title: Thin film nitinol covered stents: design and animal testing.
abstract: Interventionalists in many specialties have the need for improved, low profile covered stents. Thin films of nitinol (<5-10 microns) could be used to improve current covered stent technology. A "hot target" sputter deposition technique was used to create thin films of nitinol for this study. Covered stents were created from commercially available balloon-inflatable and self-expanding stents. Stents were deployed in a laboratory flow loop and in four swine. Uncovered stent portions served as controls. Postmortem examinations were performed 2-6 weeks after implantation. In short-term testing, thin film nitinol covered stents deployed in the arterial circulation showed no intimal proliferation and were easily removed from the arterial wall postmortem. Scanning electron microscopy showed a thin layer of endothelial cells on the thin film, which covered the entire film by 3 weeks. By contrast, significant neointimal hyperplasia occurred on the luminal side of stents deployed in the venous circulation. Extremely low-profile covered stents can be manufactured using thin films of nitinol. Although long-term studies are needed, thin film nitinol may allow for the development of low-profile, nonthrombogenic covered stents.
authors.affiliation: Division of Pediatric Cardiology, Mattel Children's Hospital at UCLA, Los Angeles, California, USA.
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Levi
authors.forename: Ryan J
authors.initials: RJ
authors.lastname: Williams
authors.forename: Jasen
authors.initials: J
authors.lastname: Liu
authors.forename: Saar
authors.initials: S
authors.lastname: Danon
authors.forename: Lenka L
authors.initials: LL
authors.lastname: Stepan
authors.forename: Mohanchandra K
authors.initials: MK
authors.lastname: Panduranga
authors.forename: Michael C
authors.initials: MC
authors.lastname: Fishbein
authors.forename: Greg P
authors.initials: GP
authors.lastname: Carman
mesh_terms: D000497:Alloys; D015906:Angioplasty, Balloon, Coronary; D000818:Animals; D001013:Aorta, Thoracic; D001696:Biomechanical Phenomena; D001698:Biomedical Engineering; D002152:Calorimetry, Differential Scanning; D020099:Coated Materials, Biocompatible; D004867:Equipment Design; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D015607:Stents; D013499:Surface Properties; D034421:Sus scrofa; D013718:Tensile Strength; D014682:Vena Cava, Inferior; D014683:Vena Cava, Superior
chemical_list: D000497:Alloys; D020099:Coated Materials, Biocompatible; C013616:nitinol