Histopathologic evaluation of an expanded polytetrafluoroethylene- nitinol stent endoprosthesis in canine iliofemoral arteries

Renu Virmani, Frank D. Kolodgie, Michael D. Dake, James H. Silver, Russ M. Jones, Marie Jenkins, David L. Gillespie

Research output: Contribution to journalArticlepeer-review

64 Scopus citations


PURPOSE: The authors assess a new ePTFE-nitinol stent for its long-term patency, healing, and properties of endothelialization. MATERIALS AND METHODS: Adult greyhounds (n = 18) underwent bilateral iliofemoral placement of an endoprosthesis (Hemobahn) consisting of a nitinol stent lined with an ultrathin expanded polytetrafluoroethylene (ePTFE) material. Histologic and quantitative morphometric analyses were performed on devices explanted at 2 weeks and 1, 3, 6, and 12 months. The source of endothelialization was examined in four additional devices modified by sealing either the proximal and distal ends or the entire graft with poly(tetrafluoroethylene-co- hexafluoropropylene) (FEP), a nonporous laminate to prevent potential transgraft endothelial cell migration. RESULTS: Device patency assessed with both intravascular ultrasound and histologic study showed minimal arterial stenosis, irrespective of implant duration. The neointima at less than 3 months consisted of fibrin and inflammatory infiltrate; at later time points, it was composed of mostly smooth muscle cells. Flow surfaces were more than 75% endothelialized by 3 months, which was nearly complete by 6 months. Modified endoprostheses entirely enveloped with FEP resulted in endothelialization of only the proximal and distal ends; the middle regions showed nonocclusive thrombi. Conversely, devices wrapped proximally and distally showed nearly complete endothelialization. CONCLUSIONS: This ePTFE- nitinol endoprosthesis demonstrated long-term patency at up to 1 year after implantation and showed early and nearly complete endothelialization by 6 months. The design promoted rapid endothelialization of flow surfaces, particularly in the midregion of the device possibly by transgraft migration.

Original languageEnglish (US)
Pages (from-to)445-456
Number of pages12
JournalJournal of Vascular and Interventional Radiology
Issue number4
StatePublished - Apr 1999


  • Endothelium
  • Endovascular stent grafts
  • Stents and prostheses

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging
  • Cardiology and Cardiovascular Medicine


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