title: Corrosion resistance, surface evaluation, and geometric design comparison of five self-expanding nitinol stents used in clinical practice.
abstract: OBJECTIVE
  To investigate the corrosion resistance properties of 5 commercially available nitinol stents used to treat peripheral artery disease and compare their surface quality, elemental composition, and geometrical design.
  
  
  METHODS
  Samples of 5 different designs of nitinol peripheral stents [LifeStent (n=4), Philon (n=6), Epic (n=6), S.M.A.R.T. Control (n=7), and Complete SE (n=7)] were examined using stereomicroscopy, environmental scanning electron microscopy, and x-ray photoelectron spectroscopy. Corrosion resistance testing was performed in accordance with ASTM International Standard F2129-08.
  
  
  RESULTS
  Thirteen (43%) of 30 stents corroded during this experiment. Stent fracture was observed in 12 (92%) of these corroded stents. Mean breakdown potentials ranged from 517 to 835 mV (vs. Ag/AgCl) for the Philon, Complete SE, S.M.A.R.T. Control, Epic, and LifeStent models from lowest to highest. A statistically significant difference in breakdown potential was observed between the LifeStent vs. Philon stents (835 vs. 517 mV, p=0.01) and Epic vs. Philon stents (833 vs. 517 mV, p=0.03). Stents with lower breakdown potential and relative breakdown potentials were associated with a higher fracture frequency (Spearman correlation coefficient -0.44, p=0.015 and -0.869, p<0.01, respectively).
  
  
  CONCLUSIONS
  In this in vitro study, corrosion led independently to stent fracture. There is a significant association between lower mean breakdown/relative breakdown potentials and stent fracture.
authors.affiliation: 1 Department of Surgery and.
authors.forename: Jasper W
authors.initials: JW
authors.lastname: Morrison
authors.forename: Matthew H
authors.initials: MH
authors.lastname: Pelletier
authors.forename: Alain
authors.initials: A
authors.lastname: Rives
authors.forename: William R
authors.initials: WR
authors.lastname: Walsh
authors.forename: Jia-Lin
authors.initials: JL
authors.lastname: Yang
authors.forename: Ramon L
authors.initials: RL
authors.lastname: Varcoe
mesh_terms: D000497:Alloys; D003343:Corrosion; D057510:Endovascular Procedures / Q000295:instrumentation*; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D058729:Peripheral Arterial Disease / Q000628:therapy*; D056951:Photoelectron Spectroscopy; D011474:Prosthesis Design; D011475:Prosthesis Failure; D015607:Stents; D013499:Surface Properties
chemical_list: D000497:Alloys; C013616:nitinol