A novel double arrowhead auxetic coronary stent

Abstract

A stent implantation is a standard medical procedure for treating coronary artery diseases. Over the years, various different designs have been explored for the stents which come with a range of limitations, including late in-stent restenosis (due to low radial strength), foreshortening, radial recoil, etc. Contrary, stents with auxetic design, characterized by a negative Poisson's ratio, display unique deformation characteristics that result in enhanced mechanical properties in terms of its radial strength, radial recoil, foreshortening, and more. In this study, we have analysed a novel double arrowhead (DA) auxetic stent that aims to overcome the limitations associated with traditional stents, specifically in terms of radial strength, foreshortening, and radial recoil. The parametric analysis was done initially on the DA's unit ring structure to optimize the design by evaluating the effect of three design parameters (angle, amplitude, and width) on the mechanical characteristics (radial strength and radial recoil) using finite element analysis. The width of the strut was found to be the primary determinant of the stent structure's properties. Consequently, the angle and width were found to have the least effect on altering the stent's mechanical properties. After performing the parametric analysis, optimal design factors were selected to design the full-length DA auxetic stent. The mechanical characteristics of the DA auxetic stent were assessed and compared in a case study with the Cypher™ commercial stent. The radial strength of DA auxetic stent was found to be 7.26 N/mm, which is more than double the Cypher™ commercial stent's radial strength. Additionally, the proposed stent possesses reduced radial recoil property and completely eliminates the stent foreshortening issue, which shows the superior mechanical properties of the proposed auxetic stent and its potential as a promising candidate for future stent designs.