Review Question - QID 103654

This patient has an incidental finding of a 4 cm infrarenal abdominal aortic aneurysm (AAA). Surgical repair is indicated if patients are symptomatic, the aneurysm is >5.5cm, or if it grows more than 1cm in a year.

AAA is defined as an enlargement in the diameter of the abdominal aorta of greater than or equal to 3 cm. Risk factors for the development of AAA are male gender, smoking history (at least 100 cigarettes in a lifetime), age >65, hypertension, hypercholesterolemia, peripheral vascular disease, and CAD. The US Preventive Services Task Force recommends that all males age 65-75 years with a smoking history (or those without a smoking history and a first degree relative with AAA) receive a screening abdominal ultrasound to evaluate for the presence of AAA.

Keisler et al. reviews the management of AAA. Treatment of AAA depends on the size of the aneurysm and presence or absence of symptoms. Asymptomatic AAA less than 5.5 cm in diameter are treated by optimizing medical comorbidities and regularly performing surveillance imaging. Asymptomatic AAA's larger than 5.5 cm are electively repaired. AAA's presenting with abdominal, back, groin, or buttock pain are urgently repaired. Ruptured AAA's are emergently repaired.

Sakalihasan et al. review patient factors that are associated with increased rates of aneurysm growth. On average, AAA's enlarge at a rate of .26 cm/y. Factors associated with accelerated growth are smoking (increase of 0.05 cm/y p<.001), elevated diastolic blood pressure (increase of 0.02 cm/y <.001), and size >5cm (increase of 0.4 cm/y, nonsignificant p value). Diabetes has a protective effect, with a reduction of 0.11 cm/y (p = .001) in the rate of aneurysmal growth.

Illustration A is a CT scan depicting an infrarenal abdominal aortic aneurysm with thrombus lining the vessel wall (darker area of the AAA) and central recanalization (lighter area of the AAA).

Incorrect answers:
Answer 2: Smoking history is not an indication for surgical AAA repair. Importantly, however, smoking cessation is the most important intervention in patients who are being treated medically for AAA.
Answer 3: Diameter >5.5 cm (ascending) necessitates surgical repair.
Answer 4: Growth of greater than or equal to 1cm a year is an indication for surgical repair.
Answer 5: Marfan's patients are at increased risk for developing AAA. However, the presence of Marfan's alone is not indication for surgical repair of an AAA.