A new polymer concept for coating of vascular stents using PTFEP (poly(bis(trifluoroethoxy)phosphazene) to reduce thrombogenicity and late in-stent stenosis.
OBJECTIVE
We sought to evaluate the new polymer PTFEP (poly(bis(trifluoroethoxy)phosphazene) for (1) its ability to reduce thrombogenicity and late in-stent stenosis and (2) its effect on endothelialization in a rabbit iliac artery model.


METHODS
Nanocoated ( approximately 50 nm) and bare stainless-steel stents were implanted bilaterally in the iliac arteries of 30 New Zealand White rabbits (1, 4, 8, 12, and 16 weeks follow-up) and evaluated by angiography, light, and scanning electron microscopy.


RESULTS
Bilateral stent placement was successful in 27 of 30 rabbits. Thrombus depositions occurred in none of the 27 coated but in 4 of the 27 bare stents (P=0.037). A normal angiogram was obtained in 18 of 22 coated stents at risk for restenosis (follow-up >or=4 weeks) but only in 13 of 22 bare stents (P=0.023). Marked restenosis (luminal loss >30%) was found in 6 bare stents (P=0.011) but not in any coated stents. The neointima was 47.7-73.9 mum on coated and 66.9-115.2 mum on bare stents (statistically significant at 4, 8, and 16 weeks). Scanning electron microscopy detected full endothelialization in all stents from 4 weeks on (22 stents in both groups).


CONCLUSIONS
PTFEP nanocoating successfully showed thromboresistance and reduced late in-stent stenosis. Endothelialization was equal in both stent types. Studies in more human-like models and human feasibility studies in human arteries are encouraged.
Richter
Goetz M
GM
Department of Diagnostic Radiology, Institute for Applied Physical Chemistry, University Heidelberg, Heidelberg, Germany. goetz_richter@med.uni-heidelberg.de
Stampfl
Ulrike
U
Stampfl
Sibylle
S
Rehnitz
Christoph
C
Holler
Susann
S
Schnabel
Philip
P
Grunze
Michael
M
D000818:Animals; D006965:Hyperplasia; D007083:Iliac Artery; D008297:Male; D008855:Microscopy, Electron, Scanning; D009943:Organophosphorus Compounds; D011108:Polymers; D011474:Prosthesis Design; D011817:Rabbits; D013193:Stainless Steel; D015607:Stents; D013927:Thrombosis / Q000517:prevention & control*; D017539:Tunica Intima / Q000473:pathology; D014654:Vascular Patency
D009943:Organophosphorus Compounds; D011108:Polymers; D013193:Stainless Steel; C081660:poly(bis(trifluoroethoxy)phosphazene)