Abdominal aortic aneurysm

At a glance

  • An aneurysm is a bulge in one part of a blood vessel.
  • Most aneurysms are harmless and don't cause any problems.
  • But it is life-threatening if an aneurysm in the largest blood vessel in the belly (the abdominal aorta) suddenly bursts.
  • Ultrasound can be used to find abdominal aortic aneurysms sooner.
  • Surgery can prevent them from bursting (rupturing), but is itself associated with risks.


Photo of a patient having an ultrasound examination

The aorta is the artery that carries oxygen-rich blood from the heart to the rest of the body. The part of the aorta that runs through the abdomen (belly) is called the abdominal aorta. It is usually about 2 cm in diameter (0.78 inches wide).

If one part of the abdominal aorta bulges outward and has a diameter of more than 3 cm (1.18 inches), it is known as an abdominal aortic aneurysm – sometimes abbreviated as AAA.

This kind of aneurysm usually goes unnoticed because it doesn't typically cause any problems. Most abdominal aortic aneurysms are harmless.

But there is a risk of the aorta suddenly rupturing (breaking open) if an aneurysm keeps on expanding. That is an emergency situation and life-threatening.


Abdominal aortic aneurysms usually don't cause any noticeable symptoms. A larger aneurysm can cause pain in your back or belly, or pain in your side.

If the abdominal aorta ruptures, it causes sudden back pain that radiates to the side or groin. A large amount of blood is lost quickly, causing sudden dizziness, loss of consciousness and eventually circulatory collapse.


An abdominal aortic aneurysm may arise if the blood vessel wall becomes less elastic, for example due to smoking – or if there is too much pressure on the blood vessel, for instance due to high blood pressure. The body's normal aging processes can also increase the risk. If one part of the vessel wall starts bulging, it tends to continue to expand, and then the aneurysm gets bigger.

Illustration: Aorta and bulging vessel wall (aneurysm) – as described in the article

Risk factors

There are a number of factors that can increase someone's risk of developing an abdominal aortic aneurysm.

  • Sex: Abdominal aortic aneurysms are more common in men than in women.
  • Age: The risk increases with age. Most people who have an abdominal aortic aneurysm are over 65 years old.
  • Smoking: Smoking is the biggest risk factor that you can influence yourself.
  • High blood pressure or coronary artery disease: People who have high blood pressure or coronary artery disease are more likely to develop an aneurysm.
  • Blood lipids: High levels of blood lipids (blood fats) increase the likelihood of an aneurysm developing.
  • Genes: The risk is also greater in people who have lighter skin or close relatives who have an abdominal aortic aneurysm.


About 2% of all men between the ages of 65 and 75 have an abdominal aortic aneurysm. Women are much less likely to have one. The number increases with age.


If an aneurysm gets bigger, it usually does so only gradually. But most aneurysms never cause any noticeable symptoms, and don't cause any problems for the rest of that person's life.

Only some aneurysms become so large that they are more likely to suddenly rupture (break open). If the aorta ruptures, a large amount of blood leaks into the abdominal cavity. This is a life-threatening emergency. The risk of an aneurysm rupturing is higher if the aneurysm is growing rapidly or if it's at least 5.5 cm (2.16 inches) in diameter. It is roughly estimated that aneurysms with a bigger diameter than that will rupture within one year in about 3 to 6 out of 100 men.


Abdominal aortic aneurysms are diagnosed using ultrasound scans of the abdomen (belly). The diameter of the abdominal aorta can be measured in this way. If the diameter of the aorta is greater than 3 cm (1.18 inches), it is considered to be an aneurysm.

If an aneurysm is causing noticeable symptoms, it is usually discovered when doctors try to find the cause.


Ultrasound scans can help discover large aneurysms early on. The aneurysm can then be operated on before it ruptures. If smaller bulges are found, they can be checked regularly to see whether they are growing, and how quickly.

Screening tests for men over the age of 65 reduce the risk of aneurysms rupturing and leading to death. But screening also has disadvantages: Some aneurysms are discovered and sometimes treated with surgery even though they never would have caused any problems. That is known as overdiagnosis. Also, the procedure itself may cause serious complications. Knowing that you have an aneurysm can be very distressing too.

There is only one high-quality study that looked into tests for women. It shows that doesn't have any advantages for women.


Whether or not treatment is a good idea, and what type of treatment would be suitable, will mainly depend on

  • the size of the aneurysm,
  • how it changes over time, and
  • your overall health.

Smaller abdominal aortic aneurysms that have a diameter of less than 5.5 cm (2.16 inches) are typically checked on a regular basis. If you smoke, your doctor will recommend that you quit because smoking increases the likelihood that the aneurysm will grow. People who have other risk factors, such as high blood pressure or high blood lipid levels, are advised to seek treatment for those conditions. But it is not yet clear whether medication to lower blood pressure or cholesterol can slow the growth of the aneurysm and actually reduce the risk of rupture.

If the risk of rupture is high, surgery is the only preventive measure. There are two types of surgery for a large aneurysm:

  • Open surgery through an abdominal incision (cut): The aneurysm is opened, and replaced with an artificial blood vessel (graft).
  • Endovascular procedure through a small cut in the groin: A small tube (stent) is put into the artery, pushed along to where the aneurysm is, and implanted in the aneurysm.

Both of these procedures are associated with risks. Determining whether surgery is a good idea is a very personal decision: The treatment involves risks such as lung complications, heart damage and stroke – but the aneurysm might rupture if left untreated.


Open surgery on the abdominal aorta is a major procedure. So the surgery is often followed by rehabilitative therapy. The goal of rehabilitation is to minimize the negative effects of the surgery and improve quality of life. Rehabilitation makes it possible to slowly get back to activities of everyday life so that it's easier to return to your normal routine.

Everyday life

Being diagnosed with an abdominal aortic aneurysm can stir up a lot of mixed feelings. Some people are happy that their aneurysm was discovered, and the check-ups help them to feel safe.

Others would rather have not found out about the aneurysm. Knowing about it can be scary and troubling. Many people who are diagnosed with an aneurysm constantly feel like their lives are in danger. Symptoms like a stomach ache may then be frightening: They are often thought to be related to the aneurysm, even if that's not actually the case. Many people stop doing certain things in everyday life out of fear that the aneurysm could rupture. They become more cautious and avoid physical exertion.

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IQWiG health information is written with the aim of helping people understand the advantages and disadvantages of the main treatment options and health care services.

Because IQWiG is a German institute, some of the information provided here is specific to the German health care system. The suitability of any of the described options in an individual case can be determined by talking to a doctor. informedhealth.org can provide support for talks with doctors and other medical professionals, but cannot replace them. We do not offer individual consultations.

Our information is based on the results of good-quality studies. It is written by a team of health care professionals, scientists and editors, and reviewed by external experts. You can find a detailed description of how our health information is produced and updated in our methods.

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Updated on October 6, 2021

Next planned update: 2024


Institute for Quality and Efficiency in Health Care (IQWiG, Germany)

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