M. Unverdorben et al., First results in an animal model on stents sheathed with a polytetrafluoroethylene membrane., ROFO-F RONT, 173(9), 2001, pp. 836-841
Citations number
23
Categorie Soggetti
Radiology ,Nuclear Medicine & Imaging
Journal title
ROFO-FORTSCHRITTE AUF DEM GEBIET DER RONTGENSTRAHLEN UND DER BILDGEBENDEN VERFAHREN
Objectives: Mechanisms of restenosis after coronary stent implantation incl
ude marked intimal proliferation as well as vascular tissue protrusion thro
ugh the meshes. Thus, stent sheathed with membranes may be an alternative t
o improve the long-term outcome. Methods: Seventeen cylindric serpentine sh
aped 316L stainless steel stents (nominal diameter 3.0 mm, length 15 mm) li
ned and covered by a polytetrafluoroethylene (PTFE) membrane and 10 unsheat
hed devices were implanted into the iliac arteries of 14 New Zealand White
Rabbits for an observation period of 1 - 10, 11 - 20, and 21 - 30 weeks. Af
ter sacrificing the animals, specimens were harvested, fixed in formalin, p
rocessed in paraffin, serially sliced into 5 mum thick preparations, and st
ained (hematoxylin & eosin, elastica von Gieson). Results: The polytetraflu
oroethylene membrane stents increased the vascular lumen significantly (p <
0.04) to 1185.3 - 1620.4 <mu>m compared with the native segments (655.6 +/
- 268.8 mum). In the stainless steel stents the lumen decreased from 1873.1
mum to 719.1 mum. None of the devices penetrated the internal elastic memb
rane. There was no inflammatory vascular reaction. Compared to the native s
egments, the amount of elastic fibres was slightly less (native: 8.9 %, PTF
E: 2.3 - 3.5 %, without PTFE: 1.9 - 5.5 %) whereas the collagen fibres incr
eased marginally (native: 5.1 %, PTFE: 6 - 6.9 %, without PTFE: 6.4 - 8.4 %
). Conclusions: In the rabbit iliac artery, stents sheathed with a micropor
ous polytetrafluoroethylene membrane showed good tissue compatibility with
no restenosis. These results warrant clinical trials.