A novel high nitrogen nickel-free coronary stents system: evaluation in a porcine model.
OBJECTIVE
To study the safety of the novel high nitrogen nickel-free austenitic stainless steel bare metal stents (BMS) in a recognized porcine coronary model and to select a better grid structure of it.


METHODS
Three types of stents were randomly implanted in different coronary arteries of the same pig: 316 L stainless steel BMS (316 L-BMS) (n=12), novel high nitrogen nickel-free stents Grid A (NF-A-BMS) (n=12) and novel high nitrogen nickel-free stents Grid B (NF-B-BMS) (n=12). In total, eighteen animals underwent successful random placement of 36 oversized stents in the coronary arteries. Coronary angiography was performed after 36 d of stents implantation. Nine animals were respectively sacrificed after 14 d and 36 d for histomorphologic analysis.


RESULTS
Quantitative coronary angiography (QCA) showed similar luminal loss (LL) in the three groups: (0.21 ± 0.17) mm for 316 L-BMS, (0.16 ± 0.12) mm for NF-A-BMS, (0.24 ± 0.15) mm for NF-B-BMS (P>0.05). Histomorphomeric analysis after 15 d and 36 d revealed that there was also no significant difference among the three groups in neointimal area (NA) with similar injury scores respectively. High magnification histomorphologic examination showed similar inflammation scores in the three groups, but NF-A-BMS group had poorer endothelialization scores compared with NF-B-BMS group, 2.00 ± 0.63 vs. 2.83 ± 0.41 (P=0.015) at 15 d, which also could be proved by the scanning electron microscope. However, the difference could not been observed at 36 d.


CONCLUSIONS
The novel NF-BMS showed similar safety as 316 L-BMS during the short-term study. NF-B-BMS had better endothelialization than NF-A-BMS and this may owe to the specific strut units.
Department of Cardiology of Peking University First Hospital, Beijing 100034, China.
Bin
B
Zhang
Department of Cardiology of Peking University First Hospital, Beijing 100034, China.
Ming
M
Chen
Department of Cardiology of Peking University First Hospital, Beijing 100034, China.
Bo
B
Zheng
Department of Cardiology of Peking University First Hospital, Beijing 100034, China.
Xin Gang
XG
Wang
Department of Cardiology of Peking University First Hospital, Beijing 100034, China.
Xi Ting
XT
Wang
Department of Cardiology of Peking University First Hospital, Beijing 100034, China.
Yuan Yuan
YY
Fan
Department of Cardiology of Peking University First Hospital, Beijing 100034, China.
Yong
Y
Huo
D000818:Animals; D003331:Coronary Vessels; D009532:Nickel; D009584:Nitrogen; D011897:Random Allocation; D013193:Stainless Steel / Q000737:chemistry; D015607:Stents; D013552:Swine; D013556:Swine, Miniature
D013193:Stainless Steel; D009532:Nickel; D009584:Nitrogen
Austenitic steel; Bare metal stent; Endothelialization; Restenosis; Stent thrombosis