Intimal proliferation and restenosis in paclitaxel-eluting stents with aminoparylene as carrier substance in swines.
BACKGROUND
Polymer as carrier substance for drugeluting stents (DES) has been accused of inducing inflammation and hypersensitivity reactions leading to restenosis and stent thrombosis. Thus, a new paclitaxel-eluting stent (PES) with aminoparylene as a carrier substance is tested in the present study.


METHODS
In 10 pigs, stents were implanted in the epicardial coronary arteries: 1) bare-metal stents (BMS, control stent); 2) cobalt-chromium stents (CCS); and 3) PES. Stent length was 15 mm, and diameter was 3 mm. The animals were restudied after 6 weeks. Quantitative coronary angiography was performed at baseline and follow up. Minimum luminal diameter (MLD) and late loss were calculated in all animals. Histologic vessel lumen, intimal proliferation and restenosis were determined by morphometry. Disruption of the lamina elastica interna (LEI) and inflammatory reactions were assessed by histology.


RESULTS
The MLD at baseline was 2.83 +/- 0.28 mm, and at follow up it was 2.29 +/- 0.44 (p < 0.05; n = 30). Late loss and angiographic restenosis were smallest in the CCS and largest in the PES (ns). Neointimal proliferation was similar for all 3 stents, ranging between 1.38 and 1.64 mm(2) (ns). There was a significant correlation between disruption of the LEI and inflammatory reactions.


CONCLUSIONS
PTs with aminoparylene as a carrier substance show similar late loss and angiographic restenosis to that of BM and CCS. The incidence of inflammatory reactions (35% of all histologic sections) is similar in all stents, but highest in PES. The mechanism of this reaction is unclear, but may be either due to the drug itself, the disruption of the LEI or to a hypersensitivity reaction.
Flueckiger
Annina
A
Swiss Cardiovascular Center, University Hospital, Bern, Switzerland.
Strahm
Yvonne
Y
Billinger
Michael
M
Meier
Pascal
P
Mettler
Daniel
D
Studer
Urs
U
Schaffner
Thomas
T
Hess
Otto M
OM
D000818:Animals; D049109:Cell Proliferation; D002858:Chromium Alloys; D017023:Coronary Angiography; D023903:Coronary Restenosis / Q000000981:diagnostic imaging / Q000209:etiology* / Q000473:pathology*; D023921:Coronary Stenosis / Q000628:therapy; D003331:Coronary Vessels / Q000473:pathology; D004195:Disease Models, Animal; D004342:Drug Hypersensitivity / Q000209:etiology; D054855:Drug-Eluting Stents / Q000009:adverse effects*; D015994:Incidence; D008670:Metals; D017239:Paclitaxel / Q000008:administration & dosage* / Q000009:adverse effects; D011108:Polymers / Q000009:adverse effects*; D015607:Stents / Q000009:adverse effects; D013552:Swine; D017539:Tunica Intima / Q000000981:diagnostic imaging / Q000187:drug effects / Q000473:pathology*; D014992:Xylenes / Q000009:adverse effects*
D002858:Chromium Alloys; D008670:Metals; D011108:Polymers; D014992:Xylenes; C011055:parylene; D017239:Paclitaxel