American Board of Internal Medicine (ABIM) Certification Practice Exam

In AAA surveillance, how frequently should ultrasonography be performed for an AAA measuring 3.5 to 4.4 cm?

1. Every month

2. Annually

3. Every 2 years

4. Every 3 years

The correct answer is: Annually

For patients with an abdominal aortic aneurysm (AAA) measuring between 3.5 to 4.4 cm, the recommended frequency for ultrasonography surveillance is annually. This recommendation stems from guidelines established to monitor the growth of the aneurysm and assess the risk of rupture. The rationale for this annual monitoring is based on the growth rate of AAAs in this size range, which typically averages about 1 to 2 mm per year. Regular assessments allow for timely intervention should the aneurysm grow to a size where the risk of rupture increases significantly, traditionally at sizes greater than 5.5 cm. By performing ultrasonography annually, clinicians can effectively track any changes in the aneurysm size and adjust management strategies accordingly. Surveillance at different intervals, such as monthly or every few years, would not align with established guidelines as they either increase the burden of unnecessary imaging without significant clinical benefit or fail to provide adequate monitoring to catch rapid changes in the aneurysm's size. Therefore, the most prudent and standard approach for AAAs within the mentioned size range is annual ultrasonography.