A decoupled fluid structure approach for estimating wall stress in abdominal aortic aneurysms

Area of Science:

• Biomedical Engineering
• Cardiovascular Research
• Medical Imaging

Background:

• Abdominal aortic aneurysm (AAA) rupture risk assessment is clinically significant.
• Current methods like static structural analysis neglect flow-induced stress variations.
• Accurate patient-specific wall stress and tissue properties are crucial for risk prediction.

Purpose of the Study:

• To evaluate the effectiveness of a decoupled fluid-structure analysis for AAA wall stress.
• To compare this approach against traditional static analysis for AAA rupture risk.
• To assess the clinical utility of detailed AAA wall stress distribution.

Main Methods:

• Patient-specific AAA models created from CT image 3D reconstruction.
• Inflow/outflow boundary conditions derived from patient data for flow simulations.
• Static structural analysis with uniform and non-uniform (flow-induced) pressure loading.
• Hyperelastic arterial wall and elastic intraluminal thrombus models used.

Main Results:

• Static analysis captures general stress features but underestimates peak wall stress by up to 12.5%.
• The decoupled fluid-structure approach yields higher peak wall stress values.
• The decoupled method offers insights into aneurysmal sac hemodynamics.

Conclusions:

• Decoupled fluid-structure analysis offers a more accurate assessment of AAA wall stress compared to static methods.
• This improved stress quantification can enhance AAA rupture risk prediction.
• The approach provides valuable hemodynamic information within the aneurysm sac.