Fluid-Structure Interaction Simulations of Repaired Type A Aortic Dissection: a Comprehensive Comparison With Rigid...

Area of Science:

• Biomedical Engineering
• Computational Fluid Dynamics
• Cardiovascular Research

Background:

• Surgically repaired type A aortic dissection (TAAD) presents complex intraluminal hemodynamics.
• Accurate hemodynamic prediction is crucial for understanding disease progression and treatment outcomes.

Purpose of the Study:

• To evaluate the influence of aortic wall compliance on hemodynamics in post-surgery TAAD.
• To compare fluid-structure interaction (FSI) simulations with rigid wall models for TAAD.

Main Methods:

• Patient-specific TAAD models were created using computed tomography angiography.
• Fully coupled two-way FSI simulations were performed, incorporating prestress and varied material properties.
• Hemodynamic parameters (velocity, wall shear stress, pressure difference) were compared between FSI and rigid wall models.

Main Results:

• FSI simulations predicted significantly lower blood velocities and wall shear stress (WSS) compared to rigid models.
• Low time-averaged WSS regions were substantially larger in FSI models (e.g., 38 cm² vs. 21 cm² in patient 1).
• Wall compliance had a minimal effect on the pressure difference between true and false lumens (<0.25 mmHg).

Conclusions:

• FSI simulations are essential for accurately predicting low WSS regions in surgically repaired TAAD.
• Rigid wall computational fluid dynamics (CFD) is adequate for predicting intraluminal pressure differences in these cases.
• Aortic wall compliance plays a critical role in modulating hemodynamic forces within repaired TAAD.