Abdominal Aortic Aneurysm (AAA) - General Information

What is the aorta?

The aorta is the largest artery (blood vessel) in the body. It carries blood from the heart and runs down through the chest and the abdomen (tummy). Many arteries come off the aorta to supply blood to all parts of the body. At about the level of the pelvis, the aorta divides into two iliac arteries, one going to each leg.

 

What is an Abdominal Aortic Aneurysm (AAA)?

An aneurysm occurs when the wall of a blood vessel weakens and balloons out. In the aorta, this ballooning makes the wall weaker and more likely to burst. Aneurysms can occur in any artery, but most commonly occur in the section of the aorta that passes through the abdomen. These are known as abdominal aortic aneurysms (AAA).

 

What causes an AAA?

The exact reason why an aneurysm forms in the aorta is not clear in most cases. Aneurysms can affect men or women of any age. However, they are most common in men, people with high blood pressure (hypertension), and those over the age of 65.

The wall of the aorta normally has layers of supporting tissues. As people age, they may lose some of this tissue. This is thought to explain why aneurysms are more common in older people.

Your genetic make-up plays a role, as you have a much higher chance of developing an AAA if one of your immediate relatives (parent, brother, or sister) has or had one. Other risk factors that increase the chance of getting an aneurysm include smoking, high blood pressure, high cholesterol, emphysema, and obesity.

It is estimated that about 4 in 100 men over the age of 65 will develop an abdominal aortic aneurysm, though not all will be of significant size, and about 1 in 100 will have a large aneurysm requiring surgery. They are about 6 times rarer in women.

 

How are aneurysms discovered?

The majority of AAAs cause no symptoms and are discovered by chance. A routine examination by a doctor or an x-ray or scan performed for some other reason may pick up the presence of an aneurysm. In some cases, patients notice an abnormal pulse in their abdomen. As the aneurysm stretches, it can also cause pain in your back or abdomen.

The NHS AAA Screening Programme screens men aged 65 and over. Screening is performed using an ultrasound scan of the abdomen. This is a quick and painless test and is similar to the scans done on pregnant women to show a picture of their baby. The scan shows if there is an aneurysm present and how large it is. Men are given their result straight away.

Men are invited for screening during the year they turn 65. Men over 65 who have not previously been screened can contact their local screening centre directly to organize a scan.

 

Where is screening offered?

The NHS AAA Screening Programme is being introduced gradually to make sure it works as effectively as possible. Visit http://aaa.screening.nhs.uk/whereyoulive for details of where screening is available and for contact details for the local screening programmes. By 2013, screening will be offered to all men in England in their 65th year.

 

Possible Results of Screening

• Normal (no aneurysm detected): Aortic diameter less than 3 cm – most men have a normal result, require no further scans, and are discharged from the screening programme.
• Small aneurysm: Aortic diameter 3-4.4 cm – men are invited back for an annual surveillance scan to check the growth rate of the aneurysm.
• Medium aneurysm: Aortic diameter 4.5-5.4 cm – men are invited back for three-monthly surveillance scans to check the growth rate of the aneurysm.
• Large aneurysm: Aortic diameter 5.5 cm and above – men are referred to a consultant vascular surgeon to discuss treatment options, usually surgery.

 

What are the symptoms of an AAA?

Aneurysms generally take years to develop, and it is rare for them to give symptoms during this time.

If you do develop symptoms, you may experience one or more of the following:

• A pulsing feeling in your abdomen similar to a heartbeat.
• Pain in your abdomen or lower back.

 

Do I need an operation to treat my aneurysm?

Research has shown that for people with AAAs measuring less than 5.5 cm (about 2 inches), it is safer not to operate as the risks of having an operation are greater than the benefit.

If an aneurysm measures 5.5 cm or over, starts to produce symptoms, or rapidly increases in size, you will be referred to a vascular surgeon to discuss treatment options, usually surgical repair. There are two types of operations that can be done to repair an aneurysm:

• Open surgery: This involves an incision in the abdomen and replacement of the affected section of the blood vessel with a fabric tube.
• Endovascular (EVAR) surgery: This is a form of keyhole surgery using a stent graft.

If your surgeon recommends an operation, they will give you more information. You can also find more details of these procedures in our leaflets.

 

Why do I need to have my aneurysm checked regularly?

If you have a small aneurysm (3-4.5 cm aortic diameter), it is important to monitor its growth. Most aneurysms grow very slowly; so many men with a small aneurysm will never need treatment.

However, if an AAA gets bigger, there is an increased risk that it may leak or burst without any warning.

 

What is the chance of a small AAA rupturing?

The chance of rupture is very low for small AAA. For aneurysms measuring less than 5.5cm in diameter the risk of rupture is less than 1 in 100 per year. As aneurysms get larger than 5.5cm, the risk of rupture increases and it is usually at this size that the option of surgery is considered. For any given size, rupture risk is increased in smokers, those with high blood pressure, and those with a family history of an AAA.

Each individual’s risk from their AAA and from surgery may be different so any decision on treatment will be carefully considered by the vascular team and always discussed in detail with you and, when appropriate, your family.

 

Do I need to take things easy?

If you have been told you have an aneurysm, there is no need to limit your everyday activity. Moving around, lifting, and exercise will not affect your aneurysm or cause damage.

 

What do I do if I get new symptoms?

If you experience sudden onset of new severe abdominal pain or back pain that is distinct from any back pain you may have had previously, you may be developing a leak from your AAA, or it may be at immediate risk of rupture.

If you experience any of these symptoms, you should dial 999 for an ambulance and tell the ambulance control that you have an abdominal aortic aneurysm and need to go urgently to the hospital.

DO NOT DRIVE YOURSELF TO HOSPITAL.

 

Whilst we make every effort to ensure that the information contained in this patient information sheet is accurate, it is not a substitute for medical advice or treatment, and the Circulation Foundation recommends consultation with your doctor or health care professional. The information provided is intended to support patients, not provide personal medical advice. The Circulation Foundation cannot accept liability for any loss or damage resulting from any inaccuracy in this information or third party information such as information on websites to which we link.