What is
the natural history of untreated abdominal aortic aneurysm (AAA)?
The natural history of all aneurysms is to
expand in size. The tendency to rupture is primarily dependent on wall stress,
which increases as the aneurysm enlarges, according to Laplace’s law:
Tension = Pressure × Radius/2 ×Wall Thickness
The average growth rate of aortic aneurysms is
0.4 cm per year. A follow-up study of high-risk patients reported an overall
rupture rate of 3% and a surgical mortality (elective surgery for aneurysm size
>6 cm or with symp-toms) of 4.9%. Thirty-four percent of mortalities were
due to causes unrelated to the aneurysm. The 5-year survival for untreated AAA
>6 cm was less than 10%, while the 5-year survival for untreated AAA <6
cm was 50%. Elevated diastolic blood pressure, aneurysm anteroposte-rior
diameter >5 cm, and obstructive pulmonary disease were independent predictors
of rupture. Predicted 5-year rupture rates varied from 2% when these risk
factors were absent to 100% when all three risk factors were present.
Related Topics
Privacy Policy, Terms and Conditions, DMCA Policy and Compliant
Copyright © 2018-2023 BrainKart.com; All Rights Reserved. Developed by Therithal info, Chennai.