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Abdominal Aortic Aneurysm

An aneurysm is a weak section of an artery wall. Pressure from inside the artery causes the weakened area to bulge out beyond the normal width of the blood vessel. An abdominal aortic aneurysm is an aneurysm in the lower part of the aorta, the large artery that runs through the torso.

Abdominal Aortic Aneurysm: What You Need to Know

Location of the aorta in the body
Click image to enlarge
  • Abdominal aortic aneurysm is sometimes known as AAA, or triple A.

  • Older, long-term smokers are at especially high risk for abdominal aortic aneurysm.

  • Many people have no symptoms and don’t know they have an aortic aneurysm until it ruptures, which is often quickly fatal.

  • Symptoms, when they do occur, include pain in the back or near the naval. An extremely sharp and severe pain may indicate rupture, requiring emergency medical treatment.

  • Smaller, slow-growing aortic aneurysms may be treated with watchful waiting, lifestyle changes and medication. Large or fast-growing aortic aneurysms may require surgery.

What is the abdominal aorta?

The abdominal aorta is one section of your largest blood vessel. The abdominal section starts just below the ribcage and extends down to feed the kidneys, stomach and other organs, then branches off to feed the legs.

What are the types of abdominal aortic aneurysms?

Abdominal aortic aneurysms are classified by shape and location.

Abdominal Aortic Aneurysm Shapes

Different types of aortic aneurysms
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The more common shape is fusiform, which balloons out on all sides of the aorta. A bulging artery isn’t classified as a true aneurysm until it increases the artery’s width by 50 percent.

A saccular shape is a bulge in just one spot on the aorta. Sometimes this is called a pseudoaneurysm. It usually means the inner layer of the artery wall is torn, which can be caused by an injury or ulcer in the artery.

Abdominal Aortic Aneurysm Locations

  • Infrarenal abdominal aortic aneurysm (infrarenal AAA): below the kidneys. This is the most common type of AAA.

  • Suprarenal abdominal aortic aneurysm (suprarenal AAA): at or above the kidneys.

  • Thoracoabdominal aortic aneurysm: extending from the abdominal aorta, all the way up through the ribcage and into the upper (thoracic) aorta.

What are the dangers of an abdominal aortic aneurysm?

The chief danger is rupture, which is usually fatal.

Once a part of the aortic wall weakens, the force of blood pumped from the heart can stretch the wall into an aneurysm. If it ruptures, blood pumping from the heart causes hemorrhaging (fast and heavy bleeding) into the abdomen. Only about half of the people who suffer a ruptured aneurysm live long enough to get to the hospital.

The larger the aneurysm or the faster it grows, the greater the risk of rupture. Preventing rupture of an aneurysm is one of the goals of treatment.

Dissection is also a danger. Sometimes, a tear can occur on the inside layer of the aorta, resulting in blood seeping in among the layers of the artery wall and creating a dissecting aortic aneurysm or aortic dissection.

What are the symptoms of an abdominal aortic aneurysm?

About 75 percent of abdominal aortic aneurysms occur without any symptoms and may rupture before anyone knows they exist. Symptoms that do occur may resemble other medical conditions. Always consult your doctor for more information if you experience these symptoms:

  • Pain. May be located in the abdomen, chest, lower back or groin. Pain may be dull or severe. Younger people are more likely to have pain as a symptom than older people.

    By the time it occurs, pain can signal a coming rupture. Acute (sudden and severe) pain in the back and/or abdomen may mean an aneurysm has already ruptured. This is a life-threatening medical emergency.

  • Lack of blood flow to the legs. Sometimes, an aneurysm presses against other blood vessels, slowing blood flow to the legs. This is called limb ischemia.

  • Back pain. The aneurysm may press against nerves in the torso, causing back pain.

What causes an abdominal aortic aneurysm?

The precise cause isn’t fully known, but multiple risk factors may result in the breakdown of connective tissue and muscle that form the artery’s three strong, flexible walls.

Risk Factors

Atherosclerosis — a buildup of plaque, which is a deposit of fat, cholesterol, cellular waste products, calcium and tough threads of fibrin that can line an artery — is thought to play an important role in aneurysms. Therefore, the following risk factors for atherosclerosis are also risk factors for abdominal aortic aneurysm:

  • Smoking: the most common risk factor for aneurysms. All smokers over 65 should be screened for abdominal aortic aneurysm. Risk goes up the longer you’ve smoked and goes down the longer you haven’t.

  • Age: over 60

  • Men: four to five times more likely to have an aneurysm, though large aneurysms in women are more likely to rupture.

  • Family history: a first-degree relative (immediate family member) who’s had an aortic aneurysm

  • Hyperlipidemia: too much “bad” cholesterol

  • Hypertension: high blood pressure

  • Diabetes: in artery walls damaged by high blood sugar, where plaque easily sticks

  • Obesity: due to a rise in other risk factors such as hypertension, hyperlipidemia, and diabetes

  • Race: more common among whites.

  • Other vascular disease

Other diseases that may cause an abdominal aneurysm include:

  • Genetic disorders of connective tissue: abnormalities that can affect tissues, such as bones, cartilage, heart and blood vessels; examples include Marfan syndrome, Ehlers-Danlos syndrome, Turner syndrome and polycystic kidney disease

  • Congenital (present at birth) syndromes, such as bicuspid aortic valve or coarctation of the aorta

  • Giant cell arteritis: a disease that causes inflammation and narrowing of the temporal arteries and other arteries in the head and neck, reducing blood flow in the affected areas; may cause persistent headaches and vision loss

  • Trauma to the abdomen

  • Infectious aortitis: infections of the aorta due to diseases such as syphilis, salmonella or staphylococcus; infectious aortitis is rare

  • Other aneurysm: especially an iliac aneurysm, located in the iliac arteries that descend from the bottom of the aorta into the legs. More than 80 percent of people with an iliac aneurysm will develop an abdominal aortic aneurysm.

How are abdominal aortic aneurysms diagnosed?

Incidental Diagnosis

Because three-fourths of abdominal aortic aneurysms have no symptoms, they are often diagnosed when tests are done for other reasons, such as a medical imaging study or a workup for claudication or peripheral artery disease (PAD).

A physician may feel a pulsing mass under the skin during a physical exam. This is harder to sense if the person is obese.

Diagnostic Tests

In addition to a complete medical history and physical exam, diagnostic procedures for an aneurysm may include some combination of the following:

  • Computed tomography (CT or CAT) scan: A combination of X-rays and computer technology that can show detailed images of any part of the body, including the bones, muscles, fat and organs, CT scans are more detailed than general X-rays and can show when an AAA has ruptured or is about to rupture.

  • Magnetic resonance imaging (MRI): Uses large magnets and radio frequencies to produce detailed images of organs and structures within the body. An MRI is not an X-ray and does not produce radiation.

  • Ultrasound: High-frequency sound waves create images of blood vessels, tissues and organs; ultrasounds are used to view internal organs as they function and to assess blood flow through various vessels.

  • Angiogram (arteriogram): an X-ray image of the blood vessels used to evaluate various conditions, such as aneurysm, stenosis (narrowing of the blood vessel) or blockages; a dye, known as “contrast,” is injected into an artery to make the blood vessels visible on an X-ray.

How are abdominal aortic aneurysms treated?

Treatment depends on many factors, including the aneurysm’s size and rate of growth, the health of the patient, and the riskiness of open or minimally invasive surgery.

Watchful Waiting

Watchful waiting is the term physicians use for postponing surgery while they pursue other, less invasive treatments. It is often used if the aneurysm is small and slow growing, or if surgery is too risky.

During watchful waiting, the aneurysm will be closely monitored while medications and lifestyle changes attempt to slow the rate of growth. Some aneurysms never grow to a dangerous size.

Watchful waiting treatment may include:

  • Routine ultrasound procedures can be used to monitor the size and rate of growth of the aneurysm every six to 12 months for smaller aneurysms, which are less than 5 or 5.5 centimeters.

  • Controlling or modifying risk factors. Steps such as quitting smoking, controlling blood sugar if diabetic, losing weight if overweight or obese, and controlling dietary fat intake may help to slow the progression of the aneurysm.

  • Mild to moderate aerobic exercise can lower the risk of rupture. Speak to your doctor about what specific exercise will be beneficial and what to avoid.

  • Medication. Medication can control risk factors such as cholesterol and blood pressure.


Surgery may be necessary if the aneurysm is large or fast growing, increasing chances of rupture. Women with large aneurysms are more likely than men to suffer a rupture.

For suprarenal (above the kidneys) AAA, only open surgery is available in the U.S. right now, though Johns Hopkins vascular surgeons are involved in endovascular device trials that may be a suitable option. However, AAA at or below the kidneys may be treated by open or endovascular surgery. Endovascular means “within the blood vessel” and is considered minimally invasive.

Not all patients can tolerate the risk of open surgery, so endovascular repair is a great option. Unfortunately, not all patients have the anatomy to qualify for endovascular repair. Consult your vascular surgeon about which technique is best for you.

    Stent graft repair of abdominal aneurysm
    Click image to enlarge

    Minimally Invasive Surgery for Aortic Aneurysms | Q&A

    Johns Hopkins’ expert vascular surgeons can provide minimally-invasive aneurysm repair, with shorter hospital stays and quicker recovery. They even perform a hybrid surgery for those who aren’t eligible for the least invasive procedure but can’t have open surgery.

  • Open aneurysm repair: A large incision is made in the abdomen to repair the aneurysm. Another incision is made in the aorta for the length of the aneurysm. A cylinder called a graft is used for the repair. Grafts are made of polyester fabric or polytetrafluoroethylene (PTFE, nontextile synthetic graft). This graft is sewn to the aorta, from just above the aneurysm site to just below it. The artery walls are then sewn over the graft.

    Graft repair of abdominal aneurysm
    Click image to enlarge

Abdominal & Thoracic Aortic Aneurysm Treatment: Open Surgery | Q&A

If you need open repair for an abdominal aortic aneurysm, Johns Hopkins vascular surgeons have you covered. Learn more about it from Dr. James Black, expert in the most advanced vascular surgery.

  • Endovascular aneurysm repair (EVAR): A small incision is made in the groin. Using X-ray guidance, a stent graft is inserted into the femoral artery and sent to the site of the aneurysm. A stent is a thin metal mesh framework shaped into a long tube, while the graft, a fabric covering the mesh, is made of a polyester fabric called PTFE. The stent holds the graft open and in place.  EVAR is used only for an infrarenal (below the kidneys) AAA. It may be more easily tolerated by high-risk patients. However, the graft can sometimes slip out of place and may later need to be fixed.


    Fenestrated stent graft for abdominal aortic aneurysm
    Used by permission of Cook Medical, Inc.
  • Fenestrated stent graft: When the aneurysm is juxtarenal (at the kidneys) or involves the arteries of the kidneys, the prior standard treatment has been open surgery. That’s because a traditional stent graft has no openings to accommodate the branching of the aorta to the kidneys. In 2012, the FDA approved a fenestrated stent graft, now available in a few vascular surgery programs, including Johns Hopkins. The fenestrated stent graft is made to the precise size of each patient’s aorta so the openings for the renal (kidney) arteries are in just the right place to maintain kidney circulation.

Fenestrated Endovascular Aortic Aneurysm Repair | Q&A

For abdominal aortic aneurysms at or above the kidneys, open repair can lead to kidney failure. Johns Hopkins is one of the few hospitals to offer the minimally-invasive fenestrated stent graft surgery that preserves blood flow to the kidneys.

Reviewed by James Black, M.D. and Christopher Abularrage, M.D. of the Johns Hopkins Department of Vascular Surgery and Endovascular Therapy

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