Mechanical characterizations of braided composite stents made of helical polyethylene terephthalate strips and NiTi wires.

Pengfei Dong,Linxia Gu,Meiwen An,Xinwei Han,Changchun Zhou,Zhiqiang Li,Qingli Zheng

doi:10.1515/ntrev-2019-0016

Abstract

The novel braided composite stent (BCS), woven with both nitinol wires and polyethylene terephthalate (PET) strips, were characterized and compared with the braided nitinol stent in the same weaving pattern. Finite element models simulating the stent compression and bending were developed to quantify its radial strength and longitudinal flexibility. The interaction between the nitinol wires and the PET strips were also delineated. Results showed that the PET strips enforced more constrains on the BCS and thus enhance its radial strength especially at a larger compression load. The longitudinal flexibility of the BCS was less sensitive to the presence of the PET strips. This work suggested that the novel design of the BCS could acquire the advantage of a covered stent without compromising its mechanical performance. The fundamental understanding of the braided composite stent will facilitate a better device design.

Highlights

The novel braided composite stent (BCS), woven with both nitinol wires and polyethylene terephthalate (PET) strips, were characterized and compared with the braided nitinol stent in the same weaving pattern
The longitudinal flexibility of the BCS was less sensitive to the presence of the PET strips
The stress or strain distribution patterns of BCS were different with the ones of Braided nitinol stents (BNS)

Summary

Introduction

Abstract: The novel braided composite stent (BCS), woven with both nitinol wires and polyethylene terephthalate (PET) strips, were characterized and compared with the braided nitinol stent in the same weaving pattern. Compared to a bare metallic stent, the covered stent is harder to maneuver through tortuous anatomy without the risk of kinking and migration [6, 7] This led to undesired vessel patency as well as tissue damage and increase incidence of limb thrombosis [8]. A braided composite stent (BCS) woven using PET strips and nitinol (NiTi) wires was proposed to improve the radial strength as well as the flexibility of a BNS [9]. Three-dimensional models of the BCS and the corresponding BNS in the same weaving pattern were developed to evaluate and compare their radial strength and flexibility. Quantitative evaluation of the mechanical performance of the BCS and its underlying mechanisms could facilitate an optimal design of the stent

Materials and methods

Results

Discussions