A 72-year-old male with a known 6.0 cm abdominal aortic aneurysm undergoes CT angiography for planning endovascular aneurysm repair (EVAR). Which measurement is MOST critical for determining proximal fixation zone adequacy for EVAR?
- A Maximum aneurysm diameter
- B Iliac artery diameter
- C Infrarenal neck length and angulation ✓
- D Distance from renal arteries to aortic bifurcation
Correct answer: C. Infrarenal neck length and angulation
Explanation
Adequate proximal fixation zone (infrarenal neck) is the most critical anatomical criterion for EVAR suitability. Standard EVAR requires an infrarenal neck length ≥15 mm, diameter ≤32 mm, and angulation <60° for proximal seal. Short, angulated, or heavily calcified necks increase risk of type I endoleak. Maximum aneurysm diameter determines the threshold for intervention (5.5 cm in males). Iliac access is assessed for delivery sheath compatibility. Renal-to-bifurcation distance affects limb positioning but is secondary.
Reference: Grainger & Allison's Diagnostic Radiology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.