Comparative analysis of Zero Pressure Geometry and prestress methods in cardiovascular Fluid-Structure Interaction

• Published in: Computer methods and programs in biomedicine 2024-12, Vol.257, p.108475, Article 108475
• Main Authors: Mourato, André, Valente, Rodrigo, Xavier, José, Brito, Moisés, Avril, Stéphane, Tomás, António C., Fragata, José
• Format: Article
• Language: English
• Subjects: Ascending Thoracic Aortic Aneurysms (ATAA); Biomechanics; Fluid-Structure Interaction (FSI); Mechanics; Physics; Prestress Tensor (PT); Zero Pressure Geometry (ZPG)
• ISSN: 0169-2607; 1872-7565; 1872-7565
• DOI: 10.1016/j.cmpb.2024.108475

Modelling patient-specific aortic biomechanics with advanced computational techniques, such as Fluid–Structure Interaction (FSI), can be crucial to provide effective decision-making indices to enhance current clinical practices. To effectively simulate Ascending Thoracic Aortic Aneurysms (ATAA), the stress-free configuration must be defined. The Zero Pressure Geometry (ZPG) and the Prestress Tensor (PT) are two of the main approaches to tackle this issue. However, their impact on the numerical results is yet to be analysed. Computed Tomography Angiography (CTA) and Magnetic Resonance Imaging (MRI) data were used to develop patient-specific 2-way FSI frameworks. Three models were developed considering different tissue prestressing approaches to account for the reference configuration and their numerical results were compared. The selected approaches were: (i) ZPG, (ii) PT and (iii) a combination of the PT approach with a regional mapping of material properties (PTCAL). The pressure fields estimated by all models were equivalent. The estimation of Wall Shear Stress (WSS) based metrics revealed good correspondence between all models except the Relative Residence Time (RRT). Regarding ATAA wall mechanics, the proposed extension to the PT approach presented a closer agreement with the ZPG model than its counterpart. Additionally, the PT and PTCAL approaches required around 60% fewer iterations to achieve cycle-to-cycle convergence than the ZPG algorithm. Using a regional mapping of material properties in combination with the PT method presented a better correspondence with the ZPG approach. The outcomes of this study can pave the way for advancing the accuracy and convergence of ATAA numerical models using the PT methodology. •Comparison of tissue prestressing methods on fluid-structure interaction simulations.•The impact of Zero Pressure Geometry (ZPG) and Prestress Tensor (PT) is assessed.•The ZPG and PT algorithms produce similar results regarding aortic hemodynamics.•The PT approach estimates a stiffer mechanical response in the aneurysmal aorta.•Regional mapping of material properties improves agreement with the ZPG approach.