Fluid structure interaction of patient specific abdominal aortic aneurysms: a comparison with solid stress models

Area of Science:

• Biomedical Engineering
• Computational Fluid Dynamics
• Medical Imaging

Background:

• Abdominal aortic aneurysm (AAA) is a life-threatening aortic dilation.
• Maximum diameter is an unreliable indicator of AAA rupture risk.
• Wall stress analysis offers a promising alternative for predicting AAA rupture.

Purpose of the Study:

• To compare static and dynamic wall stress analyses in patient-specific AAA models.
• To evaluate the influence of pulsatile flow on AAA wall stress.
• To determine the necessity of complex fluid-structure interaction (FSI) models for AAA rupture prediction.

Main Methods:

• Patient-specific AAA models were constructed from CT scans.
• Fluid-structure interaction (FSI) and static structural (SS) simulations were performed.
• AAA walls were modeled as non-linear hyperelastic material using commercial finite element code.

Main Results:

• Wall stress patterns, wall shear stress, pressure, and velocity fields were analyzed.
• Inclusion of fluid flow slightly altered local wall stresses.
• Peak wall stress differences between SS and FSI models were negligible (<1%).

Conclusions:

• Fully coupled FSI simulations offer minimal added value for AAA rupture risk prediction.
• Static structural (SS) models are sufficient and computationally efficient for AAA rupture risk assessment.
• The findings support the continued use of SS models in clinical practice.