Coronary artery bypass grafts

What is coronary artery bypass grafting?

Coronary artery bypass grafting is a type of surgery to improve blood flow to the heart. It is used to treat people who have severe coronary heart disease.

What does the cardiovascular system do?

The cardiovascular system is responsible for moving vital nutrients, gases and hormones around the body. It is made up of the heart, lungs and blood vessels, all working together.

More about the cardiovascular system

What is coronary artery disease?

Coronary arteries are the blood vessels that carry blood, oxygen and other nutrients to the heart. As we get older, our coronary arteries can become hardened and fatty deposits can build up inside their inner lining. This process (called atherosclerosis) causes narrowing of the arteries and reduces the blood supply to the heart muscle.

The three main coronary arteries are the:

  • left anterior descending artery
  • circumflex artery
  • right coronary artery.

What is a coronary artery bypass graft?

During coronary artery bypass surgery, a healthy artery or vein from the body is grafted (connected) to the blocked coronary artery. The grafted artery or vein bypasses (that is, goes around) the blocked portion of the coronary artery, creating a new path for the blood to flow to the heart muscle.

First, a general anaesthetic is given. Then, an incision is made down the length of the sternum (breast bone) to access the heart. Blood is diverted from the heart to a machine called a cardiopulmonary bypass machine. The surgeon takes one or more veins from the legs, chest or arms and uses it to bypass the blocked artery. Multiple coronary arteries bypasses can be done if there are several blocked vessels.

What happens in intensive care?

After someone has had coronary artery bypass surgery, they are admitted to the intensive care unit (ICU). Initially, they will have a breathing tube inserted, which will be attached to a ventilator. As they become better able to breathe on their own, they will be taken off the ventilator. Once their breathing is stable, the breathing tube will be removed.

If you visit someone in the ICU at this stage, you can expect to see many lines, tubes and drains attached to them.

In the first 24 hours after surgery, their care will include:

  • continuous monitoring of the heart rate, blood pressure, oxygen level and body temperature
  • monitoring of drainage from chest tubes.
  • monitoring of kidney function, by use of a urinary catheter.

Most patients will only need to stay one or two days in the ICU and can usually go home five to seven days later. However, if there are complications following surgery, they may need to stay in the ICU for weeks or even months.

Possible complications following cardiac surgery include:

What is life like after coronary artery bypass graft surgery?

Once someone has left the ICU, they are given support and prepared for their return home by a team of professionals, including doctors, nurses, physiotherapists, occupational therapists, dieticians, pharmacists and social workers. They will be encouraged to attend a cardiac rehabilitation program that offers:

  • education sessions
  • supervised exercise programs
  • an opportunity to meet other people who have had heart surgery.

Some people find they feel tired and have difficulty concentrating after heart surgery. This is common, and usually improves within four to eight weeks. If you have any concerns, please discuss them with your doctor.

Useful links

Publication details

Version 1.1. First published 2015. Revised January 2023. Next review 2028.


The information on this page is general in nature and cannot reflect individual patient variation. It reflects Australian intensive care practice, which may differ from that in other countries. It is intended as a supplement to the more specific information provided by the doctors and nurses caring for your loved one. ICNSW attests to the accuracy of the information contained here but takes no responsibility for how it may apply to an individual patient. Please refer to the full disclaimer.