A third generation ultra-thin strut cobalt chromium stent: histopathological evaluation in porcine coronary arteries.
OBJECTIVE
The present study was designed to evaluate a novel third generation bare-metal stent (BMS) comprised of an ultra-thin-strut, cobalt-chromium platform with fixed geometry, uniform cell size, and superior surface finish in a porcine coronary artery model.


RESULTS
A total of 47 BMS of two types were implanted in pig coronary arteries using QCA to optimise stent apposition: a commercially available cobalt alloy thin-strut stent (91 microm) as control (Driver; n=17), and an ultra-thin-strut (65 microm) cobalt-chromium stent (Protea; n=18). Animals underwent angiographic restudy and termination one week and one month post-implant for coronary artery histology. In addition, 12 overlapping Protea stents were analysed at one month. At one week, comparable thin neointima and mild inflammation were observed in both groups. At one month, Protea demonstrated significantly lower angiographic % stenosis (2+/-1% vs. 17+/-5%, p=0.006), intimal thickness (0.11+/-0.01 mm vs. 0.23+/-0.03 mm, p=0.003), and histologic % area stenosis (19+/-2% vs. 32+/-3%, p=0.003). Mean stent strut injury scores were low and similar between groups. Angiographic % stenosis, intimal thickness, and histologic % area stenosis of overlapping Protea stents were 3+/-1%, 0.13+/-0.01 mm, and 22+/-2%, respectively, and similar to the single Protea group. Stable fibrocellular neointimal incorporation, with complete endothelialisation and minimal inflammation, were observed at one month in all stents, including overlapped Protea segments.


CONCLUSIONS
When compared to a commercially available cobalt alloy BMS, the new third generation Protea stent demonstrated favourable coronary arterial response with significant reduction of neointimal formation in the porcine model. Our results showed how seemingly trivial improvements to the BMS technology can result in substantial biological responses. Future, long-term investigations are needed to ascertain the clinical applicability and implications of these findings.
Jabara
Refat
R
Saint Joseph's Translational Research Institute, Saint Joseph's Hospital of Atlanta, GA, USA. Jabara@hadassah.org.il
Geva
Sarah
S
Ribeiro
Henrique B
HB
Chen
Jack P
JP
Hou
Dongming
D
Li
Jinsheng
J
King
Spencer B
SB
Chronos
Nicolas
N
Robinson
Keith A
KA
D015906:Angioplasty, Balloon, Coronary / Q000009:adverse effects / Q000295:instrumentation*; D000818:Animals; D002858:Chromium Alloys; D017023:Coronary Angiography; D023903:Coronary Restenosis / Q000209:etiology / Q000473:pathology / Q000517:prevention & control*; D003331:Coronary Vessels / Q000473:pathology*; D007249:Inflammation / Q000209:etiology / Q000473:pathology / Q000517:prevention & control; D008422:Materials Testing; D023421:Models, Animal; D011474:Prosthesis Design; D015607:Stents; D034421:Sus scrofa; D013997:Time Factors; D017539:Tunica Intima / Q000473:pathology
D002858:Chromium Alloys