Basic Facts

  • An aneurysm is an enlarged portion of a weak area of an artery. Over time, blood flow can cause the weak area to bulge like a balloon.
  • An abdominal aortic aneurysm (AAA) is an enlargement in the aorta, the main blood vessel that carries blood away from the heart. 
  • Abdominal aortic aneurysms can burst or rupture, causing serious internal bleeding and, if not treated, death.
  • The risk for complications increases with the size of the aneurysm. In general, larger abdominal aortic aneurysms should be considered for treatment while smaller aneurysms should be monitored carefully for any enlargement.

Larger aneurysms, more than two inches in diameter, are more likely to burst, resulting in internal bleeding that is fatal unless treated immediately. Only about half of patients with a ruptured AAA who get to a hospital survive.


Most people with AAA do not feel any symptoms, others may experience one or more of the following:

  • A rhythmic, pulsating feeling in the abdomen, similar to a heartbeat, or
  • Deep or severe pain in the abdomen or lower back.

A ruptured aneurysm normally causes severe abdominal or lower back pain and is life threatening, requiring immediate medical attention.

The cause of AAA is unclear. Some researchers believe that it may be associated with atherosclerosis, the buildup of cholesterol and fat (plaque) on the artery walls, or risk factors that contribute to atherosclerosis, such as high blood pressure and smoking.

High-risk populations include:

  • Men older than age 60,
  • People with high blood pressure,
  • Smokers,
  • People with chronic obstructive pulmonary disease, and
  • People with vascular diseases.

Aneurysms may also be genetic, or rarely, can be caused by trauma, connective tissue disease, or bacterial or fungal infections.

Physicians can only detect about 10 percent of AAAs during a physical examination. Most AAAs are diagnosed using imaging tests, including 

  • Abdominal ultrasonography, which uses sound waves to produces images of blood vessels in the abdomen, 
  • Computed tomography (CT) scans, which uses x-rays to produce detailed views of the blood vessels, and 
  • Magnetic resonance imaging (MRI), which uses magnetic and radio wave energy take pictures of blood vessels to show location and severity of aneurysms.

Aneurysms that are smaller than two inches in diameter and do not cause symptoms may be monitored regularly (approximately every six months). People with small aneurysms and high blood pressure may be given medication to lower their blood pressure.

Larger AAAs may require interventions such as:

  • Endovascular Stent Graft - A minimally invasive procedure, endovascular stent grafts allow a physician to implant a synthetic tube supported by metal into the aorta. The tube is threaded into the aorta using a catheter inserted through a small incision in the groin. The stent graft relieves pressure on the aneurysm wall. Following an endovascular stent graft, the aneurysm may eventually shrink.
  • Open Aneurysm Repair. Surgical repair involves opening the abdomen and replacing the weakened area of the aorta with a fabric tube.