An abdominal aortic aneurysm is when the large blood vessel (aorta) that supplies blood to the abdomen, pelvis, and legs becomes abnormally large or balloons outward.

Aneurysm - aortic; AAA

The exact cause is unknown, but risk factors for developing an abdominal aortic aneurysm include:

• Emphysema
• Genetic factors
• High blood pressure
• High cholesterol
• Male gender
• Obesity
• Smoking

An abdominal aortic aneurysm can develop in anyone, but is most often seen in males over age 60 who have one or more risk factors. The larger the aneurysm, the more likely it is to rupture and break open.

Aneurysms develop slowly over many years and often have no symptoms. If an aneurysm expands quickly, tears open (ruptures), or blood leaks along the wall of the vessel (aortic dissection), symptoms may develop suddenly.

The symptoms of rupture include:

• Pain in the abdomen or back -- severe, sudden, persistent, or constant. The pain may spread to the groin, buttocks, or legs
• Clammy skin
• Dizziness
• Nausea and vomiting
• Rapid heart rate
• Shock

Your doctor will examine your abdomen. The exam also will include an evaluation of pulses in your legs. The doctor may find:

• A lump (mass) in the abdomen
• Pulsating sensation in the abdomen
• Stiff or rigid abdomen

You may have an abdominal aortic aneurysm that is not causing any symptoms or problems. Your doctor may find this problem by doing the following tests:

• Angiogram
• CT scan of the abdomen -- to confirm the size of the aneurysm
• Ultrasound of the abdomen -- done when an abdominal aneurysm is first suspected

Any one of these tests may be done when you're having symptoms.

If you have bleeding inside your body from an aortic aneurysm, you will have open abdominal aortic aneurysm repair.

If the aneurysm is small and there are no symptoms:

• Surgery is rarely done if the aneurysm is small.
• You and your doctor must decide whether the risk of having surgery is smaller than the risk of bleeding if you do not have surgery.
• Your doctor may recommend checking the size of the aneurysm with ultrasound tests every 6 months to see if it is getting bigger.

Surgery is usually recommended for patients who have aneurysms bigger than 2 inches (5.5 cm) across and aneurysms that are growing quickly. The goal is to perform surgery before complications or symptoms develop.

There are two approaches to surgery:

• In a traditional (open) repair, a large cut is made in your abdomen. The abnormal vessel is replaced with a graft made of man-made material, such as Dacron.
• The other approach is called endovascular stent grafting. This procedure can be done without making a large cut in your abdomen, so you may get well faster. If you have certain other medical problems, this may be a safer approach. Endovascular repair is rarely done for a leaking or bleeding aneurysm.

The outcome is usually good if an experienced surgeon repairs the aneurysm before it ruptures.

When an abdominal aortic aneurysm begins to tear or ruptures, it is a true medical emergency. Less than 80% of patients survive a ruptured abdominal aneurysm.

Go to the emergency room or call 911 if you have pain in your belly or back that does not go away or is very bad.

To reduce the risk of developing aneurysms:

• Eat a heart-healthy diet, exercise, stop smoking (if you smoke), and reduce stress to help lower your chances of having a blocked artery again.
• Your health care provider may give you medicine to help lower your cholesterol.
• If you were given medicines for blood pressure or diabetes, take them as your doctor has asked you to.

People over age 65 who have smoked at any time in their life should have a screening ultrasound performed once.

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Greenhalgh RM, Powell JT. Endovascular repair of abdominal aortic aneurysm. N Engl J Med. 2008;358:494-501.

Lederle FA, Kane RL, MacDonald R, Wilt TJ. Systematic review: repair of unruptured abdominal aortic aneurysm. Ann Intern Med. 2007;146:735-741.

Braverman AC, Thompson RW, Sanchez LA. Diseases of the aorta. In: Bonow RO, Mann DL, Zipes DP, Libby P, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 9th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 60.