Model-Based Fluid-Structure Interaction Approach for Evaluation of Thoracic Endovascular Aortic Repair Endograft Length in Type B Aortic Dissection

Abstract

Thoracic endovascular aortic repair (TEVAR) is a commonly performed operation for patients with type B aortic dissection (TBAD). The goal of TEVAR is to cover the proximal entry tear between the true lumen (TL) and the false lumen (FL) with an endograft to induce FL thrombosis, allow for aortic healing, and decrease the risk of aortic aneurysm and rupture. While TEVAR has shown promising outcomes, it can also result in devastating complications including stroke, spinal cord ischemia resulting in paralysis, as well as long-term heart failure, so treatment remains controversial. Similarly, the biomechanical impact of aortic endograft implantation and the hemodynamic impact of endograft design parameters such as length are not well-understood. In this study, a fluid-structure interaction (FSI) computational fluid dynamics (CFD) approach was used based on the immersed boundary and Lattice–Boltzmann method to investigate the association between the endograft length and hemodynamic variables inside the TL and FL. The physiological accuracy of the model was evaluated by comparing simulation results with the true pressure waveform measurements taken during a live TEVAR operation for TBAD. The results demonstrate a non-linear trend towards increased FL flow reversal as the endograft length increases but also increased left ventricular pulsatile workload. These findings suggest a medium-length endograft may be optimal by achieving FL flow reversal and thus FL thrombosis, while minimizing the extra load on the left ventricle. These results also verify that a reduction in heart rate with medical therapy contributes favorably to FL flow reversal.

Direct 0D‐3D coupling of a lattice Boltzmann methodology for fluid–structure aortic flow simulations

“…As can be observed, results are in very good agreement with those of Huang and Sung 56 (which are overlaid in red dots). For further validations on other configurations of the complete immersed boundary FSI solver employed in this work, the reader is referred elsewhere 45,52,74 …”

“…For further validations on other configurations of the complete immersed boundary FSI solver employed in this work, the reader is referred elsewhere. 45,52,74 3.1.4 | The complete FSI solver coupled to the 0D LV-elastance heart model…”

Patient-specific compliant simulation framework informed by 4DMRI-extracted Pulse Wave Velocity: Application post-TEVAR

“…CFD simulations are beneficial in the context of TEVAR to assess the impact of compliance mismatch introduced by endografts. Fluid-structure interaction (FSI) has traditionally been used for patient-specific simulations of TEVAR procedures, for example, to study their impact on cardiac remodelling and left ventricular afterload (Van Bakel et al, 2019) or the flow reversal due to the rigidity and length of the endograft (Aghilinejad et al, 2022) and their impact on left ventricular afterload. However, FSI is computationally costly and often based on literature values of elastic or anisotropic tissue data, as in vivo data are barely accessible (Wang et al, 2023) or impossible to obtain.…”

Stress Load and Ascending Aortic Aneurysms: An Observational, Longitudinal, Single-Center Study Using Computational Fluid Dynamics

“…In the last decade, some review articles have discussed the use of computational fluid dynamics (CFD) to enhance the understanding of hemodynamic patterns in cardiovascular disease [ 16 , 17 ]. In this context, the employment of CFD to investigate aortic diseases [ 18 , 19 , 20 , 21 , 22 , 23 , 24 ], particularly in aneurysmatic ascending aortas [ 25 , 26 ], has been the subject of numerous studies. Current evidence shows that employing CFD for flow analysis in healthy or aneurysmal aortas can contribute to understanding disease etiology by providing insights into the fields of velocity, shear stress, vorticity and identification of recirculation regions [ 22 ].…”