Optimizing the deformation behavior of stent with nonuniform Poisson's ratio distribution for curved artery. (December 2018)

• Record Type: Journal Article
• Authors: Han, Yafeng; Lu, Wenfeng
• Is Part Of: Journal of the mechanical behavior of biomedical materials. Volume 88(2018)
• Page Start: 442
• Page End: 452
• Publication Date: 2018-12
• Subjects: Ring-and-link stent structure -- Deformation behavior -- Negative Poisson's ratio -- Nonuniform structure -- Curved arteries -- In-stent restenosis; Biomedical materials -- Periodicals; Biomedical materials -- Mechanical properties -- Periodicals; Biomedical materials; Biomedical materials -- Mechanical properties; Periodicals; Electronic journals; 610.28
• DOI: 10.1016/j.jmbbm.2018.09.005
• Languages: English
• ISSNs: 1751-6161

Abstract

Abstract: Stent implantation at a highly curved artery has always been a challenge, considering the relatively high chance of in-stent restenosis (ISR) caused by severe straightening effect and high strain energy over the vessel wall. In this paper, a novel optimization based design method was proposed to manipulate the deformation behavior of the common ring-and-link stent. By changing the location of the connection point between rings and links, traditional ring-and-link structure was modified to achiever tunable Poisson's ratio (PR). With the nonuniform cellular structure design method proposed in a previous study, PR distribution of the stent structure was optimized to achieve the desired curvature. As a result, the obtained stent structure with nonuniform PR could perfectly fit into the curved artery after expansion, without causing any obvious vessel straightening. To validate the proposed method, two different vessel models were introduced. Firstly, a short vessel with a constant curvature was set as the design objective, and both numerical and experimental tests were conducted. Further, a patient-specific vessel was applied. Both test results showed that optimized stents would cause much smaller vessel straightening. Moreover, vessels stented by the optimized structures had much lower stress concentration and strain energy. All those properties will decrease the possibility of ISR significantly. Graphic abstract: Highlights: The newly designed stent structure can perfectly fit into the outline of the curved artery. Nonuniform Poisson's ratio distribution was easily achieved by modifying the traditional ring-and-link structure. Smooth transition between unit cells with different Poisson's ratio was maintained for a better deformation curvature. Much lower strain energy and stress concentration was applied on the vessel wall.