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What is Abdominal Aortic Aneurysms?
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 abdominal aortic 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.
How common are Abdominal Aortic Aneurysms?
About 4 in 100 men and about 1 in 100 women over the age of 65 have an AAA. It becomes more common with increasing age. However, most people with an AAA are not aware that they have one (see below in the section on symptoms). An AAA is rare in people under the age of 60.
What are some predisposing factors for Abdominal Aortic Aneurysms?
- Smoking
- Heredity
- Congenital defects, such as an inherited weakness in the blood vessel wall; example, Marfan’s syndrome
- Injury
- Infection
- High blood pressure (hypertension). This speeds up damage to blood vessel walls.
- Arteriosclerosis (also called atherosclerosis). This occurs when the normal lining of the arteries deteriorates, the walls of the arteries thicken, and deposits of fat and plaque block the flow of blood through the arteries. The association of arteriosclerosis with the development of aneurysms is controversial.
- High cholesterol
What are the Types of Abdominal Aortic Aneurysms?
Abdominal aortic aneurysms are usually classified by their size and the speed at which they are growing. These two factors can help to predict the likely health effects of the aneurysm
Small or Slow Growing Abdominal Aortic Aneurysms generally have a lower risk of rupture than larger or fast-growing aneurysms. Often, a doctor will decide that it’s safer to monitor an aneurysm with regular abdominal ultrasounds than it is to treat it.
Large or Fast Growing Abdominal Aortic Aneurysms are more likely to rupture than small aneurysms. This can lead to internal bleeding and other serious complications. The larger the aneurysm is, the more likely it will need to be treated with surgery. Aneurysms also need to be treated if they are causing symptoms or leaking blood.
What is the chance of an Abdominal Aortic Aneurysms rupturing?
The chance of rupture is low if an AAA is small. As a rule, the risk of rupture increases with increasing size. This is much like a balloon – the larger you blow it up, the greater the pressure, and the greater the chance it will burst. The diameter of an AAA can be measured by an ultrasound scan. The following gives overall risk figures for the size (diameter) of the aneurysm:
- 40 mm-55 mm: about a 1 in 100 chance of rupture per year.
- 55 mm-60 mm: about a 10 in 100 chance of rupture per year.
- 60 mm-69 mm: about a 15 in 100 chance of rupture per year.
- 70 mm-79 mm: about a 35 in 100 chance of rupture per year.
- 80 mm or more: about a 50 in 100 chance of rupture per year.
As a rule, for any given size, the risk of rupture is increased in smokers, females, those with high blood pressure, and those with a family history of an AAA.
Treating an Abdominal Aortic Aneurysm
Depending on the size and exact location of the aneurysm, your doctor may perform surgery to repair or remove the damaged tissue. This may be done either with open abdominal surgery or endovascular surgery. The surgery performed will depend on your overall health and the type of aneurysm.
Open-Abdominal Surgery is used to remove damaged areas of the aorta. It is an invasive form of surgery and has a longer recovery time. Open-abdominal surgery may be necessary if your aneurysm is very large or has already ruptured.
Endovascular Surgery is a less invasive form of surgery. It uses a graft to repair the weakened walls of the aorta.
For a small abdominal aortic aneurysm (less than 1.6 inches in size), your doctor may decide to monitor the aneurysm regularly instead of performing surgery. Surgery has risks, and small aneurysms generally do not rupture.
