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

Background and Objective: 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 works aims to compare a range of numerical strategies with varying complexity to evaluate their influence on estimating biomechanical markers relevant for ATAA risk stratification.Methods: Patient-specific models of ATAAs were developed using several numerical strategies, namely: FSI, rigid-wall and moving-wall Computational Fluid Dynamics (CFD), Reduced Order Model (ROM), and Computational Solid Mechanics (CSM). Simulated outputs included blood pressure,Wall Shear Stress (WSS)-based metrics, maximum principal strain, and maximum principal stress. The results of the FSI simulations were used as a reference to assess the relative performance of the alternative strategies.Results: The results showed that all numerical approaches estimated the pressure field with close agreement with FSI. However, WSS estimations differed significantly between the 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 favorable balance between computational cost and numerical accuracy.