ABDOMINAL AORTIC ANEURYSMS

DEFINITION

An abdominal aortic aneurysm is an enlarged area in the lower part of the aorta, the major blood vessel that supplies blood to the body. The aorta, about the thickness of a garden hose, runs from your heart through the center of your chest and abdomen. Because the aorta is the body's main supplier of blood, a ruptured abdominalaortic aneurysm can cause life-threatening bleeding.

Depending on the size and rate at which your abdominal aortic aneurysm is growing, treatment may vary from watchful waiting to emergency surgery. Once an abdominal aortic aneurysm is found, doctors will closely monitor it so that surgery can be planned if it's necessary. Emergency surgery for a ruptured abdominal aortic aneurysm can be risky.

SYMPTOMS

Abdominal aortic aneurysm often grow slowly and usually without symptoms, making them difficult to detect. Some aneurysms will never rupture. Many start small and stay small, although many expand over time. Others expand quickly. Predicting how fast an abdominal aortic aneurysm may enlarge is difficult.

As an abdominal aoertic aneurysm enlarges, some people may notice:

A pulsating feeling near the navel
Deep, constant pain in your abdomen or on the side of your abdomen
Back pain

CAUSES

Most aortic aneurysms occur in the part of your aorta that's in your abdomen. Although the exact cause of abdominal aortic aneurysms is unknown, a number of factors may play a role, including:

Tobacco use. Cigarette smoking and other forms of tobacco use appear to increase your risk of aortic aneurysms. In addition to the damaging effects that smoking causes directly to the arteries, smoking contributes to the buildup of fatty plaques in your arteries (atherosclerosis) and high blood pressure. Smoking can also cause your aneurysm to grow faster by further damaging your aorta.
Hardening of the arteries (atherosclerosis).Atherosclerosis occurs when fat and other substances build up on the lining of a blood vessel, increasing your risk of an aneurysm.
Infection in the aorta (vasculities). In rare cases, abdominal aoertic aneurysms may be caused by an infection or inflammation that weakens a section of the aortic wall.

Aneurysms can develop anywhere along the aorta, but when they occur in the upper part of the aorta, they are called thoracic aortic aneurysms. More commonly, aneurysms form in the lower part of your aorta and are called abdominal aortic aneurysms. These aneurysms may also be referred to as AAA or triple A.

RISK FACTORS

Abdominal aoertic aneurysms risk factors include:

Age. Abdominal aortic aneurysms occur most often in people age 65 and older.
Tobacco use. Tobacco use is a strong risk factor for the development of an abdominal aortic aneurysms. The longer you've smoked or chewed tobacco, the greater your risk.
Atherosclerosis. Atherosclerosis, the buildup of fat and other substances that can damage the lining of a blood vessel, increases your risk of an aneurysm.
Being male. Men develop abdominal aortic aneurysm much more often than women do.
Family history. People who have a family history of abdominal aortic aneurysms are at increased risk of having the condition. People who have a family history of aneurysms tend to develop aneurysms at a younger age and are at higher risk of rupture.

COMPLICATIONS

Tears in the wall of the aorta (dissection) are the main complications of abdominal aoertic aneurysms. A ruptured aneursysm can lead to life-threatening internal bleeding. In general, the larger the aneurysm, the greater the risk of rupture.

Signs and symptoms that your aortic aneurysms has burst include:

Sudden, intense and persistent abdominal or back pain
Pain that radiates to your back or legs
Sweatiness
Clamminess
Dizziness
Nausea
Vomiting
Low blood pressure
Fast pulse
Loss of consciousness
Shortness of breath

Another complication of aortic aneurysms is the risk of blood clots. Small blood clots can develop in the area of the aortic aneurysms. If a blood clot breaks loose from the inside wall of an aneurysm and blocks a blood vessel elsewhere in your body, it can cause pain or block the blood flow to the legs, toes, kidneys or abdominal organs.

TESTS AND DIAGNOSIS

Abdominal aortic aneurysms are often found during an examination for another reason. For example, during a routine exam, your doctor may feel a pulsating bulge in your abdomen, though it's unlikely your doctor will be able to hear signs of an aneurysm through a stethoscope. Aortic aneurysms are often found during routine medical tests, such as a chest X-ray or ultrasound of the heart or abdomen, sometimes ordered for a different reason.

If your doctor suspects that you have an aortic aneurysm, specialized tests can confirm it. These tests might include:

Abdominal ultrasound. This exam can help diagnose an abdominal aortic aneurysm. During this painless exam, you lie on your back on an examination table and a small amount of warm gel is applied to your abdomen. The gel helps eliminate the formation of air pockets between your body and the instrument the technician uses to see your aorta, called a transducer. The technician presses the transducer against your skin over your abdomen, moving from one area to another. The transducer sends images to a computer screen that the technician monitors to check for a potential aneurysm.

Computerized tomography (CT) scan. This painless test can provide your doctor with clear images of your aorta. During a CT scan, you lie on a table inside a doughnut-shaped machine called a gantry. Detectors inside the gantry measure the radiation that has passed through your body and converts it into electrical signals. A computer gathers these signals and assigns them a color ranging from black to white, depending on signal intensity. The computer then assembles the images and displays them on a computer monitor.

Magnetic resonance imaging (MRI). MRI is another painless imaging test. Most MRI machines contain a large magnet shaped like a doughnut or tunnel. You lie on a movable table that slides into the tunnel. The magnetic field aligns atomic particles in some of your cells. When radio waves are broadcast toward these aligned particles, they produce signals that vary according to the type of tissue they are. Your doctor can use the images produced by the signals to see if you have an aneurysm.

Regular screening for people at risk of abdominal aortic aneurysm

The U.S. Preventive Services Task Force recommends that men ages 65 to 75 who have ever smoked should have a one-time screening for abdominal aortic aneurysm using abdominal ultrasound. People older than age 60 with a family history of abdominal aoertic aneurysm or other risk factors should talk with their doctors about whether to have a screening ultrasound.

TREATMENTS AND DRUGS

Here are the general guidelines for treating abdominal aortic aneurysm.

Small aneurysm

If you have a small abdominal aoertic aneurysm — about 1.6 inches, or 4 centimeters (cm), in diameter or smaller — and you have no symptoms, your doctor may suggest a watch-and-wait (observation) approach, rather than surgery. In general, surgery isn't needed for small aneurysm because the risk of surgery likely outweighs the risk of rupture.

If you choose this approach, your doctor will monitor your aneurysm with periodic ultrasounds, usually every six to 12 months and encourage you to report immediately if you start having abdominal tenderness or back pain — potential signs of a dissection.

Medium aneurysm

A medium aneurysm measures between 1.6 and 2.1 inches (4 and 5.3 cm). It's less clear how the risks of surgery versus waiting stack up in the case of a medium-size abdominal aortic aneurysm. You'll need to discuss the benefits and risks of waiting versus surgery and make a decision with your doctor. If you choose watchful waiting, you'll need to have an ultrasound every six to 12 months to monitor your aneurysm.

Large, fast-growing or leaking aneurysm

If you have an aneurysm that is large (larger than 2.2 inches, or 5.6 cm) or growing rapidly (grows more than 0.5 cm in six months), you'll probably need surgery. In addition, a leaking, tender or painful aneurysm requires treatment. There are two types of surgery for abdominal aortic aneurysm.

Open-abdominal surgery to repair an abdominal aortic aneurysm involves removing the damaged section of the aorta and replacing it with a synthetic tube (graft), which is sewn into place, through an open-abdominal approach. With this type of surgery, it will likely take you a month or more to fully recover.
Endovascular surgery is a less invasive procedure sometimes used to repair an aneurysm. Doctors attach a synthetic graft to the end of a thin tube (catheter) that's inserted through an artery in your leg and threaded up into your aorta. The graft — a woven tube covered by a metal mesh support — is placed at the site of the aneurysm and fastened in place with small hooks or pins. The graft reinforces the weakened section of the aorta to prevent rupture of the aneurysm.

Recovery time for people who have endovascular surgery is shorter than for people who have open-abdominal surgery. However, follow-up appointments are more frequent because endovascular grafts can leak. Follow-up ultrasounds are generally done every six months for the first year, and then once a year after that. Long-term survival rates are similar for both endovascular surgery and open surgery.

The options for treatment of your aneurysm will depend on a variety of factors, including location of the aneurysm, your age, kidney function and other conditions that may increase your risk of surgery or endovascular repair.

LIFESTYLE AND HOME REMEDIES

The best approach to prevent an aortic aneurysm is to keep your blood vessels as healthy as possible. That means taking these steps:

Quit smoking or chewing tobacco.
Keep your blood pressure under control.
Get regular exercise.
Reduce cholesterol and fat in your diet.

If you have some risk factors for aortic aneurysms, talk to your doctor. If you are at risk, your doctor may recommend additional measures, including medications to lower your blood pressure and relieve stress on weakened arteries.