Patients with blunt traumatic thoracic aortic injury treated with TEVAR present increased flow dynamics alterations and pulse wave velocity: a 4D flow CMR study

Abstract

Background Thoracic endovascular aortic repair (TEVAR) is widely used for the treatment of blunt traumatic thoracic aortic injuries. Aortic flow dynamics and mechanical implications of this intervention are poorly investigated and may be of particular interest in the long-term follow-up of these mostly young patients. Purpose To assess whether the presence of TEVAR in a cohort of otherwise healthy subjects was related to dilation of the proximal aorta or increase in aortic stiffness and flow alterations. Methods Nineteen patients who underwent TEVAR implantation after a traumatic injury of the thoracic descending aorta (DAo) (10.0±6.1 years from intervention) and 44 healthy volunteers (HV) underwent 4D flow CMR to compute ascending aorta (AAo) pulse wave velocity (PWV), a marker of aortic stiffness, systolic flow reversal ratio (SFRR), quantifying backward flow during systole and in-plane rotational flow (IRF), measuring in-plane strength of helical flow. IRF and SFRR were assessed at 20 planes between the sinotubular junction and the mid thoracic DAo. Aortic diameters were measured using double-oblique cine CMR. Results Patients with TEVAR and HV did not differ in age, sex, body surface area, blood pressure and DAo diameter distal to TEVAR (Table). However, TEVAR patients presented larger diameters at the sinus of Valsalva and AAo, increased AAo PWV and strong flow alterations: IRF was reduced from the distal AAo to the proximal DAo, while SFRR was increased in the whole thoracic aorta (Figure). Conclusions In patients with blunt traumatic thoracic aortic injury treated with TEVAR the aorta proximal to TEVAR is dilated, stiffer and present potentially pathogenic flow conditions. Longitudinal studies are needed to assess whether these alterations have prognostic value and may improve clinical prevention and management of these patients. Figure 1. IRF and SFRR in healthy vs TEVAR Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): This study has been funded by Instituto de Salud Carlos III, Spanish Ministry of Science and Innovation (PI19/01480). Guala A. received funding from the Spanish Ministry of Science, Innovation and Universities (IJC2018-037349-I).

Impact of thoracic endovascular aortic repair on aortic biomechanics: Integration of in silico and ex vivo analysis using porcine model

“…The developed experimental framework allows to measure the PWV and the corresponding results highlight that the presence of the stent‐graft induces an increase of PWV underlining the stiffening of the aortic structure. Obtained experimental results confirm the evidence found in literature 18 showing that the TEVAR treatment increase the PWV. In addition, the mechanical behavior of the arterial tissue is analyzed through the uniaxial tensile test of aortic porcine samples taken from different regions.…”

“…Moved from such considerations, several studies have exploited 3D analysis of in vivo medical images before 14 and after TEVAR 15,16 in order to quantify how the implantation of TEVAR endografts modifies the conformation and compliance of the repaired aorta, changing the geometry and dynamic motion of the implant site as well as adjacent regions of the aorta 17 . Accordingly, the in vivo aortic flow measurements before and after TEVAR have been performed using 4D flow MRI to assess the hemodynamic impact of endovascular treatment 18 . Alongside the in vivo measurement, engineering tool has been proved as effective to provide useful clinical insight for medical treatments 19,20 .…”

“…17 Accordingly, the in vivo aortic flow measurements before and after TEVAR have been performed using 4D flow MRI to assess the hemodynamic impact of endovascular treatment. 18 Alongside the in vivo measurement, engineering tool has been proved as effective to provide useful clinical insight for medical treatments. 19,20 In fact, in silico, in vitro, and ex vivo models have been proposed to investigate various aspects of TEVAR biomechanics.…”

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

“…A reduction in vorticity in the aorta has been associated with promoting aortic growth and dilation (Gallo et al, 2012; Guala et al, 2019; Stokes et al, 2023a). The IRF metric has been found to drastically reduce after TEVAR in 19 patients (Guala et al, 2020). In the present study, the IRF was overpredicted in S1 compared to S2 by up to 60%, which would indicate higher risks of rupture and would be misleading (Gil-Sala et al, 2021).…”