What Are The Causes And Treatments Of Aortic Aneurysms?

My mother has been told that she has a bubble in her aorta (aneurysm). Her doctor says he wants to monitor it rather than repair it. This concerns me greatly. I’ve heard that if it bursts the only way you can survive is if you are in a hospital. Do you think my mother should get a second opinion?

Aortic aneurysms can occur in several different locations and may have different causes. Since I don’t know the location or cause of your mother’s aneurysm, I will discuss aortic aneurysms in general.

The aorta is a strong tube that carries the blood from the heart to the rest of the body. Since the aorta receives the full force of each heartbeat, it has to be strong and flexible to withstand this persistent hammering. Anything that weakens the wall of the aorta, whether it be an infection, a degeneration of the tissues, or arteriosclerosis, can cause the aorta to enlarge. This enlargement is called an aneurysm.

In the days before antibiotics, the most common cause of aortic aneurysms was probably syphilis, which typically caused aneurysms to form close to the heart. These aneurysms did not usually rupture or burst, but the associated heart disease was often fatal.

People with some inherited diseases, Marfan’s syndrome, and type IV Ehler-Danlos syndrome tend to get a degeneration of the aortic wall, usually near the heart, which leads to an aneurysm. These aneurysms are quite likely to rupture and are always repaired if they exceed a certain size.

Nowadays the most common cause of aortic aneurysms is artherosclerosis. These aneurysms are usually found in the abdomen, where the aorta runs down from the chest into the pelvis and splits into two arteries, one going to each leg. These aneurysms often do not produce any symptoms and are found accidentally when a person is tested for some other condition or when they rupture.

As you mentioned in your letter, if an abdominal aortic aneurysm ruptures, the mortality rate is very high — at least 50 percent, even if surgery is done promptly. Therefore, it is always better to repair them before they rupture. The trick is in figuring out which ones are most likely to rupture, since the surgery is complicated and people with these aneurysms are often elderly and have other medical problems that make them poor surgical risks.

The normal abdominal aorta measures no more than 2 centimeters in diameter on ultrasound. Anything larger would be considered an aneurysm, but aneurysms smaller than 4 cm in diameter rarely rupture. A recent Mayo Clinic study reported no ruptures of aneurysms smaller than 4 centimeters; one percent per year for aneurysms 4-5 centimeters in diameter; and 11 percent per year for aneurysms 5-6 centimeters in diameter. Another text that I checked reported a slightly higher rupture rate of aneurysms larger than 4 centimeters.

So the decision to do surgery immediately or wait and watch the aneurysm depends on lots of factors, including the age, health, and surgical risk of the patient and the size of the aneurysm. The size can be measured accurately, but the evaluation of surgical risk can be tricky. I think you should try to discuss the size and risk issues with your mother’s doctor. Perhaps her aneurysm measures only 3 cm in diameter, in which case, the risk of rupture is small. Perhaps the doctor is worried that your mother’s heart disease makes the risk of surgery too great, even if the aneurysm measures 4.5 cm. Of course, seek a second opinion if the doctor’s explanation isn’t satisfactory.

A recent technique may permit surgery on people even at high risk. This involves placing a stent, a kind of brace, within the aorta through an incision in a leg artery. No abdominal surgery is required and the survival rates seem to be good. However, this technique is very new and is not widely available.

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