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

Jonathan P. Vande Geest, David E. Schmidt, Michael S. Sacks, David A. Vorp

Research output: Contribution to journalArticle

79 Scopus citations

Abstract

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). Rutpured 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.

Original languageEnglish (US)
Pages (from-to)921-932
Number of pages12
JournalAnnals of Biomedical Engineering
Volume36
Issue number6
DOIs
StatePublished - Jun 1 2008

Keywords

  • AAA
  • Aneurysm
  • Anisotropy
  • Biaxial testing
  • Finite element method
  • Stress

ASJC Scopus subject areas

  • Biomedical Engineering

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