Influence of fatigue stress on the radial strength of polymeric braided vascular stents

Abstract

AbstractMetallic stents have been largely used over the last decades to treat vascular diseases like coronary artery or peripheral vessel stenosis. Although they remain the gold standard for vascular treatment, they are subjected to in‐vivo complications such as corrosion, structural failure, fractures, and re‐stenosis due especially to the material which is used. Polymer material being less rigid than metallic material could be a potential solution and would help limiting these issues especially in peripheral vessels where flexibility is required. Among polymeric materials, polyethylene terephthalate (PET) has been used to develop stents of this study, since its biocompatibility has already been proven especially in the field of cardiovascular applications. Moreover, to guarantee flexibility, braiding technology has been used to manufacture the samples. The goal of this work was to evaluate PET‐braided stents behavior under accelerated fatigue up to 105 cycles. The effect of fatigue on the radial compression strength was then investigated and the material surface was examined by SEM to identify locations of structural failure. The effect of the different manufacturing parameters (braiding angle, braiding pattern, stent diameter, and wire diameter) on the fatigue behavior was also assessed. Results show that stents have a good elastic recovery of their diameters after fatigue despite the friction that occurred between the filaments. Moreover, fatigue loading induces radial strength loss in all stents. However, this loss varies according to the stent design. In addition, no wire fracture has been reported. It comes out from the study that PET‐braided stents show suitable mechanical behavior over accelerated fatigue loading up to 105 cycles and that their braiding parameters have a huge impact on their performances.