An abdominal aortic aneurysm (AAA, or “triple A”) is an abnormal dilation of the abdominal aorta, usually due to atherosclerosis. An aneurysm is considered to be present when the diameter exceeds 3 cm and the most common site is the infrarenal aorta.
Risk factors include smoking, hypertension, male gender, race (more common in whites), and advanced age. Most AAAs are asymptomatic and are discovered as incidental findings on physical exam, ultrasound, or CT. As AAAs expand symptoms may range from vague epigastric pain to back and abdominal pain, but most aneurysms grow slowly without symptoms. AAAs grow approximately 2-3 mm/year on average. However, some AAAs may expand exponentially while others remain the same size indefinitely.
Surgical repair is indicated for for AAA > 5.5 cm in diameter or any size AAA with rapid growth. AAA rupture is a surgical emergency with a high mortality rate. The classic triad of a AAA rupture is excruciating abdominal pain that radiates to the back, a pulsatile abdominal mass, and hypotension.