Annals of Biomedical Engineering

, Volume 38, Issue 4, pp 1288–1313

Quantification of Hemodynamics in Abdominal Aortic Aneurysms During Rest and Exercise Using Magnetic Resonance Imaging and Computational Fluid Dynamics

  • Andrea S. Les
  • Shawn C. Shadden
  • C. Alberto Figueroa
  • Jinha M. Park
  • Maureen M. Tedesco
  • Robert J. Herfkens
  • Ronald L. Dalman
  • Charles A. Taylor
Article

DOI: 10.1007/s10439-010-9949-x

Cite this article as:
Les, A.S., Shadden, S.C., Figueroa, C.A. et al. Ann Biomed Eng (2010) 38: 1288. doi:10.1007/s10439-010-9949-x

Abstract

Abdominal aortic aneurysms (AAAs) affect 5–7% of older Americans. We hypothesize that exercise may slow AAA growth by decreasing inflammatory burden, peripheral resistance, and adverse hemodynamic conditions such as low, oscillatory shear stress. In this study, we use magnetic resonance imaging and computational fluid dynamics to describe hemodynamics in eight AAAs during rest and exercise using patient-specific geometric models, flow waveforms, and pressures as well as appropriately resolved finite-element meshes. We report mean wall shear stress (MWSS) and oscillatory shear index (OSI) at four aortic locations (supraceliac, infrarenal, mid-aneurysm, and suprabifurcation) and turbulent kinetic energy over the entire computational domain on meshes containing more than an order of magnitude more elements than previously reported results (mean: 9.0-million elements; SD: 2.3 M; range: 5.7–12.0 M). MWSS was lowest in the aneurysm during rest 2.5 dyn/cm2 (SD: 2.1; range: 0.9–6.5), and MWSS increased and OSI decreased at all four locations during exercise. Mild turbulence existed at rest, while moderate aneurysmal turbulence was present during exercise. During both rest and exercise, aortic turbulence was virtually zero superior to the AAA for seven out of eight patients. We postulate that the increased MWSS, decreased OSI, and moderate turbulence present during exercise may attenuate AAA growth.

Keywords

Turbulence Mean wall shear stress Oscillatory shear index Mesh independence Flow waveforms Blood pressure Windkessel boundary condition Patient-specific 

Abbreviations

AAA

Abdominal aortic aneurysm

DBP

Diastolic blood pressure

IR

Infrarenal

Mid-An

Mid-aneurysm

MRI

Magnetic resonance imaging

MWSS

Mean wall shear stress

OSI

Oscillatory shear index

SB

Suprabifurcation

SBP

Systolic blood pressure

SC

Supraceliac

TKE

Turbulent kinetic energy

Copyright information

© Biomedical Engineering Society 2010

Authors and Affiliations

  • Andrea S. Les
    • 1
  • Shawn C. Shadden
    • 2
  • C. Alberto Figueroa
    • 1
  • Jinha M. Park
    • 3
  • Maureen M. Tedesco
    • 4
  • Robert J. Herfkens
    • 5
  • Ronald L. Dalman
    • 4
  • Charles A. Taylor
    • 1
    • 6
  1. 1.Department of BioengineeringStanford UniversityStanfordUSA
  2. 2.Department of Mechanical and Aerospace EngineeringIllinois Institute of TechnologyChicagoUSA
  3. 3.Department of RadiologyUniversity of Southern CaliforniaLos AngelesUSA
  4. 4.Division of Vascular SurgeryStanford UniversityStanfordUSA
  5. 5.Department of RadiologyStanford UniversityStanfordUSA
  6. 6.James H. Clark CenterStanfordUSA

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