title: Biocompatibility and performance of the Wallstent and the Wallgraft, Jostent, and Hemobahn stent-grafts in a sheep model.
abstract: OBJECTIVE
  Three recently developed stent-grafts and the Wallstent were compared directly in an ovine animal model with regard to performance and biocompatibility.
  
  
  METHODS
  Three stent-grafts, the Hemobahn (polytetrafluoroethylene [ePTFE]/nitinol), Wallgraft (polyester/Ni-Co-Ti-steel alloy), and Jostent peripheral stent-graft (balloon-expandable ePTFE/stainless steel), and the Wallstent (Ni-Co-Ti-steel alloy), were implanted in sheep iliac arteries (one type of each stent or stent-graft per animal, n = 8). Pre- and postimplantation luminal diameters were measured for each prosthesis and implantation site. Angiography, intravascular ultrasonography (IVUS), and histomorphometric, histologic, and scanning electron microscopic analyses were performed at 3 months.
  
  
  RESULTS
  Early lumen gain, late lumen loss, and patent vessel diameter at angiography were not significantly different. Two stent-grafts had significantly more neointima formation (Hemobahn, 9.88 mm(2) +/- 0.94; Wallgraft, 14.98 mm(2) +/- 0.90) than the other stent-graft (Jostent, 6.52 mm(2) +/- 0.46) and the Wallstent (5.24 mm(2) +/- 0.62; P <.01). Patent lumen area was not significantly different (Hemobahn, 42.57 mm(2) +/- 1.41; Jostent, 39.76 mm(2) +/- 2.04; Wallgraft, 40.22 mm(2) +/- 1.04; Wallstent, 41.64 mm(2) +/- 1.59; P =.57). The Hemobahn had significantly more inflammatory reaction (inflammation score of 0.83 +/- 0.03) than the Jostent (0.58 +/- 0.03), Wallgraft (0.55 +/- 0.04), or Wallstent (0.16 +/- 0.01). Angiography and IVUS demonstrated absence of anastomotic neointima formation. Endothelialization was incomplete and immature for all prostheses.
  
  
  CONCLUSIONS
  The stent-grafts caused a greater degree of neointima formation and inflammatory vessel wall reaction than the bare stent. However, these changes did not interfere with patent lumen areas and occurred in the absence of excessive anastomotic neointima formation.
authors.affiliation: Department of Radiology, University of Vienna, Austria. manfred.cejna@univie.ac.at
authors.forename: Manfred
authors.initials: M
authors.lastname: Cejna
authors.forename: Renu
authors.initials: R
authors.lastname: Virmani
authors.forename: Russel
authors.initials: R
authors.lastname: Jones
authors.forename: Helga
authors.initials: H
authors.lastname: Bergmeister
authors.forename: Christian
authors.initials: C
authors.lastname: Loewe
authors.forename: Maria
authors.initials: M
authors.lastname: Schoder
authors.forename: Mario
authors.initials: M
authors.lastname: Grgurin
authors.forename: Johannes
authors.initials: J
authors.lastname: Lammer
mesh_terms: D000497:Alloys; D000818:Animals; D001672:Biocompatible Materials / Q000009:adverse effects; D001807:Blood Vessel Prosthesis / Q000009:adverse effects; D005260:Female; D007083:Iliac Artery / Q000000981:diagnostic imaging / Q000473:pathology; D007249:Inflammation; D008855:Microscopy, Electron, Scanning; D011091:Polyesters; D011138:Polytetrafluoroethylene; D011859:Radiography; D012756:Sheep; D013193:Stainless Steel; D015607:Stents / Q000009:adverse effects; D017539:Tunica Intima / Q000473:pathology
chemical_list: D000497:Alloys; D001672:Biocompatible Materials; D011091:Polyesters; D013193:Stainless Steel; C013616:nitinol; D011138:Polytetrafluoroethylene