Published by Bupa's health information team, August 2008.
This factsheet is for people who have an abdominal aortic aneurysm (AAA), or who would like information about it.
An AAA is a widening or bulge in the aorta (the largest artery in the body). An AAA usually occurs at a weak spot in the aortic wall. If your AAA ruptures (bursts) it can be fatal so you may need surgery to repair it.
The aorta carries all the blood that is pumped out of your heart and distributes it, via its many branches, to all the organs of your body. The aorta projects upwards from your heart and then turns downwards, travelling through your chest (the thoracic aorta) and into your abdomen (the abdominal aorta).
The normal diameter of the abdominal aorta is around 2 to 3cm (about one inch).
An aortic aneurysm is a thin, weakened section of the wall of your aorta that bulges outward. Most aneurysms occur in the section of the aorta that passes through your abdomen and are called abdominal aortic aneurysms.
Aneurysms can also occur in the part of your aorta that is near your heart; these are called thoracic aortic aneurysms. This factsheet will only discuss AAAs.
The artery wall of an aneurysm is weaker than normal artery wall so it may not withstand the pressure of blood inside. This may cause it to rupture.
The chance of an AAA rupturing depends on its size. If your aneurysm is greater than 5.5cm wide the chances of rupture are higher - and the risk increases with increasing size.

Abdominal aortic aneurysm
You could have an AAA for years before you develop any symptoms and you may not get any at all. If you have an AAA you may have:
If your AAA becomes very large and ruptures it can cause excruciating pain. You may also have a lump in your abdomen that expands and contracts. A ruptured AAA causes severe internal bleeding which is often fatal unless emergency surgery to repair the rupture is carried out.
The main cause of AAAs is atherosclerosis. This is a condition in which fatty deposits are laid down in the walls of your arteries. The deposit is called an atheroma. This weakens your artery walls and makes them less elastic and weaker as a result.
You are more likely to develop atherosclerosis, and therefore an AAA, depending on:
Abdominal AAs can be diagnosed from your symptoms when they occur but this may be too late. They are usually found when you have a routine physical examination and chest and abdominal X-rays.
When your doctor examines you, he or she may feel a pulsating mass in your abdomen which may be tender if your AAA is large. If your doctor suspects an AAA, he or she will request tests including those below.
At present there isn't a national screening programme to detect AAAs. However, the Government is considering plans to introduce a programme.
Your treatment for an AAA will depend on your symptoms and the size of your aneurysm.
Emergency surgery is needed if your AAA ruptures. This is a major operation and carries significant risks. A number of people will die during, or shortly after, an emergency operation. The decision to have surgery is based on the size of your aneurysm.
If you have a small AAA, the risk of death caused by surgery is higher than the risk of rupture. Surgery isn't usually advised but you will need regular ultrasound checks to see if your AAA grows over time. It's also important to manage your condition by changing your lifestyle - for more information see Prevention.
For larger aneurysms the risk of rupture is usually higher than the risks of surgery. However, this will depend on your personal state of health. For some people the risks of surgery will still outweigh the benefits.
Surgery is usually advised if your aneurysm is:
Your doctor will advise you if surgery is the best treatment for you.
There are two main surgical options for an AAA. Both are usually done under general anaesthetic. This means you will be asleep during the operation.
In the traditional surgical method, your surgeon will make an opening in your abdomen. Your aorta will then be opened at the site of the aneurysm and be replaced with a graft. The graft can be made with a piece of blood vessel taken from another place in your body or it can be synthetic. A synthetic graft is made out of an elastic material and is similar to your normal healthy aorta. It gives your artery support to prevent the aneurysm getting bigger. This procedure can also be performed using keyhole surgery.
A Flash plug-in is required to view this animation.
Legal notices
Alternatively your surgeon may place a stent-graft into your aorta. A stent-graft is a graft placed over an artificial piece of rigid tubing called a stent. This is a recently developed technique and isn't suitable for everyone. A small cut will be made in your groin and the stent-graft will be passed up inside one of your leg arteries until it reaches the area of your aneurysm. The stent will be positioned so that your blood vessel is repaired and the aneurysm is protected from further pressure. This method doesn't involve open surgery.
A Flash plug-in is required to view this animation.
Legal notices
Your surgeon will advise you which procedure is best for you.
There are several things you can do to reduce your chance of developing an aneurysm:
You should also have regular medical check ups if you have a family history of arterial disease so that any problems can be detected early.
See our answers to common questions about abdominal aortic aneurysm, including:
This information was published by Bupa's health information team and is based on reputable sources of medical evidence. It has been peer reviewed by Dr Tim Cripps, DM, FRCP; Bristol Royal Infirmary, Bristol, and by Bupa doctors. It has also been reviewed by The Circulation Foundation. The content is intended for general information only and does not replace the need for personal advice from a qualified health professional.
Publication date: August 2008.
Have you found the information in this factsheet helpful? Do take a couple of moments to give us your feedback.