During TEVAR, a 28–28-150 mm Medtronic Valiant SG (Medtronic Vascular, Santa Rosa, California) with proximal bare metal stent was implanted. The SG geometry was created in Solidworks (Dassault Systèmes, France) following the dimension and specification of the Valliant product which consists of a Nitinol stent scaffold and polyethylene terephthalate (PET) fabric graft (Fig. 2a). The Nitinol stent was meshed into linear hexahedral elements with reduced integration (C3D8R) in Abaqus®. A superelastic material property was used, to reproduce the mechanical behaviour of Nitinol with parameters shown in Table 1 (Kleinstreuer et al. 2008 (link)). PET fabric graft was modelled as a tube with 0.1 mm thickness and meshed into membrane elements with reduced integration (M3D4R). The material property of PET fabric was simplified by assuming it as an isotropic elastic material with parameters taken from the same study (Kleinstreuer et al. 2008 (link)).

Summary of the steps in the simulation of stent-graft (SG) deployment and model variations. a The 28–28-150 mm Medtronic Valiant SG was used in TEVAR procedure and was covered by the virtual sheath. b The SG was compressed by the virtual sheath to its crimped state. c A curved tube opened up the local narrowing in the compressed true lumen. d The SG was delivered and deployed at the targeted position. e overall workflow and model variations

Superelastic material parameters for Nitinol (Kleinstreuer et al. 2008 (link))

Austenite elastic modulus \documentclass[12pt]{minimal}
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\begin{document}$${E}_{\mathrm{A}}$$\end{document}EA, MPa		51,700
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\begin{document}$${\nu }_{\mathrm{A}}$$\end{document}νA		0.3
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\begin{document}$${E}_{\mathrm{M}}$$\end{document}EM, MPa		47,800
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\begin{document}$${\nu }_{\mathrm{M}}$$\end{document}νM		0.3
Transformation strain0.063
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\begin{document}$${\sigma }_{\mathrm{L}}^{\mathrm{s}}$$\end{document}σLs, MPa		600
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\begin{document}$${\sigma }_{\mathrm{L}}^{E}$$\end{document}σLE, MPa		670
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\begin{document}$${\sigma }_{\mathrm{U}}^{\mathrm{s}}$$\end{document}σUs, MPa		288
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\begin{document}$${\sigma }_{\mathrm{U}}^{\mathrm{E}}$$\end{document}σUE, MPa		254
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\begin{document}$${\sigma }_{\mathrm{CL}}^{\mathrm{S}}$$\end{document}σCLS, MPa		900
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\begin{document}$$T$$\end{document}T, ℃		37
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\begin{document}$$\rho$$\end{document}ρ, g/cm3		6.5
The Nitinol stent and PET fabric graft were then assembled together by using the tie constraint which prevents sliding or separation of the two components. A tubular surface with a diameter of 29 mm was created outside of the SG and meshed into surface elements (SMF3D4R); this represented the virtual delivery sheath and was employed to crimp and deliver the SG into the aortic dissection.
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