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 journalArticlepeer-review

80 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 2008

Keywords

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

ASJC Scopus subject areas

  • Biomedical Engineering

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