Cardiovascular Disease and Death in Older Adults with Small Aneurysm in the Abdominal Aorta

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The summary below is from the full report titled "Cardiovascular Disease and Mortality in Older Adults with Small Abdominal Aortic Aneurysms Detected by Ultrasonography: The Cardiovascular Health Study." It is in the 6 February 2001 issue of Annals of Internal Medicine (volume 134, pages 182-190). The authors are AB Newman, AM Arnold, GL Burke, DH O'Leary, and TA Manolio.

What is the problem and what is known about it so far?

The aorta, a large artery in the chest and the abdomen, is the main channel for carrying blood from the heart to the rest of the body. Abdominal aortic aneurysms are bulges that occur in weakened sections of the abdominal aorta. Aneurysms are more common in people with high blood pressure. Large aneurysms can burst, which often causes death. For this reason, it is generally recommended that patients with abdominal aortic aneurysms larger than about 2 inches across (5 cm) undergo an operation to replace the weakened section of the aorta. It is unknown whether people with small aneurysms are at higher risk for developing cardiovascular disease (such as heart attacks and strokes) and dying than are people without aneurysms.

Why did the researchers do this particular study?

To compare cardiovascular disease events and deaths in persons with and without small abdominal aortic aneurysm.

Who was studied?

The study included 4734 men and women older than 65 years of age who were recruited from lists of persons eligible for Medicare.

How was the study done?

The researchers performed an ultrasound test on all study participants. This test uses sound waves to create a picture of the aorta and is a good way to look for aneurysms. An aneurysm was defined as a bulge in the aorta that was at least 3 cm (slightly more than 1 inch) across. The researchers then followed participants for 4 and a half years to see who developed cardiovascular disease, required surgery to repair the aneurysm, had a burst aneurysm, or died.

What did the researchers find?

Of the 4734 study participants, 416 (8.8%) had an abdominal aortic aneurysm. More than 87% of these aneurysms were smaller than 3.5 cm across. Men, smokers, and people who were older or had known cardiovascular disease were most likely to have aneurysms. Twenty-three people (all of whom had aneurysms larger than 5 cm) required surgery for aneurysm repair, and six people died of burst aneurysms. Even after accounting for cardiovascular risk factors, such as smoking and abnormal cholesterol levels, persons with aneurysms were 40% more likely than those without aneurysms to develop cardiovascular events or die.

What were the limitations of the study?

The study could not determine whether screening for abdominal aortic aneurysms would decrease cardiovascular events and death or whether repair of small aneurysms would improve patients' outcomes.

What are the implications of the study?

Because persons with small abdominal aortic aneurysms appear to be at a higher risk for developing new cardiovascular disease or death, doctors should make extra efforts to advise these persons to modify risk factors for cardiovascular disease, such as smoking, high blood pressure, and unhealthy cholesterol levels.