Tissue response to covered Wallstents.
OBJECTIVE
To evaluate and compare the healing response related to two types of graft-covered Wallstents (WSs) and an uncovered WS in the canine iliac artery.


METHODS
Eight bare mesh WSs, 10 polyethylene terephthalate interbraided WSs (PET-WSs), and six polytetrafluoroethylene covered WSs (ePTFE-WSs) were placed in the iliac arteries of 12 dogs. Arteriograms were obtained before and after implantation and at explantation. Devices were explanted at 1 month (n = 8), 3 months (n = 6), and 6 months (n = 10) and sent for histologic study.


RESULTS
One ePTFE-covered stent-graft was found to be thrombosed at 3 months; the remaining 23 of 24 implants remained patent to the time of explantation. The WS and ePTFE-WS both generated a uniform myointimal cell response without inflammation. The PET-WS induced a fibrous luminal response with substantial foreign body-type inflammatory reaction around the PET fibers. Although neointima associated with the PET-WS appeared thicker than that associated with either the ePTFE-WS or the bare WS, none of the patent implants developed greater than 50% angiographic narrowing.


CONCLUSIONS
The PET-WS induced chronic inflammation, a response not seen with either the WS or ePTFE-WS. This may explain the occurrence of pain and/or fever in human studies of arterial PET endoluminal stent-grafts. Patency for all three implants was excellent in this model.
Dolmatch
B L
BL
Department of Radiology, Cleveland Clinic Foundation, OH 44195, USA.
Dong
Y H
YH
Trerotola
S O
SO
Hunter
D W
DW
Brennecke
L H
LH
LaBounty
R
R
D000818:Animals; D004285:Dogs; D005549:Foreign-Body Reaction / Q000209:etiology* / Q000473:pathology; D007083:Iliac Artery / Q000473:pathology; D011138:Polytetrafluoroethylene; D015607:Stents; D017539:Tunica Intima / Q000473:pathology; D014654:Vascular Patency / Q000502:physiology
D011138:Polytetrafluoroethylene