Abdominal aortic aneurysm (AAA)

An abdominal aortic aneurysm (AAA) is a bulge that forms in a weakened section of the aorta as it passes through the abdomen. Many people have no abdominal aortic aneurysm symptoms until it grows large or causes complications, which is why AAA screening is important for those at risk. With regular monitoring and the right treatment plan, most people with an abdominal aortic aneurysm can manage the condition safely.

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Medical diagram showing an abdominal aortic aneurysm and comparison with a normal aorta.

Anatomy of the abdominal aorta

The aorta is the largest artery in the body. It carries oxygen-rich blood from your heart down through your chest and abdomen to the rest of your body. As it passes through the abdomen, the aorta supplies blood to your organs, including your kidneys and intestines, before branching into the arteries that reach your legs.

An abdominal aortic aneurysm develops when part of the aortic wall in this section weakens and stretches outward, forming a bulge. Over time, this bulge can enlarge, which increases the risk that the vessel wall could tear or rupture.

Overview

Symptoms

Many people with an abdominal aortic aneurysm have no symptoms at all, especially when the aneurysm is small. When symptoms do occur, they may include:

A pulsing feeling near the navel
Deep, constant pain in the abdomen or side
Back pain
In cases of rupture, sudden and severe abdominal or back pain, rapid heart rate, dizziness or fainting

A sudden increase in pain, especially paired with dizziness or a rapid pulse, can signal a medical emergency and needs immediate attention.

Causes

An abdominal aortic aneurysm develops when the wall of the aorta weakens, allowing it to stretch and bulge. The exact cause isn't always clear, but several factors are commonly associated with this weakening, including:

Hardening of the arteries (atherosclerosis), which can weaken the aortic wall over time
High blood pressure, which puts added stress on the vessel wall
Inflammation or infection affecting the aorta
In rare cases, injury to the abdomen

Risk factors

Certain factors can increase the likelihood of developing an abdominal aortic aneurysm, though having one or more of these doesn't mean you'll develop this condition:

Age older than 65
Being male
Smoking or long-term tobacco use
A family history of aortic aneurysms
High blood pressure or high cholesterol
Existing hardening of the arteries

Knowing your risk factors can help you and your care team decide whether AAA screening makes sense for you, including an abdominal ultrasound if you're eligible.

Diagnosis

An abdominal aortic aneurysm is often found during an exam or imaging test for an unrelated reason, since it typically doesn't cause symptoms in its early stages. If your care team suspects an aneurysm, they may recommend one of the following tests:

Ultrasound, which uses sound waves to measure the size of the aorta
CT scan, which provides detailed cross-sectional images to assess the aneurysm's size and shape
MRI scan, which offers another detailed imaging option to evaluate the aorta

Regular imaging helps your care team track any changes in the aneurysm's size over time and determine when abdominal aortic aneurysm repair should be considered, including minimally invasive options such as Endovascular aneurysm repair (EVAR).

Medical illustration highlighting the aorta and major blood vessels throughout the body.

Understanding abdominal aortic aneurysm

Learn how an AAA forms, the symptoms to watch for, and why screening matters. See how our specialists diagnose and repair abdominal aneurysms with care you can trust.

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