Modeling Stent-Graft Deployment in Chronic Type B Aortic Dissection: A Patient-Specific Study on the Impact of...

Aortic dissection (AD), particularly type B aortic dissection (TBAD), is a severe vascular condition with complex biomechanical implications that pose challenges for effective treatment. Thoracic endovascular aortic repair (TEVAR) has emerged as the standard approach for acute complicated TBAD; however, its efficacy in chronic cases remains uncertain due to factors such as fibrotic dissection flap and altered aortic wall properties. Current numerical simulations of TEVAR provide valuable insights into stent-graft behavior but lack comprehensive analyses of the effect of variable thickness distributions in patient-specific aortic anatomies and sensitivity of results to procedural factors such as the guiding catheter position. This study presents a finite element-based simulation pipeline to investigate the impact of (i) thickness variations in the aortic wall and dissection flap and (ii) guiding catheter path on the predictive accuracy of TEVAR outcomes in chronic TBAD. Using a virtual catheter technique implemented in Abaqus/Explicit, stent-graft deployment was simulated in a patient-specific model. The model incorporates hexahedral meshing for wall thickness distribution to improve computational efficiency. Quantitative assessment of the model's predictions reveals strong agreement with post-TEVAR CT data when a uniform aortic wall thickness is assumed and the guiding catheter path is reconstructed based on follow-up CT scan. Specifically, the predictions show radial, longitudinal, transverse, and angular deviations of 4.14%  $\pm$  3.25%, 4.75  $\pm$  1.70 mm, 4.29  $\pm$  1.36 mm, and 6.08°  $\pm$  4.22°, respectively. Thickness variations in the dissection flap and aortic wall minimally affect stent-graft positional predictions but significantly influence radius expansion and spatial configuration.