What Is an Aneurysm?

An aneurysm (AN-u-rism) is a balloon-like bulge in an artery. Arteries are blood vessels that carry oxygen-rich blood from your heart to your body.

Arteries have thick walls to withstand normal blood pressure. However, certain medical problems, genetic conditions, and trauma can damage or injure artery walls. The force of blood pushing against the weakened or injured walls can cause an aneurysm.

An aneurysm can grow large and burst (rupture) or cause a dissection. Rupture causes dangerous bleeding inside the body. A dissection is a split in one or more layers of the artery wall. The split causes bleeding into and along the layers of the artery wall.

Both conditions are often fatal.

Overview

Most aneurysms occur in the aorta—the main artery that carries blood from the heart to the rest of the body. The aorta goes through the chest and abdomen.

An aneurysm that occurs in the part of the aorta that's in the chest is called a thoracic (tho-RAS-ik) aortic aneurysm. An aneurysm that occurs in the part of the aorta that's in the abdomen is called an abdominal aortic aneurysm.

Aneurysms also can occur in other arteries, but these types of aneurysm are less common. This article will focus on aortic aneurysms.

About 14,000 Americans die each year from aortic aneurysms. Most of the deaths result from rupture or dissection.

Early diagnosis and medical treatment can help prevent many cases of rupture and dissection. However, aneurysms can develop and become large before causing any symptoms. Thus, people who are at high risk for aneurysms can benefit from early, routine screening.

Outlook

When found in time, aortic aneurysms often can be successfully treated with medicines or surgery. Medicines may be given to lower blood pressure, relax blood vessels, and reduce the risk of rupture.

Large aortic aneurysms often can be repaired with surgery. During surgery, the weak or damaged portion of the aorta is replaced or reinforced.

Types of Aneurysm

Aortic Aneurysms

The two types of aortic aneurysm are abdominal aortic aneurysm (AAA) and thoracic aortic aneurysm (TAA).

Aortic Aneurysms

Figure A shows a normal aorta. Figure B shows a thoracic aortic aneurysm (which is located behind the heart). Figure C shows an abdominal aortic aneurysm located below the arteries that supply blood to the kidneys.

Abdominal Aortic Aneurysms

An aneurysm that occurs in the part of the aorta that's located in the abdomen is called an abdominal aortic aneurysm. AAAs account for 3 in 4 aortic aneurysms. They're found more often now than in the past because of computed tomography (to-MOG-rah-fee), or CT, scans done for other medical problems.

Small AAAs rarely rupture. However, an AAA can grow very large without causing symptoms. Thus, routine checkups and treatment for an AAA are important to prevent growth and rupture.

Thoracic Aortic Aneurysms

An aneurysm that occurs in the part of the aorta that's located in the chest and above the diaphragm is called a thoracic aortic aneurysm. TAAs account for 1 in 4 aortic aneurysms.

TAAs don't always cause symptoms, even when they're large. Only half of all people who have TAAs notice any symptoms. TAAs are found more often now than in the past because of chest CT scans done for other medical problems.

With a common type of TAA, the walls of the aorta weaken, and a section close to the heart enlarges. As a result, the valve between the heart and the aorta can't close properly. This allows blood to leak back into the heart.

A less common type of TAA can develop in the upper back, away from the heart. A TAA in this location may result from an injury to the chest, such as from a car crash.

Other Types of Aneurysms

Brain Aneurysms

When an aneurysm occurs in an artery in the brain, it's called a cerebral (seh-RE-bral or SER-eh-bral) aneurysm or brain aneurysm. Brain aneurysms also are sometimes called berry aneurysms because they're often the size of a small berry.

Brain Aneurysm

The illustration shows a typical location of a brain (berry) aneurysm in the arteries supplying blood to the brain. The inset image shows a closeup view of the sac-like aneurysm.

Most brain aneurysms cause no symptoms until they become large, begin to leak blood, or rupture. A ruptured brain aneurysm causes a stroke.

Peripheral Aneurysms

Aneurysms that occur in arteries other than the aorta and the brain arteries are called peripheral aneurysms. Common locations for peripheral aneurysms include the popliteal (pop-li-TE-al), femoral (FEM-o-ral), and carotid (ka-ROT-id) arteries.

The popliteal arteries run down the back of the thighs, behind the knees. The femoral arteries are the main arteries in the groin. The carotid arteries are the two main arteries on each side of your neck.

Peripheral aneurysms aren’t as likely to rupture or dissect as aortic aneurysms. However, blood clots can form in peripheral aneurysms. If a blood clot breaks away from the aneurysm, it can block blood flow through the artery.

If a peripheral aneurysm is large, it can press on a nearby nerve or vein and cause pain, numbness, or swelling.

Other Names for Aneurysm

• Abdominal aortic aneurysm
• Aortic aneurysm
• Berry aneurysm
• Brain aneurysm
• Cerebral aneurysm
• Peripheral aneurysm
• Thoracic aortic aneurysm

What Causes an Aneurysm?

The force of blood pushing against the walls of an artery combined with damage or injury to the artery’s walls can cause an aneurysm.

A number of factors can damage and weaken the walls of the aorta and cause aortic aneurysms.

Aging, smoking, high blood pressure, and atherosclerosis (ath-er-o-skler-O-sis) are all factors that can damage or weaken the walls of the aorta. Atherosclerosis is the hardening and narrowing of the arteries due to the buildup of a fatty material called plaque (plak).

Rarely, infections, such as untreated syphilis (a sexually transmitted infection), can cause aortic aneurysms. Aortic aneurysms also can occur as a result of diseases that inflame the blood vessels, such as vasculitis (vas-kyu-LI-tis).

Family history also may play a role in causing aortic aneurysms.

In addition to the factors above, certain genetic conditions may cause thoracic aortic aneurysms (TAAs). Examples include Marfan syndrome, Loeys-Dietz syndrome, and Ehlers-Danlos syndrome (the vascular type).

These conditions can weaken the body’s connective tissues and damage the aorta. People who have these conditions tend to develop aneurysms at a younger age and are at higher risk for rupture or dissection.

Trauma, such as a car accident, also can damage the aorta walls and lead to TAAs.

Researchers continue to look for other causes of aortic aneurysms. For example, they’re looking for genetic mutations that may contribute to or cause aneurysms.

Who Is At Risk for an Aneurysm?

Certain factors put you at higher risk for an aortic aneurysm. These include:

• Male gender. Men are more likely than women to have abdominal aortic aneurysms (AAAs)—the most common type of aneurysm.
• Age. The risk for AAAs increases as you get older. These aneurysms are more likely to occur in people who are 65 or older.
• Smoking. Smoking can damage and weaken the walls of the aorta.
• Family history of aortic aneurysm. People who have family histories of aortic aneurysm are at higher risk of having one, and they may have aneurysms before the age of 65.
• Certain diseases and conditions that weaken the walls of the aorta. For more information, see "What Causes an Aneurysm?"

Car accidents or trauma also can injure the arteries and increase your risk for an aneurysm.

If you have any of these risk factors, talk with your doctor about whether you need to be screened for aneurysms.

What Are the Signs and Symptoms of an Aneurysm?

The signs and symptoms of an aortic aneurysm depend on the type of aneurysm, its location, and whether it has ruptured or is affecting other parts of the body.

Aneurysms can develop and grow for years without causing any signs or symptoms. They often don't cause signs or symptoms until they rupture, grow large enough to press on nearby parts of the body, or block blood flow.

Abdominal Aortic Aneurysms

Most abdominal aortic aneurysms (AAAs) develop slowly over years. They often don't have signs or symptoms unless they rupture. If you have an AAA, your doctor may feel a throbbing mass while checking your abdomen.

When symptoms are present, they can include:

• A throbbing feeling in the abdomen
• Deep pain in your back or the side of your abdomen
• Steady, gnawing pain in your abdomen that lasts for hours or days

If an AAA ruptures, symptoms can include sudden, severe pain in your lower abdomen and back; nausea (feeling sick to your stomach) and vomiting; clammy, sweaty skin; lightheadedness; and a rapid heart rate when standing up.

Internal bleeding from a ruptured AAA can send you into shock. This is a life-threatening situation that requires emergency treatment.

Thoracic Aortic Aneurysms

A thoracic aortic aneurysm (TAA) may not cause symptoms until it dissects or grows large. Then, symptoms may include:

• Pain in your jaw, neck, back, or chest
• Coughing, hoarseness, or trouble breathing or swallowing

A dissection is a split in one or more layers of the artery wall. The split causes bleeding into and along the layers of the artery wall.

If a TAA ruptures or dissects, you may feel sudden, severe pain starting in your upper back and moving down into your abdomen. You may have pain in your chest and arms, and you can quickly go into shock. Shock is a life-threatening condition in which the body’s organs don’t get enough blood flow.

If you have any symptoms of TAA or aortic dissection, call 9–1–1. If left untreated, these conditions may lead to organ damage or death.

How Is an Aneurysm Diagnosed?

If you have aortic aneurysm, but no symptoms, your doctor may find it by chance during a routine physical exam. More often, doctors find aneurysms during tests done for other reasons, such as chest or abdominal pain.

If you have an abdominal aortic aneurysm (AAA), your doctor may feel a throbbing mass in your abdomen. A rapidly growing aneurysm about to rupture can be tender and very painful when pressed. If you're overweight or obese, it may be hard for your doctor to feel even a large AAA.

If you have an AAA, your doctor may hear rushing blood flow instead of the normal whooshing sound when listening to your abdomen with a stethoscope.

Specialists Involved

Your primary care doctor may refer you to a cardiothoracic or vascular surgeon for diagnosis and treatment of an aortic aneurysm.

A cardiothoracic surgeon performs surgery on the heart, lungs, and other organs and structures in the chest, including the aorta. A vascular surgeon performs surgery on the aorta and other blood vessels, except those of the heart and brain.

Diagnostic Tests and Procedures

To diagnose and evaluate an aneurysm, your doctor may recommend one or more of the following tests.

Ultrasound

This simple, painless test uses sound waves to create pictures of the structures inside your body. Ultrasound shows the size of an aneurysm, if one is found.

Computed Tomography Scan

A computed tomography (CT) scan is a painless test that uses x rays to take clear, detailed pictures of your internal organs.

During the test, your doctor will inject a special dye into a vein in your arm. This dye highlights the aorta on the CT scan images.

Your doctor may recommend this test if he or she thinks you have an AAA or a thoracic aortic aneurysm (TAA). A CT scan can show the size and shape of an aneurysm. This test provides more detailed images than an ultrasound.

Magnetic Resonance Imaging

Magnetic resonance imaging (MRI) uses magnets and radio waves to create images of the organs and structures in your body. This test is very accurate at detecting aneurysms and pinpointing their size and exact location.

Angiography

Angiography (an-jee-OG-ra-fee) uses a special dye injected into the bloodstream to highlight the insides of arteries on x-ray pictures. An angiogram shows the amount of damage and blockage in blood vessels.

An angiogram of the aorta is called an aortogram. An aortogram may show the location and size of an aortic aneurysm.

How Is an Aneurysm Treated?

Aortic aneurysms are treated with medicines and surgery. A small aneurysm that's found early and isn't causing symptoms may not need treatment. Other aneurysms need to be treated.

The goals of treatment are to:

• Prevent the aneurysm from growing
• Prevent or reverse damage to other body structures
• Prevent or treat a rupture or dissection
• Allow you to continue to do your normal daily activities

Treatment for aortic aneurysms is based on the size of the aneurysm. Your doctor may recommend routine testing to make sure an aneurysm isn't getting bigger. This method usually is used for aneurysms that are smaller than 5 centimeters (about 2 inches) across.

How often you need testing (for example, every few months or every year) will be based on the size of the aneurysm and how fast it's growing. The larger it is and the faster it's growing, the more often you may need to be checked.

Medicines

If you have an aortic aneurysm, your doctor may prescribe medicines before surgery or instead of surgery. Medicines are used to lower blood pressure, relax blood vessels, and reduce the risk of rupture. Beta blockers and calcium channel blockers are the medicines most commonly used.

Surgery

Your doctor may recommend surgery if your aneurysm is growing quickly or if it reaches a size linked with an increased risk of rupture or dissection.

The two main types of surgery to repair aortic aneurysms are open abdominal or open chest repair and endovascular repair.

Open Abdominal or Open Chest Repair

The standard and most common type of surgery for aortic aneurysms is open abdominal or open chest repair. It involves a major incision (cut) in the abdomen or chest. General anesthesia is used for this procedure—that is, you will be temporarily put to sleep so you don't feel pain during the surgery.

The aneurysm is removed, and the section of aorta is replaced with a graft made of material such as Dacron^® or Teflon.^® The surgery takes 3 to 6 hours, and you will remain in the hospital for 5 to 8 days.

It often takes a month to recover from open abdominal or open chest surgery and return to full activity. Most patients make a full recovery.

Endovascular Repair

In endovascular repair, the aneurysm isn't removed. Instead, a graft is inserted into the aorta to strengthen it. This type of surgery is done using catheters (tubes) inserted into the arteries; it doesn't require surgically opening the chest or abdomen.

The surgeon first inserts a catheter into an artery in the groin (upper thigh) and threads it to the aneurysm. Then, using an x ray to see the artery, the surgeon threads the graft (also called a stent graft) into the aorta to the aneurysm.

The graft is then expanded inside the aorta and fastened in place to form a stable channel for blood flow. The graft reinforces the weakened section of the aorta to prevent the aneurysm from rupturing.

Endovascular Repair

The illustration shows the placement of an endovascular stent graft in an aortic aneurysm. In figure A, a catheter is inserted into an artery in the groin (upper thigh). The catheter is threaded to the abdominal aorta, and the stent graft is released from the catheter. In figure B, the stent graft allows blood to flow through the aneurysm.

Endovascular repair reduces recovery time to a few days and greatly reduces time in the hospital. However, doctors can’t repair all aortic aneurysms with this procedure. The location or size of the aneurysm may prevent a stent graft from being safely or reliably placed inside the aneurysm.

How Can an Aneurysm Be Prevented?

The best way to prevent an aortic aneurysm is to avoid the factors that put you at higher risk for one. You can’t control all of the risk factors for aortic aneurysm, but lifestyle changes can help you reduce some risks.

Lifestyle changes include quitting smoking and controlling conditions such as high blood pressure and high blood cholesterol.

Talk to your doctor about programs and products that can help you quit smoking. Also try to avoid secondhand smoke.

Follow a healthy diet and be as physically active as you can. A healthy diet includes a variety of fruits, vegetables, and whole grains.

It also includes lean meats, poultry, fish, beans, and fat-free or low-fat milk or milk products. A healthy diet is low in saturated fat, trans fat, cholesterol, sodium (salt), and added sugar.

For more information on following a healthy diet, see the National Heart, Lung, and Blood Institute’s (NHLBI’s) Aim for a Healthy Weight Web site, "Your Guide to a Healthy Heart," and "Your Guide to Lowering Your Blood Pressure With DASH." All of these resources include general information about healthy eating.

Talk to your doctor about the amounts and types of physical activity that are safe for you. For more information on physical activity, see the Diseases and Conditions Index Physical Activity and Your Heart article and NHLBI’s "Your Guide to Physical Activity and Your Heart."

Follow your treatment plans for any other medical conditions you have. Take all of your medicines as prescribed.

Living With an Aneurysm

If you have an aortic aneurysm, it’s important to follow your treatment plan and have ongoing medical care. Early diagnosis and treatment help prevent many cases of rupture and dissection.

Aneurysms can develop and become large before causing any symptoms. Thus, people who are at high risk for aneurysms may need routine screening to find and monitor an aneurysm.

If you have a small aneurysm that isn’t causing pain, you may not need treatment. However, you may need routine tests to make sure the aneurysm isn’t getting bigger.

Your doctor may prescribe medicines to treat your aneurysm. Medicines can lower your blood pressure, relax your blood vessels, and reduce the risk of rupture. Take all of your medicines exactly as your doctor prescribes.

Key Points

• An aneurysm is a balloon-like bulge in an artery. Arteries are blood vessels that carry oxygen-rich blood from your heart to your body.
• Arteries have thick walls to withstand normal blood pressure. However, certain medical problems, genetic conditions, and trauma can damage or injure artery walls. The force of blood pushing against the weakened or injured walls can cause an aneurysm.
• An aneurysm can grow large and burst (rupture) or cause a dissection. Rupture causes dangerous bleeding inside the body. A dissection is a split in one or more layers of the artery wall. The split causes bleeding into and along the layers of the artery wall. Both conditions are often fatal.
• Most aneurysms occur in the aorta—the main artery that carries blood from the heart to the rest of the body. The aorta goes through the chest and abdomen.
• An aneurysm that occurs in the part of the aorta that's in the chest is called a thoracic aortic aneurysm (TAA). An aneurysm that occurs in the part of the aorta in the abdomen is called an abdominal aortic aneurysm (AAA). Aneurysms also can occur in other arteries, but these types of aneurysm are less common.
• A number of factors can damage and weaken the walls of the aorta and cause aortic aneurysms. Examples include aging, smoking, high blood pressure, atherosclerosis, infections, certain genetic conditions, and trauma. Family history also may play a role in causing aortic aneurysms.
• The signs and symptoms of an aortic aneurysm depend on the type of aneurysm, its location, and whether it has ruptured or is affecting other parts of the body. Aneurysms can develop and grow for years without causing signs or symptoms.
• Your doctor may find an aortic aneurysm by chance during a routine physical exam. More often, doctors find aneurysms during tests done for other reasons, such as chest or abdominal pain. To diagnose and evaluate an aneurysm, your doctor may recommend one or more tests.
• Aortic aneurysms are treated with medicines and surgery. A small aneurysm that's found early and isn't causing symptoms may not need treatment. Every aneurysm should be evaluated.
• Your doctor may prescribe medicines before surgery or instead of surgery. He or she may recommend surgery if your aneurysm is growing quickly or if it reaches a size linked with an increased risk of rupture or dissection.
• The best way to prevent an aneurysm is to avoid the factors that put you at higher risk for one. You can't control all of the risk factors for aneurysm, but lifestyle changes can help you reduce your risks. Examples of lifestyle changes include following a healthy diet, doing physical activity, not smoking, and treating other medical conditions such as high blood pressure and high blood cholesterol.
• If you have an aortic aneurysm, it's important to follow your treatment plan and have ongoing medical care. Early diagnosis and treatment help prevent many cases of rupture and dissection.

Links to Other Information About Aneurysm

Non-NHLBI Resources

• Aortic Aneurysm (MedlinePlus)
• Aneurysm (MedlinePlus)

Clinical Trials

• Current Research (ClinicalTrials.gov)