What Is an Aneurysm?

An aneurysm is a section of blood vessel that is larger than it is supposed to be. They can happen all over your body in lots of different blood vessels. How doctors monitor and treat them depends on their size and their location.

What Is the Aorta?

The aorta is the main blood vessel in your body. It starts in your chest where it comes off your heart and sends branches to your arms and head. It travels through your chest and then enters your abdomen.

There are two main branches of the aorta that give blood to our liver, stomach, and intestines. There is another branch that delivers blood to each kidney. After the kidney branches come off, there is normally a fairly straight part of the aorta before it divides into two branches to supply blood to our legs. The straight section of the aorta before it divides is the most common place in our bodies for an aneurysm to develop.

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What Is an Abdominal Aortic Aneurysm?

The normal size of the aorta in our abdomen ranges from 1.7 cm to 2.5 cm depending on if you are a man or woman. That is around the size of a US nickel. Doctors diagnose an aneurysm when your aorta is larger than 3 cm in diameter, which is about the size of a silver half-dollar.

If you are diagnosed with an AAA, doctors will consider your aorta's size, your symptoms, and your overall health before deciding on the best treatment for you.

Why Is It a Problem?

As your blood vessel stretches and gets bigger, it grows thinner. Sometimes the growth itself can cause abdominal pain. Many patients get a CT scan after having abdominal pain, but a CT scan may not show anything unusual. 

At a certain size (or diameter), your aorta has a higher chance of leaking. A leaking aorta is always considered an emergency. We recommend aneurysms get fixed before they get too big.

Fortunately, heart doctors have studied thousands and thousands of aortic aneurysms, so we have a lot of information about how fast they grow and what the risks of leaking are at the different sizes.

How is AAA Diagnosed?

The most common way that doctors diagnose abdominal aortic aneurysms or “triple As” is when a patient has a CT scan for another health problem. In other words, they are usually found on accident.

Some people have a higher chance of developing AAAs. These people can get a screening ultrasound to look for an aneurysm. People who have a higher chance of developing an AAA include:

  • men over the age of 65 who have smoked at least 100 cigarettes in their lifetime, and
  • people who have a family member with an abdominal aortic aneurysm.

Next Steps & Treatment

Once you are diagnosed with a “triple A,” the next step is for your doctor to monitor (watch) your aneurysm to learn how fast it is growing. Doctors can usually monitor your aneurysm by giving you an ultrasound each year.

Most aneurysms grow less than 5 mm a year. Depending on the size of your aneurysm, your doctor may monitor it for many years.

If your aneurysm gets larger and may need to be repaired, your doctor will usually switch to CT scans to monitor your aneurysm. CT scans give doctors more detailed information about your aneurysm and can help doctors plan how to repair it.

How & When Do AAAs Get Fixed?

Once your aneurysm is larger than 5 cm in a woman or 5.5 cm in a man (about the size of the short side of a credit card) it's time to plan on fixing it. Just like people come in all different shapes and sizes, so do aneurysms.

The shape and location of your aneurysm plays a big role in the different options for repair. The goal of fixing an aneurysm is to re-route the blood flow going through it so there's no longer any pressure on the thin wall of your aorta. Doctors can do this in two different ways.

One way to fix an aneurysm is to perform a surgery where doctors sew in a new blood vessel, usually made of material, to replace the enlarged area. If you have this procedure, you will likely need to stay in the ICU for at least one to two nights in and in the hospital for over a week. 


A second way to fix an aneurysm is to travel inside the blood vessels and re-line the enlarged area with an endograft. An endograft is a combination of material and a metal framework to hold your blood vessel in place. Doctors can usually perform an endograft without making any incisions (cuts), and most patients can go home the day after the surgery.