Most Common Location of Abdominal Aortic Aneurysm
The infrarenal abdominal aorta—the segment between the renal arteries and the aortic bifurcation—is the most common location for abdominal aortic aneurysms, accounting for approximately 85% of all AAAs. 1
Anatomic Distribution
The infrarenal location dominates AAA pathology for several key reasons:
- Approximately 85% of all abdominal aortic aneurysms occur in the infrarenal segment, making this the overwhelmingly predominant site 1, 2
- The infrarenal aorta extends from below the lowest renal artery down to the aortic bifurcation into the common iliac arteries 1
- Only about 5% of AAAs involve the visceral branches (suprarenal segment), making suprarenal involvement relatively uncommon 3
- The infrarenal-only pattern represents roughly 85% of atherosclerotic abdominal aortic aneurysms 1
Clinical Implications of Infrarenal Location
Understanding this anatomic predilection has direct management consequences:
- Proximal neck anatomy—the segment between the lowest renal artery and the aneurysm's beginning—becomes the critical landing zone for endovascular repair planning 1
- Conventional EVAR requires a proximal neck length greater than 10-15 mm and diameter less than 30 mm to achieve adequate seal 1
- The distal landing zone typically includes one or both common iliac arteries 1
Important Caveats
Despite the 85% infrarenal predominance, comprehensive imaging of the entire aorta from thoracic to iliac segments remains essential to avoid missing concurrent thoracic aneurysms or suprarenal extension 1. This is particularly important because:
- Approximately 50% of patients present with aneurysm morphology unsuitable for conventional EVAR, requiring fenestrated/branched techniques or open repair 1
- Mycotic (infected) AAAs preferentially occur in the suprarenal aorta rather than the typical infrarenal location, representing an important exception to the general rule 1
The infrarenal location's dominance reflects the degenerative atherosclerotic process that drives most AAA formation 2, with the infrarenal segment being particularly vulnerable to the mechanical stress and structural changes that lead to aneurysmal dilatation 4.