title: Experimental investigation of modern and established carotid stents.
abstract: OBJECTIVE
  The design and material determine the mechanical properties of stents. In vitro parameters such as radial force, flexibility and wall adaptation of different stents were investigated in order to obtain evidence for clinical use.
  
  
  METHODS
  A total of 8 stents, including 2 hybrid stents with a combination of closed/open-cell design (Sinus Carotid RX, Cristallo Ideale), 3 closed-cell stents (Adapt, Carotid Wallstent, Xact Carotid) and 3 open-cell stents (Vivexx Carotid, Protégé Rx and Precise) with a diameter of 8 mm and a length of 40 mm, were investigated. The radial force, the bending stiffness of the stent system and of the stent, and the collapse pressure were measured. The wall adjustment of the stents was documented by fluoroscopy and assessed in a step and curve model.
  
  
  RESULTS
  The bending stiffness of the stent systems declined significantly in the expanded state, whereby the Xact Carotid stent showed the highest value (291.1 N/mm2) in contrast to 31.6-39.4 N/mm2 for the Sinus Carotid and Cristallo Ideale. The radial force on expansion of the stents to 7 mm was lowest for the Adapt (0.009 N/mm) and highest for the Precise (0.068 N/mm). The collapse pressure was highest for the Carotid Wallstent (0.48 bar), compared with the other stents (0.1 - 0.2 bar). The best wall adjustment in the curve model was shown by the Precise, the Sinus Carotid Rx and the Vivexx Carotid Stent. The diameter change from 5 to 7 mm was smoothly adapted by the Cristallo Ideale and the Carotid Wallstent. The Adapt showed poor vessel wall adaptation in both step and curved vessels.
  
  
  CONCLUSIONS
  As a result of their design, the Sinus Carotid Rx and the Cristallo Ideale show the best wall adjustment, with comparable radial force and high flexibility, whereby the Cristallo Ideale has the advantage that it has a closed-cell design in the middle third of the stent. The other stents should be taken into consideration with their specifications in individual cases.
  
  
  CONCLUSIONS
  The investigation of carotid stents provides an objective comparison of mechanical properties. Conclusions about the respective optimum uses of stents can be drawn from this. The hybrid stents show a good balance of properties for wide applicability. Citation Format: • Wissgott C, Schmidt W, Behrens P et al. Experimental Investigation of Modern and Established Carotid Stents. Fortschr Röntgenstr 2014; 186: 157 - 165.
authors.affiliation: Institute of Diagnostic and Interventional Radiology/Neuroradiology, Westkuestenklinikum Heide - Academic Teaching Hospital of the Universities of Kiel, Luebeck and Hamburg, Heide.
authors.forename: C
authors.initials: C
authors.lastname: Wissgott
authors.affiliation: Institute for Biomedical Engineering, University of Rostock, Rostock-Warnemünde.
authors.forename: W
authors.initials: W
authors.lastname: Schmidt
authors.affiliation: Institute for Biomedical Engineering, University of Rostock, Rostock-Warnemünde.
authors.forename: P
authors.initials: P
authors.lastname: Behrens
authors.affiliation: Institute for Biomedical Engineering, University of Rostock, Rostock-Warnemünde.
authors.forename: C
authors.initials: C
authors.lastname: Brandt
authors.affiliation: Institute for Biomedical Engineering, University of Rostock, Rostock-Warnemünde.
authors.forename: K P
authors.initials: KP
authors.lastname: Schmitz
authors.affiliation: Institute of Diagnostic and Interventional Radiology/Neuroradiology, Westkuestenklinikum Heide - Academic Teaching Hospital of the Universities of Kiel, Luebeck and Hamburg, Heide.
authors.forename: R
authors.initials: R
authors.lastname: Andresen
mesh_terms: D001807:Blood Vessel Prosthesis; D019245:Compressive Strength; D003198:Computer Simulation; D055119:Elastic Modulus; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D008962:Models, Theoretical; D011312:Pressure; D015607:Stents; D013314:Stress, Mechanical; D013718:Tensile Strength