Abdominal Aortic Aneurysm Research Today is a free monthly online journal that collates and summarizes the latest research about Abdominal Aortic Aneurysm, including details on aaa (abdominal aortic aneurism), cardiac disease, treatment, symptoms, surgery.

The effects of anisotropy on the stress analyses of patient-specific abdominal aortic aneurysms.

Vande Geest JP, Schmidt DE, Sacks MS, Vorp DA

Department of Aerospace and Mechanical Engineering, University of Arizona, Tucson, AZ 85721, USA.

The local dilation of the infrarenal abdominal aorta, termed an abdominal aortic aneurysm (AAA), is often times asymptomatic and may eventually result in rupture-an event associated with a significant mortality rate. The estimation of in-vivo stresses within AAAs has been proposed as a useful tool to predict the likelihood of rupture. For the current work, a previously-derived anisotropic relation for the AAA wall was implemented into patient-specific finite element simulations of AAA. There were 35 AAAs simulated in the current work which were broken up into three groups: elective repairs (n = 21), non-ruptured repairs (n = 5), and ruptured repairs (n = 9). Peak stresses and strains were compared using the anisotropic and isotropic constitutive relations. There were significant increases in peak stress when using the anisotropic relationship (p < 0.001), even in the absence of the ILT (p = 0.014). Ruptured AAAs resulted in elevated peak stresses as compared to non-ruptured AAAs when using both the isotropic and anisotropic simulations, however these comparisons did not reach significance (p(ani) = 0.55, p(iso) = 0.73). While neither the isotropic or anisotropic simulations were able to significantly discriminate ruptured vs. non-ruptured AAAs, the lower p-value when using the anisotropic model suggests including it into patient-specific AAAs may help better identify AAAs at high risk.

Published 9 May 2008 in Ann Biomed Eng, 36(6): 921-32.
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