AAA. Dilation of aorta usually due to atherosclerosis, and >90% originate below the renal arteries. The aneurysms aretypically asymptomatic until they rupture, but patients may complain of lower back or hypogastric pain. The aneurysmsmay be associated with emboli to the feet and kidneys. Normal diameter of the aorta is <2 cm. When the diameter of theAAA is >4.5 cm, repair is generally suggested. Risk of rupture is 1 to 2% over 5 years when the AAA is <5 cm, but 20 to40% when the AAA reaches 6 cm in diameter. The best method of evaluating the AAA is by ultrasound or CT scan.