Experimental efficacy of an everolimus eluting cobalt chromium stent.
BACKGROUND
Rapamycin and its analogs are now being coated on different stent platforms, using different polymer matrices to prevent restenosis by impairing vascular smooth muscle cell proliferation and neointimal formation.


METHODS
We evaluated the feasibility and compared the efficacy of biostable polymeric everolimus and sirolimus (CYPHER, Cordis) eluting stents in a porcine coronary model. Cobalt chromium balloon expandable stents (ML VISION, Guidant) were coated with a polymer containing everolimus (190 mug/cm(2)). Twelve pigs underwent placement of 36 oversized sirolimus (n = 12), everolimus (n = 12), and bare metal (cobalt chromium, n = 12) stents in the coronary arteries.


RESULTS
At day 28, vessel injury scores were low (<0.25) and similar between each of the three test groups. The mean neointimal thickness was significantly lower in the everolimus- (0.13 +/- 0.07 mm, P = 0.02) and sirolimus-eluting stents (0.13 +/- 0.08 mm, P = 0.04) versus the bare metal stents (0.20 +/- 0.07 mm). The mean percent area stenosis was similar for the everolimus-eluting stents [(20.8 +/- 6.9)%] and the sirolimus-eluting stents [(20.8 +/- 7.6)%], and each was significantly less than that of bare metal stents [(26.1 +/- 7.8)%, P = 0.05].


CONCLUSIONS
Stent-based delivery of sirolimus and everolimus delivered via durable polymeric matrices are equally effective in the suppression of neointimal formation at day 28 in the porcine coronary model. Further study is necessary to document dose response and long-term comparative effects of these drug-eluting stents.
Carter
Andrew J
AJ
Medical Device Research Laboratory, Borgess Medical Center, Kalamazoo, MI 49048, USA. andrewcarter@borgess.com
Brodeur
Anastasia
A
Collingwood
Robin
R
Ross
Sarah
S
Gibson
Lori
L
Wang
Chi-An
CA
Haller
Scott
S
Coleman
Leslie
L
Virmani
Renu
R
D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects; D002858:Chromium Alloys; D017023:Coronary Angiography; D023903:Coronary Restenosis / Q000517:prevention & control; D003331:Coronary Vessels / Q000187:drug effects* / Q000473:pathology; D016503:Drug Delivery Systems; D000068338:Everolimus; D005240:Feasibility Studies; D007166:Immunosuppressive Agents / Q000494:pharmacology; D023421:Models, Animal; D011474:Prosthesis Design; D011897:Random Allocation; D012107:Research Design; D020123:Sirolimus / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D015607:Stents; D013552:Swine; D017539:Tunica Intima / Q000187:drug effects* / Q000473:pathology
D002858:Chromium Alloys; D007166:Immunosuppressive Agents; D000068338:Everolimus; D020123:Sirolimus