A 65-year-old man with a history of smoking has a 6 cm infrarenal aortic aneurysm found incidentally on CT. The risk of rupture correlates most with which parameter?

• A Calcification extent in the aneurysm wall
• B Presence of mural thrombus within the aneurysm sac
• C Duration of aneurysm since first detection on imaging
• D Maximum aneurysm diameter — rupture risk increases sharply when diameter exceeds 5.5 cm ✓

Explanation

The annual rupture risk of AAA is directly related to maximum transverse diameter: <4 cm (~0%), 4–5 cm (~1%), 5–6 cm (~5–10%), >6 cm (~10–20% per year). Surgical repair (open or EVAR) is recommended when diameter reaches 5.5 cm in men or 5.0 cm in women, or if rapid expansion occurs (>0.5 cm in 6 months). Mural thrombus does not predictably reduce rupture risk.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.