Annals of Biomedical Engineering

, Volume 38, Issue 4, pp 1288–1313 | Cite as

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


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.


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



Abdominal aortic aneurysm


Diastolic blood pressure






Magnetic resonance imaging


Mean wall shear stress


Oscillatory shear index




Systolic blood pressure




Turbulent kinetic energy



The authors would like to thank Victoria Yeh and Allen Chiou for their assistance in constructing the computer models, Mary McElrath and Julie White for their assistance with patient recruitment, and Sandra Rodriguez, Romi Samra, Anne Sawyer, Dr. Janice Yeung, Dr. Geoffrey Schultz, and Dr. Byard Edwards and all staff at the Lucas Center at Stanford University for assistance with imaging. This study was supported by the National Institutes of Health (Grants P50 HL083800, 2RO1 HL064338, P41 RR09784, and U54 GM072970) and the National Science Foundation (0205741, and CNS-0619926 for computer resources).


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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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