The aorta is the major artery that supplies oxygenated blood throughout the body. The section of the aorta that traverses the abdominal area is called the abdominal aorta. The abdominal aorta is normally about 2 cm in diameter, and if the abdominal aorta is dilated to greater than 3 cm, it is termed an abdominal aortic aneurysm (AAA).
Smoking is a major risk factor for an AAA. Abdominal aortic aneurysms in smokers tend to grow faster and have an increased risk of rupture, a feared complication associated with a very high mortality rate of over 80%.
Some other risk factors for AAA include age over 60, family history of AAA, male gender, hypertension, elevated lipids, atherosclerosis and obesity. Chronic inflammation is felt to be a contributing process to the pathogenesis of an AAA, which is a property shared in common with coronary artery disease and valvular heart disease.
While AAAs are less common in women, an AAA in a female is more likely to rupture than one in a male. Surprisingly, diabetes may be associated with a decreased risk of developing an AAA, although the reason is unclear.
IMPORTANT ISSUES in the assessment of applicants with AAAs include the size and stability of the aneurysm, adequacy of follow up, including imaging, and whether symptoms are present. Adequacy of cardiovascular risk factor control is also important. It would be concerning, for instance, if the blood pressure is uncontrolled.
AAAs may be asymptomatic, although symptoms such as abdominal pain, which may radiate to the back, can occur. The presence of symptoms points to an increased risk of rupture. Sometimes a palpable pulsating mass may be identified on abdominal examination.
AAAs tend to become larger over time, with an average annual growth rate of about 2 mm to 3 mm, although the expansion rate can vary in any given individual. The risk of rupture of an aneurysm is related to its diameter and is significantly increased once the diameter reaches 5.5 cm or larger.
The imaging modality most commonly used to screen for an AAA is an ultrasound. The U.S. Preventive Services Task Force, a panel of experts who make primary care recommendations, advocates a one time screening for AAAs by ultrasonography in men aged 65 to 75 years of age who have ever smoked and selective screening for nonsmokers in that group.
It is generally recommended to perform follow up surveillance ultrasounds for asymptomatic AAAs under 5.5 cm in diameter and to refer for surgical repair symptomatic AAAs or those at least 5.5 cm in diameter, although women may benefit from surgery at a smaller diameter. Surgery might also be recommended for AAAs with a rapid rate of expansion. The recommended monitoring interval depends upon the size of the AAA, and varies from six months to three years, with larger aneurysms requiring more frequent imaging.
While open surgical repair had been the treatment of choice to electively repair AAAs, less invasive endovascular repair is now more commonly performed. Endovascular repair utilizes a graft that is placed through a catheter to strengthen the aorta and prevent the aneurysm from rupturing.
APPLICANT 1 is a 65 year old who was sent for a screening abdominal sonogram one month ago that revealed a 3.5 cm AAA, with no prior studies available. Since this is a newly discovered AAA with no track record of stability the case would be postponed.
APPLICANT 2 is an asymptomatic 65 year old with a 3.9 cm AAA that has been well followed and stable for four years. The most recent sonogram was two months ago. This can be Four Tables.
APPLICANT 3 is a 68 year old who had resection of a 6 cm AAA four years ago. He is well followed and doing well. This can be Four Tables.