Duca, F. | bioRxiv Science

bioRxiv2026

Predicting post-TEVAR endoleaks: a pre-operative hemodynamic risk factor from patient-specific Fluid-Structure Interaction simulations

Thoracic Endovascular Aortic Repair (TEVAR) is a minimally invasive procedure for the treatment of thoracic aortic pathologies, such as Thoracic Aortic Aneurysm (TAA). Computational simulations can provide valuable insights into TEVAR outcomes and complications prior to surgery, making them a useful tool in the procedural planning. In this work, Fluid-Structure Interaction (FSI) computational simulations are carried out in ten pre-TEVAR patient-specific TAA cases, for which post-TEVAR outcomes are known, to quantify the hemodynamic drag forces acting on the aortic wall. Based on these results, this study proposes a new risk factor R to predict the occurrence of type I and III endoleaks. The patient cohort is divided in a calibration set, used to associate specific R values with three different risk levels, and a validation set, to test the risk factor efficacy. Based on the risk factor values obtained for the calibration set, R[≤] 0.33 is associated with low risk of endoleak formation, 0.33 < R[≤] 0.67 with moderate risk, and R > 0.67 with high risk. Once it is applied to the validation set,the risk factor is able to predict the formation of a type Ia endoleak. The risk factor proposed in this work is capable of identifying all the endoleak cases analysed, as well as conditions known to increase the risk of TEVAR complications. This study represents a preliminary attempt to determine whether pre-TEVAR hemodynamics can effectively predict post-TEVAR complications and thereby aid clinicians in the pre-operative planning.

bioengineering↗

bioRxiv2024

Computational analysis to assess hemodynamic forces in descending thoracic aortic aneurysms

Descending Thoracic Aortic Aneurysm (DTAA) is a life-threatening disorder, defined as a localized enlargement of the descending portion of the thoracic aorta. In this context, we develop a Fluid-Structure Interaction (FSI) computational framework, with the inclusion of a turbulence model and different material properties for the healthy and the aneurysmatic portions of the vessel, to study the hemodynamics and its relationship with DTAA. We first provide an analysis on nine ideal scenarios, accounting for different aortic arch types and DTAA ubications, to study changes in blood pressure, flow patterns, turbulence, wall shear stress, drag forces and internal wall stresses. Our findings demonstrate that the hemodynamics in DTAA is profoundly disturbed, with the presence of flow recirculation, formation of vortices and transition to turbulence. In particular, configurations with a more steep aortic arch exhibit a more chaotic hemodynamics. We notice also an increase of pressure values for configurations with less steep aortic arch and of drag forces for configurations with distal DTAA. Secondly, we replicate our analysis for three patient-specific cases (one for type of arch) obtaining conforting results in terms of accordance with the ideal scenarios. Finally, in a very preliminary way, we try to relate our findings to possible stent-graft migrations after TEVAR procedure to provide predictions on the post-operative state. KEY POINTSO_LIThis study employs computational methods to assess hemodynamic forces in descending thoracic aortic aneurysms; C_LIO_LIWe consider ideal cases by varying aortic arch type and aneurysm location; C_LIO_LIOur results show: chaotic hemodynamics for steep aortic arches; increase of pressure values for less steep aortic arches; high risk of plaque in the sac for proximal aneurysms and in the neck for distal aneurysms; C_LIO_LIWe analyse also 3 patient-specific cases, confirming the major outcomes found for the ideal cases; C_LIO_LIWe try to suggest how our pre-operative findings may be put in relation to assess the risk of stent-graft migration of a possible TEVAR procedure. C_LI

bioengineering↗