Abdominal Aortic Aneurysm Screening

• The majority of people who have an aneurysm have no symptoms.
  
  
• This highly hereditary condition is usually fatal if an aneurysm rupture occurs.
  
  
• There are approximately 16,000 deaths each year in the United States from ruptured Abdominal Aortic Aneurysm.

An aneurysm is a localized area of widening of a blood vessel. The aorta in this instance bulges at the site of an aneurysm like a weak spot on a worn inner tube of a tire.   90% of aneurysms occur in the abdominal aorta in the abdomen.   The most common cause of aneurysm is atherosclerosis. There is also a strong hereditary component for AAA and there is a 15 - 19% incidence among first degree relatives. Five percent of men over the age of 60 will develop an abdominal aortic aneurysm.    Most AAAs cause no symptoms until rupture.

If there are any symptoms, it is usually a deep boring pain in the back.    Most aneurysms (80%) demonstrate progressive enlargement. The diameter of an aneurysm is directly related to its risk of rupture. For aneurysms smaller than 4 centimeters in diameter, the risk of rupture is less than 10%. Once an aneurysm is 4 to 5 cm in diameter, the risk of rupture increases to almost 25%. Rupture of an AAA is a catastrophic  event with an associated mortality rate as high as 75%. With surgery to repair the abdominal aortic aneurysm, the surgical mortality rate is less than 5%. Approximately  40,000 patients undergo aneurysm repair each year. In the United States, 16,000 deaths are attributed to AAA each year.

Because of its portability, lack of ionizing radiation, cost and availability, Ultrasound should be the initial modality for screening for AAA and it is the test of choice for follow up of abdominal aortic aneurysm. Ultrasound has a sensitivity of 95% and a specificity of nearly 100% when performed in a setting with adequate quality assurance. Abdominal palpation has poor accuracy and is not an adequate screening test.