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Coronary Artery Bypass


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​​​​​​​​​​​​​​​​​​​Coronary artery bypass surgery restores blood flow to the heart after arteries become blocked due to disease.

Your Marshfield Clinic Cardiologist may suggest the surgery after tests show artery blockage.

The surgery is also performed on an emergency basis following a heart attack.​


Front view of heart with three bypass grafts.If 1 or more of your coronary arteries (the vessels that carry blood to your heart muscle) are blocked, blood can’t flow to the heart muscle. In this case, the heart muscle may die (heart attack) or become weakened and damaged and cause chest pain (angina). Problems like shortness of breath, increasing fatigue, leg swelling, or feeling run down may occur. Coronary artery bypass surgery creates a path for blood to flow around a blockage and helps reduce the risk of further damage to your heart from lack of sufficient blood flow and may reduce symptoms of angina or shortness of breath. 

Preparing the bypass graft

First, a healthy blood vessel (graft) is taken from another part of the body. Taking this graft usually doesn't affect blood flow in that body part. If you have more than 1 blockage, which is often the case,more than 1 graft may be needed. Sometimes the doctors will do special ultrasound tests to look at the possible grafts prior to surgery. One or more of these blood vessels will be used for the graft:

  • The saphenous vein, which is located in the leg.

  • The radial artery, which is located by the wrist.

  • The internal thoracic (mammary) arteries, which are located in the chest wall. There are 2 internal thoracic arteries, 1 on each side of the chest. Typically, the left one is used, but sometimes both are used.

Reaching the heart

While 1 member of the bypass team is harvesting the graft(s), another member works to expose your heart. First, an incision is made in the chest. Then the breastbone (sternum) is opened down the middle and then pulled apart. The breastbone is held open throughout surgery. This puts pressure on the nerves of the chest. This is why you may have soreness and muscle spasms in your chest, shoulders, and back during recovery.

Attaching the graft

A small opening is made in the coronary artery, past the blockage:

  • If a saphenous vein or radial artery is used, 1 end of the graft is sewn onto this opening. The other end is typically sewn on to the aorta. The diseased artery is not removed. If a stent is present, it is not removed either, as the stent will already have become a permanent part of the artery.

  • If the internal thoracic (mammary) artery is used, 1 end of the graft is sewn onto this opening. The other end is already attached to a branch of the aorta.

Finishing up

Once the graft has been attached, blood will start flowing through this new pathway to bypass the blockage. If you have multiple blockages, more than 1 bypass may be done. Then your breastbone is rejoined with wires. These wires will stay in your chest permanently. Rarely do they cause a problem, and they are safe around microwaves and airport metal detectors. The incision is closed, and you are taken to the intensive care unit to begin your recovery.

Using a heart-lung machine

Coronary artery bypass surgery can be done with the heart still beating (off pump) or with the heart still (on pump.) Your surgery team can tell you more about which type of procedure you will have:

  • On-pump procedure. A machine does the work of your heart and lungs during surgery. Blood is circulated through a heart-lung machine. The machine supplies the blood with oxygen and pumps it back through the body. In these cases, the heart may be stopped temporarily before the graft is attached. Your own heart and lungs start working again after the bypass is completed.

  • Off-pump procedure. The heart-lung machine is not used and the heart is not stopped. This is sometimes called a "beating heart" procedure.

There are advantages and disadvantages to each technique. If you have a question about why your doctor is using 1 technique, instead of the other, do not be afraid to ask.


Risks and complications

You and your surgeon can discuss the risks and possible complications of coronary artery bypass surgery. They may include:

  • Excessive bleeding, sometimes requiring a transfusion or a trip back to the operating room

  • Infection of the incision sites

  • Pneumonia (lung infection)

  • Fast or irregular heartbeat, which is almost always temporary 

  • Nerve injury or muscle spasms

  • Breathing problems

  • Memory problems or confusion

  • Heart attack, stroke, or death

  • Damage to other parts or organs of your body due to problems with blood circulation

 Coronary Bypass Video

What Do You Know About Preventing Heart Disease?

You can take steps to reduce your risk for heart disease. Find out more about preventing heart disease by taking this quiz.

1. Which of these is a cause of heart disease?
2. What can happen if blood flow in an artery is blocked or greatly restricted?
3. Three risk factors for heart disease can't be controlled. Which of these are they?
4. What is considered "high blood pressure"?
5. Why can smoking lead to heart disease?
6. How much exercise is recommended to help prevent heart disease?
7. Your risk for heart disease rises if your body mass index (BMI) is more than 24.9. Why?
8. Drinking a moderate amount of alcohol is considered safe for your heart. What can happen if you drink more?
9. Which of these is a classic symptom of a heart attack?