Abdominal aortic aneurysm

An abdominal aortic aneurysm or AAA is a balloon-like swelling of your aorta, the main artery in your body. 


Illustration of a heart showing the main arteriesYour aorta carries oxygen-rich blood away from your heart to the rest of your body and your brain. AAA occurs in the part of your aorta that passes through your abdomen (your tummy area).

Your abdominal aorta is usually about 2cm wide or about the width of a garden hose. If you have an aneurysm it can grow to over 5.5cm. This is classed as a large aneurysm and will need to be checked by a surgical specialist.

AAA affects more men than women and your risk increases over the age of 65.

Symptoms of abdominal aortic aneurysm

A large aneurysm can burst and cause internal bleeding. This is a medical emergency and you should call 999 immediately if you or someone with you has any of these symptoms:
  • a sudden severe pain in the abdomen, back or lower back area
  • feeling cold, clammy, sweaty, faint and breathless
  • loss of consciousness

In most cases there are no noticeable symptoms and most people with AAA won’t be aware that they have one.

However if an aneurysm becomes large it can cause pain, a pulsating feeling in your abdomen, or persistent back pain.

How is AAA diagnosed?

AAA is sometimes picked up during tests for other conditions, commonly by 

  • ultrasound
  • CT 
  • MRI scan
Because most people with AAA don’t have symptoms, there is a screening programme in place in the UK. 

Screening programme 

AAA is far more common in men over 65. For this reason, all men are invited for a screening test when they turn 65. This test involves a simple ultrasound scan and takes around 10-15 minutes. 

If you are female or under 65 and think that you may have AAA or are at risk of developing it, then speak to your GP about the possibility of being referred for an ultrasound scan.

You can find out more about the screening programme on the NHS website.

Treatment for abdominal aortic aneurysm

Most aneurysms are small (between 3 and 5.4 cm) and won’t need treatment. But they can grow, so if you have AAA you will need regular scans to check the size of yours. If your aneurysm grows, the risk of it bursting becomes higher. 

If it grows to more than 5.5 cm you will be referred to a surgical specialist to discuss treatment.

There are two main treatments available for AAA:

  • Surgical repair involves replacing the affected part of your aorta with a plastic tube (graft). It is a big operation and you will need a general anaesthetic, so you will be asleep for the procedure. Most people who have this operation need to stay in hospital for over a week and it can take some weeks to make a full recovery.
  • Endovascular repair (EVAR) is a type of keyhole surgery. This involves placing a stent-graft (a small metal tube covered with a mesh) inside the artery through a small cut in the groin. If you have this procedure you will usually have a local anaesthetic, although some people might need a general anaesthetic. You should be able to get up and walk around the next day. Most people are able to go home two or three days afterwards. Although this is a simpler and safer procedure than open surgery, it’s not suitable for everyone. Your surgeon will discuss your options with you.

Causes of AAA

It’s not known exactly what causes abdominal aortic aneurysm although it is linked to atherosclerosis and the build-up of fatty material in your arteries. The biggest risk factors are age and being male and you also have an increased risk of developing AAA if you have a family history of it. 

There are other risk factors that you can do something about:

Taking these steps can also help reduce the risk of your AAA growing larger if you already have one.

Want to know more?

Order or download our publications:

 Peripheral arterial disease  Atherosclerosis - your quick guide