The most common aneurysm in general vascular practice is the abdominal aortic aneurysm (AAA). The normal maximum aortic diameter is about 2 cm, so 3 cm is taken to be the minimum size for it to be aneurysmal; 2–3 cm is ectatic.
Key Facts:
Approximately 8% of men over the age of 65 have an AAA.
Men are affected 6 times more often than women.
Caucasians are affected more than Asians or Africans.
Five per cent of people with an AAA also have a popliteal aneurysm.
The vast majority of AAAs are infrarenal (i.e. below the renal arteries). Fewer than 10% involve the suprarenal aorta and these are much more difficult to treat. Juxtarenal AAAs are technically infrarenal; however, they are aneurysmal right up to the renal arteries with no normal diameter neck.
AAAs may extend into the iliac arteries.
Five to ten per cent of AAAs have an inflammatory wall and are called ‘inflammatory aneurysms’, characterised by marked thickening of the aneurysmal wall and often retroperitoneal fibrosis.
