Some patients may need fewer tests to keep track of a bulging artery, a new study suggests. The study focused on abdominal aortic aneurysm. This is a bulge in the aorta inside the belly area. If it ruptures (bursts), 8 out of 10 people die. Doctors order ultrasounds to keep track of when it's big enough to make surgery worthwhile. But there's no agreement on how often to do them. British researchers combined numbers from 18 previous studies. They came up with an ultrasound schedule that they estimated would result in only a 1% chance of rupture before the next test. They suggested tests every 2 years for aneurysms of 3.0 to 3.9 centimeters in diameter. This would increase to every year for 4.0 to 4.9 centimeters and every 6 months for 5.0 to 5.4 centimeters. That's not much different from current U.S. practice. But British doctors do the scans much more often. Study results apply only to men. Women are less likely to have these aneurysms than men. But in women the smaller ones are more likely to burst. The Journal of the American Medical Association published the study. HealthDay News wrote about it February 26.
By Howard LeWine, M.D.
Harvard Medical School
What Is the Doctor's Reaction?
The aorta comes directly out of the heart and runs down the back side of the abdomen. The part inside the belly is called the abdominal aorta. An abdominal aortic aneurysm happens when that part of the aorta enlarges.
An aneurysm is a bulge in an artery caused by a weak spot in the artery wall. It is usually the result of fatty deposits that build up and damage the artery wall.
Most often aneurysms don't cause any symptoms until they rupture (burst). But you don't want that to ever happen. Once an aneurysm breaks open, the risk of dying is high.
The size of an aneurysm is directly related to the risk of rupture. The bigger it is, the greater the risk. Ideally, doctors want to use an ultrasound test to find an aneurysm before it ruptures. The ultrasound can also measure its size.
The size of an aneurysm determines whether and when a procedure is needed to fix it. It can be done with either open surgery or another procedure called endovascular repair.
Doctors usually wait until the aneurysm reaches 5.5 centimeters in diameter before recommending surgery. That's a little more than 2 inches across. The reason for waiting is the risk level. For smaller aneurysms, the risks of surgery are higher than the risk of a rupture.
An abdominal aortic aneurysm is defined as enlargement of at least 3.0 centimeters. Once an aortic aneurysm is found, doctors order an ultrasound from time to time to see if it is getting bigger. There is no formal consensus on how often to repeat the ultrasound.
The results of this study support the current use of ultrasound monitoring by most doctors in the United States. In Great Britain, where the study was performed, doctors order them more often.
Based on their results, the authors suggest the following:
- 3.0 to 3.9 centimeters, repeat ultrasound every 2 years
- 4.0 to 4.9 centimeters, repeat ultrasound every 12 months
- 5.0 to 5.4 centimeters, repeat ultrasound every 6 months
What Changes Can I Make Now?
These numbers work well for men. And abdominal aortic aneurysms are about 4 times more common in men than in women. But women actually have a greater risk of rupture of smaller aneurysms.
There is not enough information about these aneurysms in women to advise how often to monitor size and when to do surgery. Although it's not tested or proven, perhaps more frequent monitoring could be done for a couple of years. This allows the doctor to see if the aneurysm is enlarging faster than expected.
If a woman has an aneurysm that reaches 4.5 centimeters, I refer her to a vascular surgeon. That doesn't mean a procedure always needs to be done right away. More frequent ultrasounds might be enough.
Other than being a man, the other major factor that increases the risk of developing one of these aneurysms is smoking, both past and present. The risk is high enough that male past and present smokers should get a one-time screening abdominal ultrasound. This should occur between ages 65 and 75. Women and nonsmoking men with a family history of abdominal aortic aneurysm should consider a screening ultrasound at age 65.
You can also reduce your risk of developing an aortic aneurysm by:
- Regular exercise
- Eating a healthy diet
- Keeping blood pressure in the normal range
- Lowering your LDL (bad) cholesterol if it is high
What Can I Expect Looking to the Future?
I suspect that the results of this study will lead to formal guidelines on how often to monitor the size of these aneurysms in men. More research will be needed before this can be done for women.