Comparison of Numerical Models to Compute Biomechanical Markers in Ascending Thoracic Aortic Aneurysms

Numerical modelling of Ascending Thoracic Aortic Aneurysms (ATAAs) biomechanics has the potential for enhancing current clinical guidelines. Fluid-Structure Interaction (FSI) is considered the gold-standard approach to perform such analyses. However, this approach significantly increases simulation time, potentially limiting its applicability in clinical workflows. This work compares a range of numerical strategies of varying complexity to evaluate their influence on estimating biomechanical markers relevant for ATAA risk stratification. Patient-specific models of ATAAs were developed using FSI, rigid-wall and movingwall Computational Fluid Dynamics (CFD), Reduced Order Model (ROM), and Computational Solid Mechanics (CSM). Simulated outputs included blood pressure, Wall Shear Stress (WSS)-based metrics, and maximum principal stress and strain. The FSI results served as the reference to assess the alternative strategies. All approaches estimated the pressure field in close agreement with FSI, whereas WSS estimations differed significantly between models. Coupling CSM and ROM or moving wall CFD produced a close agreement with FSI regarding the maximum principal strain and stress. Conclusions: Depending on the application and required level of detail, simplified strategies such as ROM or moving-wall CFD coupled with CSM may offer a favourable balance between computational cost and numerical accuracy.