Simulation of mechanical behavior of temperature-responsive braided stents made of shape memory polyurethanes

• Published in: Journal of biomechanics Vol. 43; no. 4; pp. 632 - 643
• Main Authors: Hyun Kim, Ju, Jin Kang, Tae, Yu, Woong-Ryeol
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 03.03.2010; Elsevier; Elsevier Limited
• Subjects: Biological and medical sciences; Braided stent; Braiding; Computer Simulation; Computer-Aided Design; Computerized, statistical medical data processing and models in biomedicine; Constitutive equations; Constitutive relationships; Deployment simulation; Diseases of the cardiovascular system; Elastic Modulus; Equipment Failure Analysis; Fibers; Finite element analysis; Medical sciences; Models and simulation; Models, Chemical; Physical Medicine and Rehabilitation; Polymers; Polyurethane resins; Polyurethanes - chemistry; Prosthesis Design; Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects); Shape memory; Shape memory polyurethane; Stents; Stress, Mechanical; Studies; Surgical implants; Temperature; Tensile Strength; Thermo-responsive; Deployment simulation; Finite element analysis; Braided stent; Thermo-responsive; Shape memory polyurethane; Temperature; Mechanical properties; Instrumentation therapy; Instrumental dilatation; Modeling; Stent; Geometrical model; Biomechanics; Finite element method; Treatment; Polyurethane; Simulation model; Biomedical engineering
• ISSN: 0021-9290; 1873-2380
• DOI: 10.1016/j.jbiomech.2009.10.032

Abstract Polymeric stents can be considered as an alternative to metallic stents thanks to their lessened incidence of restenosis and controlled deployment. The purpose of this study was to investigate the feasibility of developing a temperature-responsive braided stent using shape memory polyurethane (SMPU) through finite element analysis. It was assumed that braided stents were manufactured using SMPU fibers. The mechanical behavior of SMPU fibers was modeled using a constitutive equation describing their one-dimensional thermal-induced shape memory behavior. Then, the braided stents were analyzed to investigate their mechanical behavior using finite element analysis software, in which the constitutive equation was implemented through a user material subroutine. The diameter of the SMPU fibers and braiding angle were chosen as the design parameters and their values were adjusted to ensure that the mechanical properties of the braided polymer stents match those of metallic stents. Finally, the deployment process of the braided stents inside narrowed vessels was simulated, showing that the SMPU stents can be comfortably implanted while minimizing the overpressure onto the vessel walls, due to their thermo-responsive shape memory behavior.