American Board of Internal Medicine (ABIM) Certification Practice Exam

If the maximum diameter of an abdominal aortic aneurysm is between 3.5 to 4.4 cm, what follow-up is recommended?

1. CT scan

2. Ultrasonography in 6 months

3. Repeat ultrasonography in 1 year

4. Immediate surgery

The correct answer is: Repeat ultrasonography in 1 year

When the maximum diameter of an abdominal aortic aneurysm (AAA) measures between 3.5 to 4.4 cm, the recommended follow-up is to repeat ultrasonography in 1 year. This interval allows for appropriate monitoring of the aneurysm without unnecessary imaging or interventions. The rationale behind this recommendation includes the fact that aneurysms in this size range are considered relatively stable and of lower risk for rupture compared to larger aneurysms. Therefore, an annual follow-up with ultrasonography is sufficient to track any changes in size or morphology of the aneurysm. This process helps to ensure that if the aneurysm grows to a size that approaches the threshold for surgical intervention (typically above 5.5 cm or if rapid expansion is observed), appropriate management can be planned. Other follow-up options, such as a CT scan, are generally more appropriate for larger aneurysms or specific clinical situations where detailed anatomical assessment is necessary. Ultrasonography in 6 months could be seen as unnecessarily frequent for an aneurysm of this size range unless there are specific risk factors or concerns. Immediate surgery is reserved for significantly larger aneurysms or symptomatic cases, not for those in the 3.5 to 4.4 cm range