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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 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 rupture (burst) or dissect. A 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 rupture and dissection often are fatal.

Overview

Most aneurysms occur in the aorta, the main artery that carries oxygen-rich blood from the heart to the body. The aorta goes through the chest and abdomen.

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

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

About 13,000 Americans die each year from aortic aneurysms. Most of the deaths result from rupture or dissection.

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

Outlook

Doctors often can successfully treat aortic aneurysms with medicines or surgery if they’re found in time. 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 Aneurysms

Aortic Aneurysms

The two types of aortic aneurysm are abdominal aortic aneurysm and thoracic aortic aneurysm. Some people have both types.

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, which is located below the arteries that supply blood to the kidneys.

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, which is located below the arteries that supply blood to the kidneys.

Abdominal Aortic Aneurysms

An aneurysm that occurs in the abdominal portion of the aorta is called an abdominal aortic aneurysm (AAA). Most aortic aneurysms are AAAs.

These aneurysms are found more often now than in the past because of computed tomography (to-MOG-rah-fee) scans, or CT scans, done for other medical problems.

Small AAAs rarely rupture. However, AAAs can grow very large without causing symptoms. Routine checkups and treatment for an AAA can help prevent growth and rupture.

Thoracic Aortic Aneurysms

An aneurysm that occurs in the chest portion of the aorta (above the diaphragm, a muscle that helps you breathe) is called a thoracic aortic aneurysm (TAA).

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

Aneurysms in the arteries of the brain are called cerebral (seh-RE-bral) 
aneurysms
or brain aneurysms. Brain aneurysms also are called berry aneurysms because they're often the size of a small berry.

Brain Aneurysm

The illustration shows a typical location of a brain aneurysm in the arteries that supply blood to the brain. The inset image shows a closeup view of the sac-like aneurysm.

The illustration shows a typical location of a brain aneurysm in the arteries that supply 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 (burst). A ruptured brain aneurysm can cause a stroke.

Peripheral Aneurysms

Aneurysms that occur in arteries other than the aorta and the brain arteries are called peripheral (peh-RIF-eh-ral) 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.

Many conditions and factors can damage and weaken the walls of the aorta and cause aortic aneurysms. Examples include aging, smoking, high blood pressure, and atherosclerosis (ath-er-o-skler-O-sis). Atherosclerosis is the hardening and narrowing of the arteries due to the buildup of a waxy substance 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).

A family history of aneurysms 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 of these conditions include Marfan syndrome, Loeys-Dietz syndrome, Ehlers-Danlos syndrome (the vascular type), and Turner syndrome.

These genetic 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 than other people. They’re also at higher risk for rupture and dissection.

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

Researchers continue to look for other causes of aortic aneurysms. For example, they’re looking for genetic mutations (changes in the genes) 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 factors include:

  • Male gender. Men are more likely than women to have aortic aneurysms.
  • Age. The risk for abdominal aortic aneurysms increases as you get older. These aneurysms are more likely to occur in people who are aged 65 or older.
  • Smoking. Smoking can damage and weaken the walls of the aorta.
  • A family history of aortic aneurysms. People who have family histories of aortic aneurysms are at higher risk for the condition, and they may have aneurysms before the age of 65.
  • A history of aneurysms in the arteries of the legs.
  • Certain diseases and conditions that weaken the walls of the aorta. Examples include high blood pressure and atherosclerosis.

Having a bicuspid aortic valve can raise the risk of having a thoracic aortic aneurysm. A bicuspid aortic valve has two leaflets instead of the typical three.

Car accidents or trauma also can injure the arteries and increase the risk for aneurysms.

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




What Are the Signs and Symptoms of an Aneurysm?

The signs and symptoms of an aortic aneurysm depend on the type and location of the aneurysm. Signs and symptoms also depend on whether the aneurysm has ruptured (burst) 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 body parts, or block blood flow.

Abdominal Aortic Aneurysms

Most abdominal aortic aneurysms (AAAs) develop slowly over years. They often don't cause 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 may include sudden, severe pain in your lower abdomen and back; nausea (feeling sick to your stomach) and vomiting; constipation and problems with urination; clammy, sweaty skin; light-headedness; and a rapid heart rate when standing up.

Internal bleeding from a ruptured AAA can send you into shock. Shock is a life-threatening condition in which blood pressure drops so low that the brain, kidneys, and other vital organs can't get enough blood to work well. Shock can be fatal if it’s not treated right away.

Thoracic Aortic Aneurysms

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

  • Pain in your jaw, neck, back, or chest 
  • Coughing and/or hoarseness
  • Shortness of breath and/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, sharp or stabbing 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.

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 an 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 (burst) 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 does surgery on the heart, lungs, and other organs and structures in the chest, including the aorta. A vascular surgeon does surgery on the aorta and other blood vessels, except those of the heart and brain.

Diagnostic Tests and Procedures

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

Ultrasound and Echocardiography

Ultrasound and echocardiography (echo) are simple, painless tests that use sound waves to create pictures of the structures inside your body. These tests can show the size of an aortic aneurysm, if one is found.

Computed Tomography Scan

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

During the test, your doctor will inject dye into a vein in your arm. The dye makes your arteries, including your aorta, visible on the CT scan pictures.

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 pictures than an ultrasound or echo.

Magnetic Resonance Imaging

Magnetic resonance imaging (MRI) uses magnets and radio waves to create pictures of the organs and structures in your body. This test works well for detecting aneurysms and pinpointing their size and exact location.

Angiography

Angiography (an-jee-OG-ra-fee) is a test that uses dye and special x rays to show the insides of your arteries. This test shows the amount of damage and blockage in blood vessels.

Aortic angiography shows the inside of your aorta. The test may show the location and size of an aortic aneurysm.




How Is an Aneurysm Treated?

Aortic aneurysms are treated with medicines and surgery. Small aneurysms that are found early and aren’t causing symptoms may not need treatment. Other aneurysms need to be treated.

The goals of treatment may include:

  • Preventing the aneurysm from growing
  • Preventing or reversing damage to other body structures
  • Preventing or treating a rupture or dissection
  • Allowing you to continue doing your normal daily activities

Treatment for an aortic aneurysm is based on its size. 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) is 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 lower the risk that the aneurysm will rupture (burst). 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 is at 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. This surgery involves a major incision (cut) in the abdomen or chest.

General anesthesia (AN-es-THE-ze-ah) is used during this procedure. The term “anesthesia” refers to a loss of feeling and awareness. General anesthesia temporarily puts you to sleep.

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

If needed, repair of the aortic heart valve also may be done during open abdominal or open chest surgery.

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. Surgeons do this type of surgery using catheters (tubes) inserted into the arteries; it doesn't require surgically opening the chest or abdomen. General anesthesia is used during this procedure.

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. This helps prevent the aneurysm from rupturing.

Endovascular Repair

The illustration shows the placement of a 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.

The illustration shows the placement of a 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.

The recovery time for endovascular repair is less than the recovery time for open abdominal or open chest repair. However, doctors can’t repair all aortic aneurysms with endovascular repair. The location or size of an aneurysm may prevent the use of a stent graft.




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 aortic aneurysm risk factors, but lifestyle changes can help you lower some risks.

For example, if you smoke, try to quit. Talk with your doctor about programs and products that can help you quit smoking. Also, try to avoid secondhand smoke. For more information about how to quit smoking, go to the Health Topics Smoking and Your Heart article.

Another important lifestyle change is following a healthy diet. 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 about following a healthy diet, go to 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.

Be as physically active as you can. Talk with your doctor about the amounts and types of physical activity that are safe for you. For more information about physical activity, go to the Health Topics Physical Activity and Your Heart article and the NHLBI’s "Your Guide to Physical Activity and Your Heart."

Work with your doctor to control medical conditions such as high blood pressure and high blood cholesterol. Follow your treatment plans and take all of your medicines as your doctor prescribes.

Screening for Aneurysms

Although you may not be able to prevent an aneurysm, early diagnosis and treatment can help prevent rupture and dissection.

Aneurysms can develop and grow large before causing any signs or symptoms. Thus, people who are at high risk for aneurysms may benefit from early, routine screening.

Your doctor may recommend routine screening if you’re:

  • A man between the ages of 65 and 75 who has ever smoked
  • A man or woman between the ages of 65 and 75 who has a family history of aneurysms

If you’re at risk, but not in one of these high-risk groups, ask your doctor whether screening will benefit you.




Living With an Aneurysm

If you have an aortic aneurysm, following your treatment plan and having ongoing medical care are important. Early diagnosis and treatment can help prevent rupture and dissection.

Your doctor may advise you to avoid heavy lifting or physical exertion. If your job requires heavy lifting, you may be advised to change jobs.

Also, try to avoid emotional crises. Strong emotions can cause blood pressure to rise, which increases the risk of rupture or dissection. Call your doctor if an emotional crisis occurs.

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

If you have a small aneurysm that isn’t causing pain, you may not need treatment. However, aneurysms can develop and grow large before causing any symptoms. Thus, people who are at high risk for aneurysms may benefit from early, routine screening.




Clinical Trials

The National Heart, Lung, and Blood Institute (NHLBI) is strongly committed to supporting research aimed at preventing and treating heart, lung, and blood diseases and conditions and sleep disorders.

NHLBI-supported research has led to many advances in medical knowledge and care. For example, this research has uncovered some of the causes of various diseases and conditions, as well as ways to prevent, diagnose, or treat them.

The NHLBI continues to support research aimed at learning more about various diseases and conditions, including aneurysms. For example, the NHLBI currently is supporting a study on exercise therapy and aneurysms. The study’s goal is to find out whether exercise can limit the growth of small abdominal aortic aneurysms in older adults.

Ongoing research often depends on the willingness of volunteers to take part in clinical trials. Clinical trials test new ways to prevent, diagnose, or treat various diseases and conditions.

For example, new treatments for a disease or condition (such as medicines, medical devices, surgeries, or procedures) are tested in volunteers who have the illness. Testing shows whether a treatment is safe and effective in humans before it is made available for widespread use.

By taking part in a clinical trial, you can gain access to new treatments before they’re widely available. You also will have the support of a team of health care providers, who will likely monitor your health closely. Even if you don’t directly benefit from the results of a clinical trial, the information gathered can help others and add to scientific knowledge.

If you volunteer for a clinical trial, the research will be explained to you in detail. You’ll learn about treatments and tests you may receive, and the benefits and risks they may pose. You’ll also be given a chance to ask questions about the research. This process is called informed consent.

If you agree to take part in the trial, you’ll be asked to sign an informed consent form. This form is not a contract. You have the right to withdraw from a study at any time, for any reason. Also, you have the right to learn about new risks or findings that emerge during the trial.

For more information about clinical trials related to aneurysms, talk with your doctor. You also can visit the following Web sites to learn more about clinical research and to search for clinical trials:




Links to Other Information About Aneurysms

Non-NHLBI Resources

Clinical Trials

 
April 01, 2011 Last Updated Icon

The NHLBI updates Health Topics articles on a biennial cycle based on a thorough review of research findings and new literature. The articles also are updated as needed if important new research is published. The date on each Health Topics article reflects when the content was originally posted or last revised.

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