What size of an abdominal aortic aneurysm (AAA) usually warrants repair?

• A. 3 cm
• B. 4 cm
• C. 5 cm
• D. 6 cm

Answer: (C)

An abdominal aortic aneurysm (AAA) typically warrants repair when it reaches a size of 5 cm or more. This threshold is based on clinical studies showing that the risk of rupture significantly increases once the aneurysm exceeds this size. Aneurysms measuring 5 cm or larger have a higher incidence of catastrophic events, and thus the risk-benefit ratio favors surgical intervention at this point.

In practice, smaller aneurysms, such as those measuring 3 cm and 4 cm, are often monitored with regular imaging to assess for growth rather than being subjected to repair unless certain risk factors or symptoms are present. By waiting until the aneurysm reaches 5 cm or more, medical professionals can mitigate unnecessary surgical risks associated with repairing smaller, asymptomatic aneurysms.

The 6 cm threshold is indeed a significant size for repair, but it is generally a guideline for very large aneurysms where the risk of rupture is even greater, thus reinforcing the decision to intervene before reaching that size. Therefore, the standard recommendation to repair an AAA is at 5 cm, making that the correct answer for the criteria used in determining when to proceed with surgical intervention.