Biocompatibility and performance of the Wallstent and the Wallgraft, Jostent, and Hemobahn stent-grafts in a sheep model.
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.
Cejna
Manfred
M
Department of Radiology, University of Vienna, Austria. manfred.cejna@univie.ac.at
Virmani
Renu
R
Jones
Russel
R
Bergmeister
Helga
H
Loewe
Christian
C
Schoder
Maria
M
Grgurin
Mario
M
Lammer
Johannes
J
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
D000497:Alloys; D001672:Biocompatible Materials; D011091:Polyesters; D013193:Stainless Steel; C013616:nitinol; D011138:Polytetrafluoroethylene