to 2 months before your energy is back to normal.

How It Is Done

A coronary artery is narrowed or blocked

Heart, with detail of coronary artery narrowed by plaque
slide 1 of 5
slide 1 of 5, A coronary artery is narrowed or blocked,

Coronary artery bypass grafting (CABG) surgery reroutes blood around narrowed or blocked arteries, increasing blood flow to the heart muscle tissue.

The sternum is cut

Location of incision in chest
slide 2 of 5
slide 2 of 5, The sternum is cut,

The surgeon makes a vertical incision in the skin and muscle in the middle of the chest and then cuts through the breastbone (sternum).

The heart is exposed

Retractor exposing the heart in the chest
slide 3 of 5
slide 3 of 5, The heart is exposed,

The surgeon spreads the rib cage with a retractor to expose the heart and then cuts through the lining that protects the heart (pericardium).

Blood flow is rerouted

Location of saphenous vein in leg, and heart showing saphenous vein and an internal mammary artery used to bypass the diseased coronary artery
slide 4 of 5
slide 4 of 5, Blood flow is rerouted,

To reroute blood flow around the diseased blood vessel, surgeons typically use a portion of the saphenous vein in the leg or an internal mammary artery.

Oxygen-rich blood flows to heart muscle

Decreased blood flow caused by narrowed or blocked artery before surgery and normal blood flow after surgery
slide 5 of 5
slide 5 of 5, Oxygen-rich blood flows to heart muscle,

Regardless of which type of blood vessel is used, oxygen-rich blood from the aorta is rerouted around the narrowed or blocked section of the coronary artery to feed the heart muscle.

What To Expect

Right after surgery

After surgery, the first part of your hospital stay will include a short stay in the intensive care unit (ICU). You'll probably be there for 1 to 2 days before you go to your regular hospital room. In the ICU, you will likely have:

  • Continuous monitoring of your heart activity.
  • A tube to help with breathing for a while.
  • A stomach tube. It will remove stomach secretions until you start to eat again.
  • A tube (catheter) to drain the bladder and measure urine output.
  • Tubes connected to veins in the arms (intravenous, or IV, lines). You'll get fluids, nutrition, and medicine through these tubes.
  • An arterial line to measure blood pressure.
  • Chest tubes. These tubes drain the chest cavity of fluid and blood (which is temporary and normal) after surgery.

The amount of time you stay in the hospital varies. It will depend on your health before bypass surgery and whether complications develop from surgery.


You will stay in the hospital for at least 3 to 8 days after the surgery. You will feel tired and sore for the first few weeks. Your chest, shoulders, and upper back may ache. You may have some swelling or pain in the area where the healthy vein was taken. These symptoms usually get better in 4 to 6 weeks. It may take 1 to 2 months before your energy level is back to normal.

You will probably be able to do many of your usual activities after 4 to 6 weeks. But for 2 to 3 months you will not be able to lift heavy objects or do activities that strain your chest or upper arm muscles.

After surgery, you will still need to make changes in your lifestyle. This lowers your risk of a heart attack or stroke. To help the bypass last as long as possible:

  • Take your heart medicines.
  • Do not smoke.
  • Eat a heart-healthy diet.
  • Get regular exercise.
  • Stay at a healthy weight or lose weight if you need to.
  • Reduce stress.

Smoking can make it harder for you to recover. It will raise the chances of your arteries getting blocked again. If you need help quitting, talk to your doctor about stop-smoking programs and medicines. These can increase your chances of quitting for good.

You will likely start a cardiac rehabilitation (rehab) program in the hospital. This program will continue after you go home. It will help you recover. And it can prevent future problems with your heart. Talk to your doctor about whether rehab is right for you.

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Why It Is Done

Your doctor may recommend bypass surgery if:

  • Your left main heart artery is very narrow.
  • All three arteries of the heart are blocked or the amount of blood flowing through them is very low.
  • Your doctor thinks that bypass surgery will work better than angioplasty with stents.
  • You also need surgery to repair or replace a heart valve damaged by heart valve disease.
  • You have diabetes and two or more narrowed or blocked arteries.
  • Your heart is having trouble pumping. This is called a decreased ejection fraction.

Your choice may depend on the number of arteries that are affected or which arteries are affected. Talk with your doctor about the best treatment for you. The best treatment for you may also depend on your age, your health, and how much your angina is affecting your quality of life.

Not everyone with coronary artery disease needs bypass surgery. Some people can be helped by angioplasty with stents. Others use medical therapy, which involves making lifestyle changes and taking medicines. Some people use both of those treatments. Your doctor is likely to recommend bypass surgery only if you will benefit from it and if those benefits are greater than the risks.

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How Well It Works

Bypass surgery can:

  • Relieve angina symptoms and improve quality of life. You may be able to do more of your daily activities.footnote 1
  • Help some people live longer. Whether it could help you live longer depends on several things. These include your overall health and which arteries need to be bypassed. For example, the surgery may raise your chances of living longer if you have diabetes and narrowing in your heart's larger arteries.footnote 2, footnote 3


Bypass surgery has been done for more than 40 years. In Canada and the United States, it is one of the most common major surgeries. But it has some risks.

The chances of having a serious problem with bypass surgery increase with age. Your risk is also higher if you have other problems such as diabetes, kidney disease, lung disease, or peripheral arterial disease. Your doctor can help you understand what your risk for problems is.

The risks during or soon after bypass surgery include:

  • Infection.
  • Kidney problems.
  • Atrial fibrillation.
  • Heart attack.
  • Stroke.
  • Short-term problems with thinking and memory. This is more common in older people. It tends to get better within several months of surgery.
  • Death.



  1. Bravata DM, et al. (2007). Systematic review: The comparative effectiveness of percutaneous coronary interventions and coronary artery bypass graft surgery. Annals of Internal Medicine, 147(10): 703–716.
  2. Fihn SD, et al. (2012). ACCF/AHA/AATS/PCNA/SCAI/STS guideline for the diagnosis and management of patients with stable ischemic heart disease: A report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, and the American College of Physicians, American Association for Thoracic Surgery, Preventive Cardiovascular Nurses Association, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons. Circulation, 126(25): e354–e471.
  3. Fihn SD, et al. (2014). 2014 ACC/AHA/AATS/PCNA/SCAI/STS focused update of the guideline for the diagnosis and management of patients with stable ischemic heart disease. Circulation. DOI: 10.1161/CIR.0000000000000095. Accessed October 13, 2014.


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