A modeling framework for computational simulations of thoracic endovascular aortic repair

Abstract

Thoracic endovascular aortic repair (TEVAR) is a minimally invasive treatment for thoracic aortic conditions including aneurysms and is associated with a number of postoperative stent graft related complications. Computational simulations of TEVAR have the potential to predict surgical outcomes and complications preoperatively. When using simulations for stent graft design and prediction of complications in a population, it is difficult to generalize patient-specific TEVAR computational models due to patient variability. This study proposes a novel modeling framework for creating realistic population-based computational models of TEVAR focused on aneurysms that allow for developing various clinically relevant geometric configurations and scenarios that are not easily attainable with limited patient data. The framework includes a methodology for developing population-based thoracic aortic geometries and defining agedependent aortic tissue material models, as well as detailed steps and boundary conditions for finite element modeling of stent graft deployment during TEVAR.

Validation and Verification of High-Fidelity Simulations of Thoracic Stent-Graft Implantation

“…However, the V&V process on the TEVAR procedure simulations is not always done to assess the credibility of the in silico results. 37 To the best of the authors’ knowledge, the finite element TEVAR simulations were never compared at different timing during the deployment with an ad-hoc experimental setup. In our framework, the aorta was 3D printed with a rigid material 21 to prevent numerical uncertainties related to the arterial wall mechanical properties.…”

On the necessity to include arterial pre-stress in patient-specific simulations of minimally invasive procedures

“…Several studies in the literature replicated the two mentioned endovascular procedures in patient-specific anatomies with finite element (FE) simulations to investigate the outcomes and risks of the procedures (about 20 papers in the last 2 years). However, only a few TEVAR studies consider aortic wall pre-stress (Desyatova et al 2020 ; Concannon et al 2021 ; Kan et al 2021 ; Shahbazian et al 2022 ), while, to the best of our knowledge, studies accounting for aortic root pre-stress in TAVI procedure simulations are missing. Concannon et al ( 2021 ) conducted a study comparing the outcomes of TEVAR procedures in patients of different ages.…”

“…This iterative process ended when the nodal displacement resulting from the pressurization was lower than the CTA in-plane resolution, meaning that the wall stress state was in equilibrium with the external load. Shahbazian et al ( 2022 ) incorporated the pre-stress in idealized thoracic aortic models by pressurizing the segmented aortic geometry up to the diastolic pressure, then subtracted the resulting nodal displacements incrementally from the initial geometry until the residual difference between the current and initial configurations was minimized. Pre-stretch in addition to pre-stress was only considered by Desyatova et al ( 2020 ).…”

Proper sizing of aortic endografts from bench to bedside

“…Taking this a step further, some investigators have used computational modeling to determine the effects of aortic configuration (ie, aortic curvature, arch angle) on thoracic endovascular aortic repair outcomes. 4 …”