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

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

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

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

When an abdominal aortic aneurysm ruptures, it is a true medical emergency. Aortic dissection occurs when the innermost lining of the artery tears and blood leaks into the wall of the artery. This most commonly occurs in the aorta within the chest.

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

The symptoms of rupture include:

• Abdominal mass
• Abdominal rigidity
• Anxiety
• Clammy skin
• Nausea and vomiting
• Pain in the abdomen or back -- severe, sudden, persistent, or constant. The pain may radiate to groin, buttocks, or legs.
• Pulsating sensation in the abdomen
• Rapid heart rate when rising to a standing position
• Shock

Your doctor will examine your abdomen. The exam also will include an evaluation of pulses and sensation in your legs.

Abdominal aortic aneurysm may be diagnosed with these tests:

• Abdominal ultrasound
• Angiography of aorta
• CT scan of abdomen

If the aneurysm is small and there are no symptoms (for example, if it was discovered during a routine physical), your doctor may recommend periodic evaluation. This usually includes a yearly ultrasound, to see if the aneurysm is getting bigger.

Aneurysms that cause symptoms usually require surgery to prevent complications.

Surgery is recommended for patients with aneurysms bigger than 5.5 cm in diameter and aneurysms that rapidly increase in size. 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 synthetic material, such as Dacron.
• The other approach is called endovascular stent grafting. An endovascular stent graft is a tube made of metal mesh that helps support the artery. Small, hollow tubes called catheters are inserted through arteries in your groin. The stent graft is sent through a catheter, and permanently placed into the artery. Endovascular stent grafting can be done without making a large cut in your abdomen, so you may get well faster. However, not all patients with abdominal aortic aneurysms can have this type of surgery.

The outcome is usually good if an experienced surgeon repairs the aneurysm before it ruptures. However, less than 40% of patients survive a ruptured abdominal aneurysm.

• Aortic dissection
• Aortic rupture
• Arterial embolism
• Heart attack
• Hypovolemic shock
• Kidney failure
• Stroke

Go to the emergency room or call 911 if you develop severe abdominal pain or any of the other symptoms of an aneurysm.

To reduce the risk of developing aneurysms:

• Avoid tobacco
• Eat well
• Exercise
• Get regular physical exams

Men over age 65 who have ever smoked should have a screening ultrasound performed once.

Isselbacher EM. Diseases of the aorta. In: Libby P, Bonow RO, mann DL, Zipes DP. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 8th ed. Philadelphia, Pa: Saunders Elsevier; 2007: chap 56.

Fleming C, Whitlock EP, Beil TL, Lederle FA. Screening for abdominal aortic aneurysm: a best-evidence systematic review for the U.S. Preventive Services Task Force. Ann Intern Med. 2005;142:203-211.

Hunt SA, Abraham WT, Chin, MH, Feldman AM, Francis GS, Ganiats TG, et al. ACC/AHA 2005 guideline update for the diagnosis and management of chronic heart failure in the adult. Circulation. 2005;112:1825-1852.