title: Auxetic coronary stent endoprosthesis: fabrication and structural analysis.
abstract: BACKGROUND
  Cardiovascular heart disease is one of the leading health issues in the present era and requires considerable health care resources to prevent it. The present study was focused on the development of a new coronary stent based on novel auxetic geometry which enables the stent to exhibit a negative Poisson's ratio. Commercially available coronary stents have isotropic properties, whereas the vascular system of the body shows anisotropic characteristics. This results in a mismatch between anisotropic-isotropic properties of the stent and arterial wall, and this in turn is not favorable for mechanical adhesion of the commercially available coronary stents with the arterial wall. It is believed that an auxetic coronary stent with inherent anisotropic mechanical properties and negative Poisson's ratio will have good mechanical adhesion with the arterial wall.
  
  
  METHODS
  The auxetic design was obtained via laser cutting, and surface treatment was performed with acid pickling and electropolishing, followed by an annealing process. In vitro mechanical analysis was performed to analyze the mechanical performance of the auxetic coronary stent. Scanning electronic microscopy (SEM) was used to determine the effects of fabrication processes on the topography of the auxetic stent.
  
  
  CONCLUSIONS
  The elastic recoil (3.3%) of the in vitro mechanical analysis showed that the auxetic stent design effectively maintained the luminal patency of the coronary artery. Also, the auxetic coronary stent showed no foreshortening, therefore it avoids the problem of stent migration, by expanding in both the radial and longitudinal directions. By virtue of its synclastic behavior, the auxetic stent bulges outward when it is radially expanded through an inflated balloon.
authors.affiliation: Biomedical Engineering and Sciences Department, School of Mechanical and Manufacturing Engineering, National University of Sciences and Technology (NUST), Islamabad - Pakistan.
authors.forename: Faisal
authors.initials: F
authors.lastname: Amin
authors.affiliation: Biomedical Engineering and Sciences Department, School of Mechanical and Manufacturing Engineering, National University of Sciences and Technology (NUST), Islamabad - Pakistan.
authors.forename: Murtaza Najabat
authors.initials: MN
authors.lastname: Ali
authors.affiliation: Biomedical Engineering and Sciences Department, School of Mechanical and Manufacturing Engineering, National University of Sciences and Technology (NUST), Islamabad - Pakistan.
authors.forename: Umar
authors.initials: U
authors.lastname: Ansari
authors.affiliation: Biomedical Engineering and Sciences Department, School of Mechanical and Manufacturing Engineering, National University of Sciences and Technology (NUST), Islamabad - Pakistan.
authors.forename: Mariam
authors.initials: M
authors.lastname: Mir
authors.affiliation: Experimental Physics Facility, National Center for Physics, Islamabad - Pakistan.
authors.forename: Muhammad Asim
authors.initials: MA
authors.lastname: Minhas
authors.affiliation: Experimental Physics Facility, National Center for Physics, Islamabad - Pakistan.
authors.forename: Wakeel
authors.initials: W
authors.lastname: Shahid
mesh_terms: D016880:Anisotropy; D001807:Blood Vessel Prosthesis; D017076:Computer-Aided Design; D003327:Coronary Disease / Q000503:physiopathology* / Q000601:surgery; D006801:Humans; D016012:Poisson Distribution; D011474:Prosthesis Design / Q000379:methods*; D015607:Stents