Healing response of normal canine aorta and iliac artery to a nitinol stent encapsulated in carbon-lined ePTFE.
OBJECTIVE
To evaluate the healing response of normal canine arteries to a self-expanding nitinol stent encapsulated in carbon-lined expanded polytetrafluoroethylene (ePTFE).


METHODS
Twenty-eight dogs were divided into aortic (n = 18) or iliac (n = 10) groups. In the latter, 2 animals were assigned to implantation intervals of 7, 30, and 90 days, respectively; 4 were designated for 180-day implantation. Half of the animals in each subgroup received a second overlapping stent-graft in one iliac artery. In the aortic cohort, 6 animals were assigned to the 180-day implantation group (2 with dual devices) and 3 to each of the others (1 dual implantation in each group). The devices were evaluated with angiography and intravascular ultrasound at implantation and explantation. After harvesting and gross examination, the specimens were examined microscopically and with scanning electron microscopy.


RESULTS
The 49 implanted devices (24 aortic and 25 common iliac) were all widely patent at explantation, save for 2 iliac stents that had moderate (<40%) stenosis. No neointima was present at the 7-day interval. All stents were covered by thin neointima (<150 microm) at 30 days. At 180 days, an endothelial lining was present in the proximal and distal segments of all stents; in 4 of the 6 aortic stents, this endothelial lining was complete, whereas none of the iliac devices had endothelium in the midsegment at 180 days. At 1 year, 2 of the aortic specimens had an incomplete endothelial lining, whereas the lining was complete in the third. There was no evidence of stent-graft migration or inflammation associated with any device.


CONCLUSIONS
The carbon-lined ePTFE-encapsulated stent is a novel approach to arterial stenting. The progressive endothelialization and lack of inflammatory reaction may provide improved long-term patency. Further study of this stent-graft design is warranted.
Woody
J D
JD
Division of Vascular Surgery, Harbor-UCLA Medical Center, Torrance, California 90509, USA.
Nishanian
G
G
Kopchok
G E
GE
Kim
N I
NI
Donayre
C E
CE
White
R A
RA
D000497:Alloys / Q000494:pharmacology*; D000792:Angiography; D000818:Animals; D001011:Aorta / Q000601:surgery*; D004285:Dogs; D004869:Equipment Safety; D005260:Female; D007083:Iliac Artery / Q000601:surgery*; D008297:Male; D008855:Microscopy, Electron, Scanning; D023421:Models, Animal; D011138:Polytetrafluoroethylene / Q000494:pharmacology*; D019919:Prosthesis Implantation / Q000295:instrumentation; D015607:Stents; D013995:Time; D013997:Time Factors; D018084:Ultrasonography, Interventional; D014654:Vascular Patency / Q000187:drug effects; D014945:Wound Healing / Q000187:drug effects / Q000502:physiology*
D000497:Alloys; C013616:nitinol; D011138:Polytetrafluoroethylene