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On the abdominal aortic aneurysms: pulsatile state considerations
N Viswanath1, C M Rodkiewicz, S Zajac
1Department of Mechanical Engineering University of Alberta, Edmonton, Canada.
Medical Engineering & Physics
|June 1, 1997
Summary
This study numerically investigated pulsatile blood flow in abdominal aortic aneurysms. Findings show the distal aneurysm end experiences maximum stress, suggesting blood flow mechanics are crucial for aneurysm development and growth.
Area of Science:
- Fluid Dynamics
- Biomedical Engineering
- Computational Mechanics
Background:
- Abdominal aortic aneurysms (AAAs) pose significant health risks.
- Understanding blood flow dynamics within AAAs is crucial for predicting disease progression.
- Pulsatile flow characteristics and their impact on AAA wall stress are not fully elucidated.
Purpose of the Study:
- To numerically investigate pulsatile blood flow in rigid-walled abdominal aortic aneurysm models.
- To analyze the formation of vortices and stagnation zones under realistic pressure-velocity conditions.
- To determine the role of mechanical forces from pulsatile blood flow in AAA development and growth.
Main Methods:
- Utilized transient Navier-Stokes equations for axisymmetric geometry.
- Applied actual abdominal aorta pressure-velocity pulse as inlet boundary conditions.
- Assumed a fully developed parabolic velocity profile at the inlet for each time-step.
Main Results:
- Identified maximum shear stress and pressure at the distal end of the aneurysm throughout the cardiac cycle.
- Observed time-dependent vortex formation and stagnation zones within the aneurysm sac.
- Demonstrated that pulsatile flow-induced mechanical forces significantly influence AAA development and expansion.
Conclusions:
- Pulsatile blood flow mechanics are critical in the pathogenesis of abdominal aortic aneurysms.
- A quasi-steady state analysis can sufficiently explain basic flow characteristics within the aneurysm.
- Wall shear stress at the distal end under adverse conditions is comparable between pulsatile and quasi-steady states.
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