Canada Vascular

Aortic Aneurysms (TAA & AAA)

Diagnosis

Treatment Options

Glossary

Bibliography

 

 


Background

What is Abdominal Aortic Aneurysm (AAA)?

The aorta is the largest artery in your body,and it carries blood away from your heart. Your aorta runs through your chest, where it is called the thoracic aorta. When it reaches your abdomen, it is called the abdominal aorta. The abdominal aorta supplies blood to the lower part of the body. Just below the abdomen, the aorta splits into two branches that carry blood into each leg.

When a weak area of the abdominal aorta expands or bulges, it is called an abdominal aortic aneurysm (AAA). The pressure from blood flowing through your abdominal aorta can cause a weakened part of the aorta to bulge, much like a balloon. A normal aorta is about 2 centimeters in diameter. However, AAA can stretch the aorta beyond its safety margin.



In the past 30 years, the occurrence of Abdominal Aortic Aneurysms (AAA) has increased threefold. Most commonly, aortic aneurysms occur in the portion of the vessel below the renal artery origins. The aneurysm may extend into the vessels supplying the hips and pelvis.

Once an aneurysm reaches 5 cm in diameter, it is usually considered necessary to treat to prevent rupture. Below 5cm, the risk of the aneurysm rupturing is lower than the risk of conventional surgery in patients with normal surgical risks. The goal of therapy for aneurysms is to prevent them from rupturing. Once an abdominal aortic aneurysm has ruptured, the chances of survival are low, with 80 to 90 percent of all ruptured aneurysms resulting in death. These deaths can be avoided if an aneurysm is detected and treated before it ruptures.

AAA can cause another serious health problem. Clots or debris can form inside the aneurysm and travel to blood vessels leading to other organs in your body. If one of these blood vessels becomes blocked, it can cause severe pain or even more serious problems, such as limb loss.

How Common is AAA?

Each year, physicians diagnose approximately 20,000 people in Canada with AAA. Of those 20,000, nearly 2000 may have AAA threatening enough to cause death from a ruptured aneurysm if not treated.

  • Approximately one in every 250 people over the age of 50 will die of a ruptured AAA
  • AAA affects as many as eight percent of people over the age of 65
  • Males are four times more likely to have AAA than females9
  • AAA is the 17th leading cause of death in the United States, accounting for more than 15,000 deaths each year.
  • Those at highest risk are males over the age of 60 who have ever smoked and/or who have a history of atherosclerosis ("hardening of the arteries")
  • Those with a family history of AAA are at a higher risk (particularly if the relative with AAA was female)
  • Smokers die four times more often from ruptured aneurysms than nonsmokers
  • 50 percent of patients with AAA who do not undergo treatment die of a rupture5

What Are the Symptoms of AAA?

AAA is often called a "silent killer" because there are usually no obvious symptoms of the disease. Three out of four aneurysms show no symptoms at the time they are diagnosed. When symptoms are present, they may include:

  • abdominal pain (that may be constant or come and go)
  • pain in the lower back that may radiate to the buttocks, groin or legs
  • the feeling of a "heartbeat" or pulse in the abdomen

Once the aneurysm bursts, symptoms include:

  • severe back or abdominal pain that begins suddenly
  • paleness
  • dry mouth/skin and excessive thirst
  • nausea and vomiting
  • signs of shock, such as shaking, dizziness, fainting, sweating, rapid heartbeat and sudden weakness

Fortunately, when diagnosed early, AAA can be treated, or even cured, with highly effective and safe treatments.

What Causes an Abdominal Aortic Aneurysm?

Physicians and researchers are not quite sure what causes AAA. The leading thought is that the aneurysm may be caused by inflammation in the aorta, which may cause its wall to break down. Some researchers believe that this inflammation can be associated with atherosclerosis (also called hardening of the arteries) or risk factors that contribute to atherosclerosis, such as high blood pressure (hypertension). In atherosclerosis fatty deposits, called plaque, build up in an artery. Over time, this buildup causes the artery to narrow, stiffen and possibly weaken. Besides atherosclerosis, other factors that can increase your risk of AAA include:

  • Being a man older than 60 years
  • Having an immediate relative, such as a mother or brother, who has had AAA
  • Having high blood pressure
  • Smoking

Your risk of developing AAA increases as you age. AAA is more common in men than in women.

Is this a Serious Condition?

In its early stages, when an AAA is small, it may not pose an immediate health risk. However, your doctor will want to check its condition regularly.

In later stages, if the AAA continues to grow, the aorta’s walls can become thin and lose their ability to stretch. The weakened sections of the aortic wall may become unable to support the force of blood flow. Such an aneurysm could burst, causing serious internal bleeding.

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