Each year, more than 200,000 abdominal aortic aneurysms (AAAs) are diagnosed in the United States. AAAs are the 13th leading cause of deaths in the U.S., accounting for about 15,000 deaths annually.

Prominent people who died of a ruptured AAA include Albert Einstein, Lucille Ball, and George C. Scott. More AAAs are likely to be found in the future, now that screening for AAA was recently recommended for male smokers over the age of 55.

An AAA is a local enlargement or bulge in the abdominal portion of the aorta, the largest artery in the body. By definition, the enlargement is at least 50 percent larger than the size of the normal artery.

Though quite uncommon before age 60, the prevalence of AAA increases dramatically with age: AAAs are present in 4 percent to 9 percent of people over the age of 60. Most of these AAAs, however, are too small to be clinically important.

AAAs are four to five times more common in men than in women. They also occur more frequently in people with evidence of significant atherosclerosis, such as coronary artery or peripheral artery disease. Smoking is not only a major risk factor for the formation of an AAA but also speeds the rate of their enlargement. In addition, men whose brothers have an AAA are four to six times more likely to harbor an AAA themselves.

Although AAAs may cause abdominal or back pain in some, they usually produce no symptoms — until they rupture. Approximately 30 percent of asymptomatic AAAs are discovered when a routine physical examination reveals a pulsating mass above the belly button. Others may be detected as an unexpected finding when an abdominal ultrasound, CAT scan, or magnetic resonance imaging is performed for some other purpose.

But many AAAs go undetected until they rupture, most often with a fatal outcome. AAAs that produce pain or are tender during physical examination are more likely to rupture.

Since size strongly predicts the risk of rupture, repair is recommended when a large AAA is detected. Smaller AAAs are followed with repeated ultrasound examinations to determine any change in size, and repair is recommended if the rate of enlargement is rapid or if the bulge has ballooned to a dangerous size.

For many years, the only approach for repair of an AAA was open surgical replacement of the aneurysm with a graft. Over the past 15 years or so, another option, termed endovascular repair, has become more widely used.

This procedure involves inserting a fabric sleeve into the lumen (cavity) of the aneurysm. This sleeve, which is delivered through an incision made in a large artery (femoral artery) that supplies blood to the leg, keeps the blood from flowing directly through the AAA, thus greatly reducing the risk of rupture.

A recent study reported in the New England Journal of Medicine showed that nearly 5 percent of patients died after open-repair surgery, compared with only about 1 percent of those treated with the less-invasive endovascular repair.

Although the patients receiving endovascular repair were more likely to suffer a rupture than the surgical group during a four-year follow-up, their risk of rupture was still small and was offset by other complications that affected the open-surgery group.

Anatomical features limit the endovascular procedure to less than half of the people who need to have an AAA repaired. In addition, endovascular repair is more expensive than open repair, largely due to the cost of the graft itself, which ranges from $10,000 to $15,000.

Should you have an imaging procedure to check for an AAA? Probably not, unless you are a male smoker over the age of 55 or possibly a man or woman past age 70 with evidence of significant atherosclerosis.