An abdominal aortic aneurysm (AAA, so called triple-A) is a localized bulging, result of an aortic wall weakness. The aorta is the main blood vessel (~2cm diameter) that carries blood from the heart to the rest of the body.

It runs through the chest (thoracic aorta) down to the abdomen (abdominal aorta) and eventually splits to the right and left iliac arteries to supply the legs. An abdominal aortic aneurysm can develop anywhere along the abdominal aorta but the majority of cases develop below the renal arteries (infrarenal aneurysms) which connect the aorta to the kidneys. They can vary in size and as they grow larger there is an increasing risk for rupture.

abdominal aortic aneurysm

Since a ruptured aneurysm is extremely dangerous and can cause life-threatening bleeding, aneurysms are best corrected by an operation before this happens.

Multiple factors have been related to the development of an abdominal aortic aneurysm and there is definitely a hereditary component. Atherosclerosis (hardening of the arteries) is an important risk factor for the development of an aortic aneurysm, as it leads to a diseased weak aortic wall.

This is usually the result of smoking, high blood pressure (hypertension), high cholesterol (hypercholesterolemia) and/or aging (>60 years old). Aortic aneurysms are more frequent in men and can develop even in the absence of atherosclerosis:

Heredity (immediate relatives with an aortic aneurysm)
Congenital defects, such as an inherited weakness in the blood vessel wall (connective tissue disorders): Marfan's syndrome, Ehlers-Danlos syndrome, Turner's syndrome and polycystic kidney disease
Other congenital disorders: bicuspid aortic valve, coarctation of the aorta
Infection (aortitis)