Longitudinal stent deformation (LSD) caused by insufficient longitudinal strength of stent has become one of the serious complications of stent intervention. Although an auxetic stent, as highly promising stent, has already been widely used in the interventional field, its resistance to longitudinal deformation has not yet been studied. In this study, three types of stents were designed and their LSD were studied and compared with conventional stents. Finite element analysis was used to investigate the effects of Poisson's ratio, stent structural design, tensile force application location, circumferential cell number, and expansion diameter on LSD. The results showed that a more pronounced auxetic tendency contributes to enhancing the stent's capability to resist longitudinal deformation. Auxetic stents exhibited superior longitudinal strength compared to conventional stents. Increasing the number of connecting struts was found to enhance longitudinal strength. A cell design featuring a convex hexagonal shape was shown to improve the longitudinal strength of stents. Moreover, an increase of the number of circumferential cells led to an increase of longitudinal strength. It was also observed that the stent ends were more susceptible to longitudinal deformation than the midsection. Additionally, longitudinal strength was found to decrease with the increase of stent expansion diameter. This study may provide insights for the structural design of high-performance stents and rational selection of stents with resistance to LSD.
Shen et al. (Sun,) studied this question.