Paging Dr. Frischer: Abdominal Aortic Aneurysm

AAA means one thing to a driver with a flat tire, but quite another to someone with a dilated aorta. 

If you are a man older than 50, you run roughly a 4-7% chance of having an abdominal aortic aneurysm (AAA), and if you are a woman over 50, your odds are closer to 1%.

The aorta is the largest artery in the body, and it carries oxygen-rich blood away from the heart and supplies it to the rest of the body. The problem with an aortic aneurysm is not simply that it is a swelling of the aorta, but that as it grows larger, the risk of the aorta rupturing becomes significant. 

Usually there will be no symptoms before it ruptures, and it may not be possible to have immediate emergency surgery in time to repair it. The risk for rupture depends on the size of the aneurysm, and if it does rupture, 75% to 90% of the time it is fatal. In the United States, ruptured AAA is estimated to cause 4-5% of all sudden deaths. Therefore, screening is critical for those at high risk.

Typically, an AAA is found when an exam is performed for another reason. A doctor may feel a pulsating bulge in the abdomen, or it might be detected through computed tomography (CT), magnetic resonance imaging (MRI), or abdominal ultrasound.

So, should we all be routinely screened? The answer is complicated. The majority of aneurysms never rupture. As the number of screenings increase, so will the number of previously undiagnosed small aneurysms that are unlikely to ever rupture. Elective surgery can prevent aneurysm rupture, but every surgery always carries with it some level of risk. And, since the patient who is most likely to have an AAA is older, the risk that
accompanies surgery is even greater. 

Surgical repair is typically considered an option only for aneurysms that have reached five and a half to six centimeters in size. Imagine knowing that you have an aneurysm of “only” five centimeters! Would it feel like a ticking time bomb? You can see how challenging those borderline cases can be.

Current recommendations suggest that men between the ages of 65 to 75 who have ever smoked cigarettes should have a one-time screening for abdominal aortic aneurysm, using abdominal ultrasound. In addition, men aged 60 and older with a family history of abdominal aortic aneurysm should consider regular screenings. 

On the other hand, the statistics don’t support screening of women smokers ages 65 to 75, or those with a family history. The reason is that when lower risk populations (such as women) are screened for AAA, they are twice as likely to undergo elective surgery within three to five years. While the risk of death from elective surgery is far lower than the risk of death from rupture, many of these elective surgeries are unnecessary, and pose needless risk.

The goal of treatment is to prevent a rupture. If the abdominal aortic aneurysm is too small to justify elective surgery, then it can be monitored. Monitoring would include annual x-rays, controlling blood pressure (which relieves the stress on weakened arteries), not smoking cigarettes, getting regular exercise, limiting alcohol, and eating a healthy diet. To regular readers of my columns, most of this list should look pretty familiar! 

Speak with your doctor about whether you are a candidate for screening.