American Board of Internal Medicine (ABIM) Certification Practice Exam

What is the maximum diameter of an AAA (Abdominal Aortic Aneurysm) for which repeat ultrasonography is recommended annually?

1. 2.0 to 3.4 cm

2. 3.5 to 4.4 cm

3. 4.5 to 5.4 cm

4. 5.5 to 6.0 cm

The correct answer is: 3.5 to 4.4 cm

For abdominal aortic aneurysms (AAA), annual follow-up with ultrasound is typically recommended for patients with an aneurysm diameter ranging from 3.5 to 4.4 cm. This recommendation is based on the guidelines that assess the risk of rupture versus the benefits of monitoring. In this size range, aneurysms are generally considered to be stable enough to monitor annually without immediate intervention, as the risk of rupture increases significantly once the diameter exceeds 5.5 cm. Regular monitoring allows healthcare providers to check for any significant changes in size or characteristics that may necessitate surgical intervention, ensuring timely management should the aneurysm approach the threshold where surgery is indicated. For smaller aneurysms, such as those between 2.0 and 3.4 cm, follow-up is performed less frequently (typically every three years) because the risk associated with these sizes is substantially lower. On the opposite end, aneurysms larger than 4.4 cm generally lead to more frequent evaluations, and those measuring 5.5 cm or larger typically require consideration of surgical options. Thus, the range of 3.5 to 4.4 cm corresponds to a key threshold for routine, annual monitoring in clinical practice.