ABDOMINAL AORTIC ANEURYSM

Most aneurysms occur in the aorta. The aorta is the main artery that carries blood from the heart to the rest of the body. The aorta comes out from the left ventricle of the heart and travels through the chest and abdomen.

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

An aortic aneurysm that occurs in the part of the aorta running through the abdomen is an abdominal aortic aneurysm. Three in four aortic aneurysms are AAAs.

An AAA can grow very large without producing symptoms. About 1 in 5 AAAs rupture.

Most abdominal aortic aneurysms (AAAs) develop slowly over years and have no signs or symptoms until (or if) they rupture. Sometimes, a doctor can feel a pulsating mass while examining a patient's abdomen. When symptoms are present, they can include:

• Deep penetrating pain in your back or the side of your abdomen
• Steady gnawing pain in your abdomen that lasts for hours or days at a time
• Coldness, numbness, or tingling in your feet due to blocked blood flow in your legs

If an AAA ruptures, symptoms can include sudden, severe pain in your lower abdomen and back; nausea 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. Shock is a life-threatening condition in which the organs of the body do not get enough blood flow.

Diagnosis

An aneurysm may be found by chance during a routine physical exam. More often, an aneurysm is found by chance during an x-ray, ultrasound, or computed tomography (CT) scan performed for another reason, such as chest or abdominal pain.

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

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.

Treatment

Experts recommend that men who have ever smoked (at least 100 cigarettes in their lifetime) and are between the ages of 65 and 75 should have an ultrasound screening to check for abdominal aortic aneurysms.

Treatment recommendations for aortic aneurysms are based on the size of the aneurysm. Small aneurysms found early can be treated with �watchful waiting.�

• If the diameter of the aorta is small�less than 3 centimeters (cm)�and there are no symptoms, �watchful waiting� and a followup screening in 5 to 10 years may be all that is needed, as determined by the doctor.

• If the aorta is between 3 and 4 cm in diameter, the patient should return to the doctor every year for an ultrasound to see if the aneurysm has grown.

• If the aorta is between 4 and 4.5 cm, testing should be repeated every 6 months.

• If the aorta is larger than 5 cm (2 inches around or about the size of a lemon) or growing more than 1 cm per year, surgery should be considered as soon as possible.

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

The traditional and most common type of surgery for aortic aneurysms is open abdominal or open chest repair. It involves a major incision in the abdomen or chest. General anesthesia is needed with this procedure.

The aneurysm is removed and the section of aorta is replaced with an artificial graft made of material such as Dacron� or Teflon�. The surgery takes 3 to 6 hours, and the patient remains 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. Open abdominal and chest surgeries have been performed for 50 years. More than 90 percent of patients make a full recovery.

In endovascular repair, the aneurysm is not removed, but a graft is inserted into the aorta to strengthen it. This type of surgery is performed through catheters (tubes) inserted into the arteries; it does not require surgically opening the chest or abdomen.

To perform endovascular repair, the doctor first inserts a catheter into an artery in the groin (upper thigh) and threads it up to the area of the aneurysm. Then, watching on x-ray, 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.

Placement of an endovascular stent graft in an aortic aneurysm: a catheter is inserted into an artery in the groin (upper thigh). It is then threaded up to the abdominal aorta, and the stent graft is released from the catheter. The stent graft allows blood to flow through the aneurysm.

Endovascular repair surgery reduces recovery time to a few days and greatly reduces time in the hospital. The procedure has been used since 1999. Not all aortic aneurysms can be repaired with this procedure. The exact location or size of the aneurysm may prevent the stent graft from being safely or reliably positioned inside the aneurysm.