Insurance issues aside, most vascular surgeons wait until the aneurysm
is 5cm or larger before operating. The exception is if the aneurysm started growing rapidly.
Why? Actually, it's simple. Numerous studies have shown that there is no mortality benefit to fixing a 'small' aneurysm. The risk from the surgery for a small AAA is actually higher than the risk from the aneurysm.
If the AAA is around 4cm, then we usually get annual ultrasounds.