What is an abdominal aortic aneurysm?

An abdominal aortic aneurysm (AAA) is an enlargement or bulge in the part of your aorta that extends through your belly or abdomen (abdominal aorta). The bulge forms in an area where your aorta’s wall has grown weak. Normally, your aorta’s wall is strong and flexible enough to manage the constant pressure of blood your heart pumps out. But various factors like aging, tobacco use and certain medical conditions can weaken your aorta’s wall. When the wall is weak, it can’t handle the forces of blood flow as well it should.

As a result, the weakened part of your aorta’s wall expands outward and enlarges. This expansion, or ballooning, continues to grow wider over time. Your healthcare provider will diagnose you with an AAA if a segment of your aorta expands to at least 50% of its normal diameter. For many people, this means the bulge is about 3 centimeters (cm) wide.

The larger an aneurysm grows, the more likely it is to burst open (rupture) and cause life-threatening internal bleeding. AAAs larger than 5.0 centimeters in females and 5.5 centimeters in males are particularly at risk. The larger they grow, the more dangerous they become. AAAs usually have no symptoms until they rupture or are close to rupturing. That’s why it’s essential to learn if you have risk factors for an AAA and work with a healthcare provider to manage them.

An AAA rupture is a medical emergency. Call 911 or your local emergency number if you have sudden, severe pain in your belly or lower back. Symptoms may also include shortness of breath, dizziness and nausea.

How common are abdominal aortic aneurysms?

Abdominal aortic aneurysms are a common condition.

• They occur in about 1.4% of adults between the ages of 50 and 84 in the U.S. This is around 1.1 million people.
• They occur in between 1% and 2% of males over age 65. With each additional decade of life the risk of developing an AAA doubles.
• They’re four times more common in males.
• They occur in about 1% of females over 70 with a history of smoking.

Research has also shown:

• Aneurysms can form anywhere along your aorta, but they usually form in your belly. Abdominal aortic aneurysms represent about 75% of all aortic aneurysms.
• AAAs are more common among white people compared to Black people and Asian people.
• AAAs most often affect people males. But when they form in females, they have a higher risk of rupturing at smaller sizes as well as occurring in family members.

What are the symptoms of an abdominal aortic aneurysm?

Most people with an AAA don’t have symptoms until the aneurysm is close to rupturing. At that point, you may have:

• Steady, deep pain in your lower back or belly.
• Pain in your leg, groin or pelvic area.
• A pulsing sensation in your belly that feels like a heartbeat.

A ruptured AAA is a medical emergency. Symptoms begin suddenly and can include:

• Severe pain in your belly, lower back or legs.
• Shortness of breath.
• Fast heartbeat.
• Low blood pressure.
• Dizziness or fainting.
• Nausea or vomiting.
• Clammy, sweaty skin.

Call 911 or your local emergency number if you have symptoms of an aneurysm rupture.

What causes an abdominal aortic aneurysm?

An underlying weakness in your aorta’s wall causes an AAA to form. Many environmental and hereditary factors come together to cause this weakness. Overall, the exact reason they form isn’t understood.

For example, tobacco use causes your aorta’s wall to lose proteins that provide its structure. This reduces its strength. Your aorta’s wall can also grow weaker due to plaque buildup (atherosclerosis). Plaque formation and growth over time can cause inflammation and cell death in the layers of the artery wall. As the building blocks of your aorta’s wall break down, your aorta grows weaker and more vulnerable to abnormal expansion.

What are the risk factors for abdominal aortic aneurysms?

These risk factors play the biggest role in determining who develops an AAA:

• History of tobacco use. Researchers define this as smoking at least 100 cigarettes during your lifetime. Your exact risk varies by use (the more you used tobacco, the higher your risk).
• Older age. You face a higher risk of an AAA as you get older (over age 50 for males, and over age 65 for females).
• Sex at birth. Males are more likely to develop an AAA.
• Family history of AAA. Family history plays an important role in the development of AAAs. About 10% to 20% of people who have a first-degree relative with an AAA also develop one. This means you face a higher risk if your biological parent, child or sibling had an AAA at some point in their life. The association is especially strong among male siblings.

Other risk factors that can play a role include:

• High blood pressure.
• Having some form of atherosclerotic cardiovascular disease (ASCVD). This includes coronary artery disease (CAD) and peripheral artery disease (PAD).
• Having an inherited vascular connective-tissue disease.

What are the complications of AAA?

The most common complication is an aneurysm rupture, which causes 150,000 to 200,000 deaths each year around the world. AAA rupture leads to potentially fatal internal bleeding. Your risk goes up the larger an aneurysm grows.

How is an abdominal aortic aneurysm diagnosed?

Since AAAs don’t usually cause symptoms, healthcare providers often diagnose unruptured AAAs through tests ordered for other health conditions. If your provider suspects you have an AAA due to test results or other reasons, they may perform:

• Abdominal duplex ultrasound.
• Computed tomography angiogram (CTA).

Screening for abdominal aortic aneurysms

Healthcare providers recommend an ultrasound screening for people at risk for an AAA. This imaging test is simple and painless and shows if you have an AAA. If you do, your provider will recommend additional ultrasounds at regular intervals (usually every six to 12 months) to monitor the aneurysm. If it grows too large or you have other risk factors for aneurysm rupture, your provider will recommend surgery.

What is the treatment for an abdominal aortic aneurysm?

Treatment depends on the size of the aneurysm, which is the main factor that determines its risk of rupturing. Small aneurysms may not need treatment right away. Instead, your provider will monitor the aneurysm through regular ultrasound tests or CT (computed tomography) scans. This approach is called surveillance. Larger aneurysms may need surgery.

Surveillance of AAAs

Surveillance is typically appropriate when the AAA has a diameter of less than 5.5 centimeters in males or less than 5.0 centimeters in females. The aneurysm also shouldn’t be causing any symptoms.

You’ll have an ultrasound or CT scan at regular intervals depending on the size of the aneurysm. Larger aneurysms need imaging more often. If you’re close to the treatment threshold, you may get CT scans and not ultrasounds. Be sure to follow your provider’s instructions on when you need your imaging tests. Your provider will also tell you:

• What lifestyle changes you should make. These include avoiding all tobacco use, eating a heart-healthy diet and exercising.
• Which medications you need to take to manage conditions like high blood pressure or high cholesterol.

Lifestyle changes and medications won’t shrink the aneurysm (currently there’s no treatment that can do this). But these measures may help slow aneurysm growth and lower your risk of other cardiovascular problems. Researchers continue to explore medications and other treatments that may limit or stop the growth of small AAAs.

Surgery for AAAs

You may need surgery for your AAA if:

• The aneurysm has a diameter of at least 5.5 centimeters (in females) or 5.0 centimeters (in males). Some centers of excellence may advise elective surgery at smaller diameters depending on your overall health, risk profile and other factors.
• The aneurysm is causing symptoms, no matter its size.
• The aneurysm has ruptured. In this case, you need immediate surgery to save your life.

Surgery lowers your risk for aneurysm rupture by replacing the aorta or relining the aorta from the inside with a new graft. There are two surgical methods available to do this:

• Traditional open aneurysm repair surgery.
• Endovascular aneurysm repair (EVAR).

Surgeons and patients generally prefer EVAR for elective surgery because it offers an easier recovery and a better short-term survival rate. When the anatomy is appropriate, an EVAR can provide a long-lasting repair. But you’ll need evaluation with ultrasound or CT scans of the repair on a yearly basis. Certain factors (like your age or anatomy) may make open surgery a safer option. Each method has benefits and risks. Your provider will discuss these with you, and together, you can reach a decision.

Ruptured aneurysms need immediate surgery to give you a chance at survival.

What can I expect if I have this condition?

Your outlook depends on many factors, including the size of the aneurysm, when you receive treatment and your overall health. Your healthcare provider is the best person to ask about what you can expect going forward. They know you and your unique medical history best.

Can I prevent an abdominal aortic aneurysm?

We have no known ways to prevent development of an AAA. Talk to your healthcare provider if your biological parent, sibling or child had an AAA. They may recommend an ultrasound screening to check for signs of aneurysm formation.

Whether or not you have a family history of AAA, you can take action to lower other risk factors and support your overall cardiovascular health. Talk to your provider about ways to:

• Quit smoking or other tobacco use.
• Develop an exercise plan that’s healthy for you.
• Follow a heart-healthy diet.
• Manage your blood pressure, cholesterol and blood sugar.
• Limit beverages containing alcohol.

How do I take care of myself?

If you have an AAA, it’s important to follow your provider’s guidance for taking care of yourself. They’ll tailor advice to your needs. In general, here are some tips:

• Go to all of your medical appointments and follow-ups.
• Make lifestyle changes to support your health. Start small and give yourself reasonable goals.
• Take your medications exactly as your provider prescribes them.
• Ask your provider if you need antibiotics before certain dental or medical procedures. This is necessary for some people following aneurysm repair surgery to prevent infections.

When should I see my healthcare provider?

Call your provider if you have:

• New or changing symptoms.
• Side effects from medications.
• Questions or concerns about your condition or your treatment plan.

Your provider will tell you how often you need to come in for appointments. You may need imaging tests at regular intervals to check:

• If an AAA is growing or at risk of rupturing.
• If there are complications from EVAR, such as endoleak, or signs of a possible re-rupture.

Be sure to go to all of your appointments so your provider can keep an eye on your condition and help you stay healthy.

When should I go to the emergency room?

Call 911 or your local emergency number if you have signs of an AAA rupture, including sudden and severe pain in your belly or lower back.

What questions should I ask my provider?

You may want to ask your provider:

• Am I at risk for an AAA?
• Do I need a screening for an AAA?
• What lifestyle changes should I make to lower my risk?

If your provider diagnosed you with an AAA, you can learn more by asking:

• How big is the aneurysm?
• Do you recommend surveillance or surgery?
• Which type of surgery is better for me?
• What are the benefits and risks of surgery?
• How long will recovery take?
• What follow-ups will I need after surgery?
• Should any of my family members have AAA screenings?