Introduction of abdominal aortic aneurysm

An aneurysm is a bulge in a blood vessel caused by a weakness in the blood vessel wall. As blood passes through the weakened blood vessel, the blood pressure causes it to bulge outwards like a balloon.

Exactly what causes the blood vessel wall to weaken is unclear, though hardening of the arteries, smoking and high blood pressure are thought to increase the risk of an aneurysm.

Read more about the possible causes of an aneurysm.

Aneurysms can occur anywhere in the body, but the two most common places for them to form are in the abdominal aorta and the brain.

This topic is about abdominal aortic aneurysms. Find out more about brain aneurysm.

The abdominal aorta

The abdominal aorta is the largest blood vessel in the body. It is roughly the width of a garden hose. It transports oxygen-rich blood away from the heart to the rest of the body.

It runs in a straight line down from the heart, through the chest and abdomen before branching off into a network of smaller blood vessels.

In most cases, an abdominal aortic aneurysm causes no noticeable symptoms and does not pose a serious threat to health.

However, there’s a risk that a larger aneurysm could burst open (rupture). A ruptured abdominal aortic aneurysm can cause massive internal bleeding, which is usually fatal. Four out of five people with a ruptured aortic aneurysm will die as a result.

The most common symptom of a ruptured aortic aneurysm is sudden and severe pain in the abdomen.

If you suspect that you or someone else has had a ruptured aneurysm, call 999 immediately and ask for an ambulance.

Read more about the symptoms of an abdominal aortic aneurysm.


The aim of treatment is to prevent the aneurysm from rupturing. This is usually done with surgery to replace the weakened section of the blood vessel with a piece of synthetic tubing.

However, preventative surgery carries a small risk of causing serious complications. It’s usually only recommended if it’s thought that the risk of a rupture is high enough to justify the risk of surgery.

The size of the aneurysm is often used to measure the risk of it rupturing. Preventative surgery is often recommended for an abdominal aortic aneurysm that’s larger than 5.5cm.

A number of non-surgical treatments can also be used to reduce the risk of an aneurysm rupturing. They include a type of medication known as a statin, or quitting smoking if you smoke.

Read more about treating abdominal aortic aneurysm.


In March 2009, the NHS launched a screening service to check men who are 65 years old or over for abdominal aortic aneurysms. The service is expected to cover the whole of England by April 2013 and is being introduced in Wales later in the year.

If you don’t live in a part of the country that’s currently covered by the scheme, you can ask your GP to refer you for screening if you or they feel that you have an increased risk of having an aortic aneurysm. For example, this might be the case if you’re over 65 and are a heavy smoker.

Who is affected?

Abdominal aortic aneurysms are most common in men aged over 65, with around in 1 in 25 men being affected.

The number of aortic aneurysms that rupture is much smaller, with only around 1 in 10,000 people having a ruptured aortic aneurysm in any year in England.


The best way to prevent getting an aneurysm, or reduce the risk of an aneurysm growing bigger and possibly rupturing, is to avoid any activities that could damage your blood vessels, such as:

  • smoking
  • eating a high-fat diet
  • not exercising regularly
  • being overweight or obese

Read more about preventing aneurysms.

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