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Risks - Coronary artery bypass graft

As with all types of surgery, a coronary artery bypass graft (CABG) carries risks of complications.

Irregular heartbeat

Some people develop atrial fibrillation. This is a condition that causes an irregular and often abnormally fast heart rate.

Atrial fibrillation is common but usually does not last long following heart surgery. It is can be managed with medicines.


The wounds in your chest and arm or leg can become infected after a coronary artery bypass graft.

Infection can also affect your lungs or the inside of your chest after having the surgery.

Most infections that develop after the procedure can usually be treated successfully. Any infections are treated with antibiotic tablets or injections.

Reduced kidney function

Some people experience reduced kidney function after surgery.

In most cases, this is only temporary and the kidneys begin working normally after a few days or weeks.

In rare cases, you may need to have temporary dialysis until your kidneys recover.

Dialysis is where you are attached to a machine that replicates the functions of the kidneys.

Brain-related problems

Some people experience problems with their memory after a coronary artery bypass graft. They also find it difficult to concentrate on things like reading a book or newspaper.

This will usually improve in the months following the operation. But it can sometimes be permanent.

There's also a risk of serious problems affecting the brain during or after a coronary artery bypass graft. For example, a stroke.

Risks of developing complications

Following a coronary artery bypass graft, there are several factors that increase your risk of developing complications.

These include:

Your age

Your risk of developing complications after surgery increases as you get older.

Having another serious long-term health condition 

Having a condition such as diabetes, chronic obstructive pulmonary disease (COPD) or severe chronic kidney disease can increase your risk of complications.

Being a woman 

Women tend to develop coronary artery disease later than men. It's thought this may lead to a higher risk of experiencing complications. This is because women are generally older at the time of surgery.

Having emergency surgery to treat a heart attack

Emergency surgery is always riskier.

This is because:

  • there's less time to plan the surgery
  • the heart can be seriously damaged from the heart attack

Having 3 or more vessels grafted

The more complex the operation, the greater the chance that complications will happen.


If you have obesity, the surgeon will have to make a deeper cut to gain access to your heart. Deeper cuts have a higher risk of becoming infected.

Your surgical team will be able to give you more information about any risks before you have surgery.

Content supplied by the NHS and adapted for Ireland by the HSE

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This project has received funding from the Government of Ireland’s Sláintecare Integration Fund 2019 under Grant Agreement Number 123.

Page last reviewed: 10 August 2021
Next review due: 10 August 2024