Abdominal Aortic Aneurysms

The term aneurysm is derived from the Greek word (aneurysmos) meaning dilatation. The most common site for true arterial aneurysms is the infra-renal aorta. A true aneurysm is a circumscribed dilatation of the three layers of vessel wall with a diameter increase of at least 50% compared to that of the proximal segment (i.e., the the dilated segment is 1.5 times that of the adjacent proximal segment). Ectasia, on the other hand, is a mild dilatation (luminal diameter increased by <50%) that is due to age-related degenerative changes in the vessel wall. Pheotypically, aneurysms are further classified as fusiform (symmetric involvement of the entire aortic circumference) or saccular (focal outpouching of part of the vessel wall). While most aneurysms are silent, a variety of symptoms and life-threatening complications can occur. Timely diagnosis and treatment of aortic aneurysms is critical.