A comparison of modelling techniques for computing wall stress in abdominal aortic aneurysms

Area of Science:

• Biomedical Engineering
• Computational Mechanics
• Cardiovascular Research

Background:

• Abdominal aortic aneurysms (AAA) are a major cause of cardiovascular death.
• Current clinical decisions for AAA intervention rely on maximum diameter, a potentially inadequate measure.
• Patient-specific finite element analysis (FEA) offers a more nuanced approach to predicting AAA rupture risk.

Purpose of the Study:

• To compare different computational modeling approaches for assessing wall stress in patient-specific abdominal aortic aneurysms (AAA).
• To evaluate the impact of model complexity and material properties on AAA wall stress calculations.
• To determine the clinical relevance of advanced FEA techniques for AAA rupture prediction.

Main Methods:

• A patient-specific AAA was 3D reconstructed and modeled using three distinct approaches: AAA(SIMP), AAA(MOD), and AAA(COMP).
• Both linear and non-linear material properties were applied to each model.
• Wall stress distributions were analyzed using the finite element method.

Main Results:

• Significant differences in peak wall stress were observed across the three modeling methods.
• Utilizing more realistic parameters, including non-linear material properties and intraluminal thrombus, reduced calculated peak wall stress.
• The most accurate non-linear complex approach showed a 59% reduction in wall stress compared to a model without intraluminal thrombus.

Conclusions:

• The accuracy of computational modeling for AAA wall stress is highly dependent on the realism of input parameters.
• Simplified modeling techniques can lead to inaccurate stress distributions and potentially flawed clinical interpretations.
• Careful consideration of modeling methodologies is essential for ensuring the clinical significance of FEA in AAA management.