Thin film nitinol covered stents: design and animal testing

ASAIO J. 2008 May-Jun;54(3):221-6. doi: 10.1097/MAT.0b013e31816b43b0.

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.

MeSH terms

  • Alloys*
  • Angioplasty, Balloon, Coronary
  • Animals
  • Aorta, Thoracic
  • Biomechanical Phenomena
  • Biomedical Engineering
  • Calorimetry, Differential Scanning
  • Coated Materials, Biocompatible*
  • Equipment Design
  • Materials Testing
  • Microscopy, Electron, Scanning
  • Stents*
  • Surface Properties
  • Sus scrofa
  • Tensile Strength
  • Vena Cava, Inferior
  • Vena Cava, Superior

Substances

  • Alloys
  • Coated Materials, Biocompatible
  • nitinol