What Is It?

An abdominal aortic aneurysm is a potentially fatal abnormal swelling (often balloon-like) of a segment of the body's largest artery, the aorta. The side wall of the artery bulges out rather than remaining straight.

The aorta carries oxygen-rich blood from the heart to smaller arteries throughout the body. An abdominal aneurysm occurs in the abdominal aorta, the part of the aorta between the bottom of the chest and the pelvis.

Normally, the aorta is about one inch (2.5 centimeters) in diameter. The size increases very gradually as people age. If the abdominal section of the aorta becomes larger than 3 centimeters, the person is said to have an abdominal aortic aneurysm.

Abdominal aortic aneurysms are most common in people 60 and older. They affect about 5% to 7% of people in this age group living in the United States. Although about 20% of people with abdominal aortic aneurysms have a close relative with the same problem, no clear genetic link has been found. The family connection seems to be particularly strong among brothers.

Most aortic aneurysms are related to atherosclerosis, a condition in which fatty deposits called plaque build up along the inside walls of blood vessels. This is the same condition that contributes to coronary artery disease in the heart and stroke in the brain.

Symptoms

Most aortic aneurysms don't cause any symptoms. Aneurysms often are discovered during routine physical exams or during X-rays for unrelated illnesses. When symptoms develop, they can include:

• Pain in the abdomen, back or the fleshy part of your sides between the bottom of your ribs and your hips

• A feeling of fullness after eating a small meal

• Nausea and vomiting

• A pulsating mass in the abdomen

Rarely, floating blood clots (thrombi) can form near the aneurysm. These clots can break away and block blood vessels elsewhere in the body, causing symptoms of poor blood flow wherever they become stuck.

In about 20% of cases, an undiscovered abdominal aneurysm ruptures without warning, and the patient collapses and dies from massive bleeding inside the abdomen.