Fluid-Structure Interaction in Abdominal Aortic Aneurysm: Effect of Modeling Techniques.

Area of Science:

• Biomedical Engineering
• Computational Mechanics
• Cardiovascular Research

Background:

• Abdominal aortic aneurysm (AAA) rupture is a life-threatening condition.
• Accurate prediction of AAA mechanical behavior is essential for clinical decision-making.
• Current modeling techniques vary in their ability to capture complex AAA hemodynamics and mechanics.

Purpose of the Study:

• To systematically investigate the impact of different modeling techniques on predicting AAA mechanical behaviors.
• To compare the accuracy of fluid-structure interaction (FSI) models with simplified computational fluid dynamics (CFD) and computational solid stress (CSS) models.
• To provide guidance on selecting appropriate modeling techniques for AAA analysis.

Main Methods:

• Development and application of a fluid-structure interaction (FSI) model.
• Comparison of FSI model results with standalone computational fluid dynamics (CFD) and computational solid stress (CSS) models.
• Analysis of blood flow dynamics, wall stresses, and deformation within the AAA sac.

Main Results:

• CFD models showed smaller vortices and overestimated fluid wall shear stress compared to FSI.
• FSI and CSS models exhibited minimal differences in wall stresses and deformation.
• CSS model accuracy was dependent on the applied pressure profile; large pressure drops led to underestimation of wall stresses.
• Isotropic AAA wall properties exacerbated discrepancies between simplified models and FSI.

Conclusions:

• Modeling technique significantly impacts the prediction of AAA blood flow dynamics and wall mechanics.
• FSI models provide a more comprehensive understanding of AAA behavior.
• Careful consideration of modeling assumptions, such as wall properties and pressure profiles, is necessary for accurate AAA risk assessment.
• This study guides the selection of appropriate modeling techniques for clinical applications.