75 - Abdominal aortic aneurysm repair

Summary

In the USA, where aortic aneurysm rupture is the tenth leading cause of death in men older than 55 years, recent evidence suggests that the death rate from abdominal aortic aneurysms has increased in the past several decades. Potential explanations for the apparent rise include an aging population, improved radiologic detection, and closer observation of families and first-degree relatives of patients with abdominal aortic aneurysms. The mortality in patients with ruptured aneurysms ranges from 78% to 94%, with half of those patients dying before they reach the hospital. Elective or non-emergent aneurysm repair carries a mortality rate 10 to 25 times lower than that in patients with ruptured aneurysms; hence, emphasis should be on detection, evaluation, and planned surgery, the key concept being that aneurysms are relatively easily and safely treated in the elective setting. Unfortunately, 12% of patients initially present with rupture.

After an aneurysm of the abdominal aorta is detected, whether by physical examination, plain radiography of the abdomen, computed tomography, magnetic resonance imaging, or B-mode ultrasonography, the urgency and timing of repair must be determined. According to Laplace's law, the likelihood of aneurysm rupture is proportional to maximal aneurysm diameter. The yearly risk of rupture is 1% to 4% for small aneurysms (less than 5 cm in diameter), 6% to 11% for aneurysms 5 to 7 cm, and over 20% for aneurysms greater than 7 cm.