An abdominal aortic aneurysm (AAA) happens when the body’s largest artery, the aorta, becomes enlarged. The aorta comes directly out of the heart and runs down the back side of the abdomen. That’s why they are called abdominal aortic aneurysms.

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.

Abdominal aortic aneurysms are about 4 times more common in men than in women. And they are more likely to happen in smokers and ex-smokers. Also, the risk of an aneurysm goes up with age.

When an aneurysm ruptures, it can be fatal. Ideally, doctors want to use an ultrasound to find aneurysms and track any changes in size before this happens.

The risk of rupture depends on the size of the aneurysm. Doctors order ultrasounds every 6–12 months to see if they are getting larger. This helps them decide when surgery is needed.

Experts have studied thousands of patients. They have determined that the risk of rupture begins to outweigh the risk of treatment when an abdominal aneurysm is wider than 5–5.5 centimeters (a little more than 2 inches). Or when it expands by more than 1 centimeter (a little less than half an inch) in one year.

At 4.8 centimeters, your husband’s aneurysm is getting close — but its not there yet.