The aorta is the main artery that carries blood away from the heart to the rest of the body. The walls of the artery can bulge out if they become weak. When this happens in the part of the aorta that runs through the abdomen, it is called an abdominal aortic aneurysm.

An abdominal aortic aneurysm can occur without any symptoms, and it may not always require treatment. However, in some cases, treatment is necessary to prevent severe symptoms from occurring.

In this article, we discuss what an abdominal aortic aneurysm is and how to treat it.

An aneurysm occurs when the walls of an artery become weak. Pressure from inside the artery can build up and cause a weakened area of the artery wall to bulge outward. This bulge is an aneurysm.

An abdominal aortic aneurysm (AAA) is a bulge in the major artery — the aorta — that moves blood away from the heart to the rest of the body. It runs down through the torso, supplying blood to organs that include the liver and kidneys.

This blood vessel then divides in two and runs down to the legs. An AAA occurs in the section of the aorta just before it divides.

Some aneurysms may be harmless. However, some can rupture, leading to life threatening internal bleeding that can rapidly become fatal.

Doctors might class an AAA as either small, medium, or large to guide treatment.

Small AAAs are 3–4.4 centimeters (cm) in diameter. These aneurysms are unlikely to rupture and may not require treatment. A doctor will advise lifestyle changes to prevent a small aneurysm from growing.

Medium AAAs are 4.5–5.4 cm in diameter. In addition to recommending lifestyle changes, a doctor will likely monitor these aneurysms regularly to ensure that they are not growing.

Larger AAAs are greater than 5.5 cm in diameter and have a higher likelihood of rupturing. Doctors usually recommend surgery to stop these aneurysms from getting bigger or bursting.

A buildup of pressure in the artery and a weakening of the artery wall cause AAA.

The pressure might build up due to atherosclerosis. This disease causes plaque, which is a fatty substance in the blood, to gather inside the arteries.

As plaque gathers, it causes pressure to build up in the artery and can lead to an AAA developing.

In some cases, an AAA might occur as a part of an inherited condition. For example, some genes can increase the risk of an AAA. Certain inherited disorders, such as Marfan syndrome and Ehlers-Danlos syndrome, may increase the risk of AAA.

In other cases, an AAA may result from an injury, such as dissection, or an infection, such as syphilis.

People who are at a higher risk of developing an AAA include those who:

  • are male, white, and aged 65 or over
  • have a family history of AAA
  • have hypertension
  • smoke

Other risk factors may include prior vascular disease and hypercholesterolemia (high cholesterol).

As many aneurysms do not cause symptoms, they may not necessitate a trip to the doctor. Many AAAs show up when the doctor is screening for something else.

To screen for an AAA, a doctor will use medical imaging techniques, including:

  • Ultrasound: This procedure uses high frequency sound waves to measure the size of an AAA.
  • CT scan: In this scan, X-rays create a detailed picture of the AAA.
  • Angiography: This test involves X-rays, CT scans, or MRI scans and a special dye to detect abnormalities in blood vessels.

The Preventive Services Task Force recommend that men aged 65–75 who have ever smoked get an ultrasound screening for AAA, even if they have no symptoms.

Many AAAs, particularly smaller ones, will not cause any symptoms. When the aneurysm grows, symptoms are more likely. If the AAA ruptures, symptoms might include:

  • sharp and severe pain in the stomach or back
  • dizziness and confusion
  • nausea and vomiting
  • shortness of breath
  • low blood pressure and a rapid heart rate

The symptoms are usually severe and require immediate medical attention.

It is not always possible to prevent an AAA. For example, some genetic factors can increase the risk, as can aging.

However, living a healthful lifestyle will always be useful in preventing an AAA. Lifestyle measures that can help reduce a person’s risk include:

  • eating a healthful and balanced diet
  • exercising regularly
  • stopping smoking, if relevant
  • reaching and maintaining a moderate weight
  • reducing alcohol use

Smaller AAAs may not require any treatment, but a doctor may want to monitor the situation and check for signs of growth.

Doctors may also suggest lifestyle changes to reduce the risk of a rupture in people with small AAAs. For example, they may recommend stopping smoking or losing weight.

Larger AAAs usually require treatment, which may include surgery to repair the artery wall.

One such procedure, called endovascular aneurysm repair, involves passing a small device through cuts in the groin. The device helps protect the artery wall from possible ruptures. Doctors typically use this approach for people who are older and at higher risk of rupture.

Open surgery may be another option for AAA repair. This procedure involves an incision and the replacement of the diseased aorta with an artificial graft.

The main complication of an AAA is a rupture, which can cause internal bleeding and other severe symptoms.

Other complications of an AAA may include:

  • infections
  • fistulas
  • pseudoaneurysm
  • blood clots

Many AAAs will not cause any symptoms and might not require treatment. However, it is important to see a doctor for any signs of an aneurysm. A doctor will help determine the risk of rupture and monitor the situation.

Males who are 65 years of age or older and have ever smoked should get an ultrasound screening for AAA.

It is essential to seek immediate medical attention if the aneurysm causes any symptoms, including persistent and severe back or stomach pain.

The outlook for a person with an AAA will depend on its severity. It is possible to have an AAA for years without any symptoms. People with a known AAA may need to see a doctor for checkups every 6–12 months.

If treatment is necessary, the recovery period will typically include a few days in the hospital and up to 3 months of recovery time.

An abdominal aortic aneurysm is a bulge in the part of the aorta that is in the abdomen. In some cases, it causes no symptoms. Regular checkups may still be necessary, though.

In other cases, the AAA might become large enough to cause problems. Doctors may use surgery to treat the condition.

Without treatment, an AAA can rupture and cause severe symptoms.