A coronary artery bypass graft (CABG) is a surgical procedure used to treat coronary heart disease.

It diverts blood around narrowed or clogged parts of the major arteries to improve blood flow and oxygen supply to the heart. 

Around 20,000 CABG procedures are performed in England every year. Most of these are carried out in men and around 80% are used to treat people who are at least 60 years old.

Why they are carried out

Like all organs in the body, the heart needs a constant supply of blood. This is supplied by two large blood vessels called the left and right coronary arteries.

Over time, these arteries can become narrowed and hardened by the build-up of fatty deposits called plaques. This process is known as atherosclerosis. People with atherosclerosis of the coronary arteries are said to have coronary heart disease.

Your chances of developing coronary heart increase with age and you are much more likely to be affected by the condition if you smoke, if you're overweight or obese, and if you eat a high-fat diet.

Coronary heart disease can cause angina, which is chest pain that occurs when the supply of oxygen-rich blood to the heart becomes restricted. While many cases of angina can be treated with medication, severe angina may require a CABG to improve the blood supply to the heart.

Another risk associated with coronary heart disease is that one of the plaques in the coronary artery ruptures (splits), creating a blood clot. The blood clot can block the supply of blood to the heart, triggering a heart attack. Therefore, a CABG may also be recommended to reduce your chances of having a heart attack.

The procedure

A CABG involves taking a blood vessel from another part of the body – usually the chest, leg or arm – and attaching it to the coronary artery above and below the narrowed area or blockage. This new blood vessel is known as a graft.

The number of grafts needed will depend on how severe your coronary heart disease is and how many of the coronary blood vessels have become narrowed.

A CABG is carried out under general anaesthetic, which means you will be asleep during the operation. It usually takes between three and six hours.

Read more about preparing for a coronary artery bypass graft and how a coronary artery bypass graft is performed.

Recovery

Most people will need to stay in hospital for at least seven days after a CABG.

Recovery from a CABG takes time and everyone recovers at slightly different speeds. Generally, you should be able to sit in a chair after one day, walk after three days and walk up and down stairs after five or six days.

When you go home, you will need to take things easy for a few weeks. You will usually be able to return to most of your normal activities after about six weeks, including working, driving, and having sex – most people make a full recovery within 12 weeks.

Read more about recovering from a CABG.

Risks of surgery

As with all types of surgery, a CABG carries a risk of complications.

These are usually relatively minor and treatable, such as an irregular heartbeat or a wound infection, but there is also a risk of serious complications such as a stroke or heart attack.

Overall, more than 95% of people who have a CABG will live for at least one year and around 90% will live at least five years.

Read more about the risks of a coronary artery bypass graft

After surgery

After a CABG, most people will experience a significant improvement in symptoms such as breathlessness and chest pain, and their heart attack risk will be lowered.

However, it is important to realise that a CABG is not a cure for coronary heart disease. If you do not make lifestyle changes, such as eating a healthy diet and exercising regularly, your grafted arteries will eventually become hardened and narrowed too.

In some cases, a CABG may need to be repeated or you may need a procedure to widen your arteries using a small balloon and a tube called a stent (coronary angioplasty).

Read more about healthy living after a coronary artery bypass graft.

Are there any alternatives?

The main alternative to a CABG is a coronary angioplasty. This is a less invasive operation that involves inserting a long, flexible hollow plastic tube called a catheter into a blood vessel in your arm or groin.

A balloon attached to the catheter is then inflated to widen the artery and a small metal tube called a stent is often used to help keep the artery open.

Recovery from a coronary angioplasty is usually faster than after a CABG, but there is a higher chance that the procedure will need to be repeated and it may not be recommended if multiple coronary arteries have become blocked and narrowed or the structure of the blood vessels near your heart is abnormal.

Read more about the alternatives to a coronary artery bypass graft.

Artery

Arteries are blood vessels that carry blood from the heart to the rest of the body.

Blood

Blood supplies oxygen to the body and removes carbon dioxide. It is pumped around the body by the heart.

Blood vessels

Blood vessels are the tubes in which blood travels to and from parts of the body. The three main types of blood vessels are veins, arteries and capillaries.

Bypass

A bypass is when the flow of blood or other fluid is redirected, permanently because of a blockage in the body, or temporarily during an operation.

Coronary angioplasty

Coronary angioplasty is surgery to open up arteries in the heart that have been blocked or narrowed by fatty deposits.

Heart

The heart is a muscular organ that pumps blood around the body.

Oxygen

Oxygen is an odourless, colourless gas that makes up about 20% of the air we breathe.