Abdominal aortic aneurysms.

Abdominal aortic aneurysms are usually atherosclerotic in origin and infrarenal in location. They most commonly occur in patients over 50 and often are entirely asymptomatic. Although not essential for diagnosis, arteriography is necessary for proper planning of the operative procedure. Ultrasound and computerized axial tomography provide equal or superior diagnostic accuracy. The mortality rate from rupture of even small aneurysms is greater than the elective operative mortality. In the absence of absolute contraindications, aneurysms larger than 4.5 cm. should be surgically treated.