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 Th...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： 316L stainless steel BMS （316L-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. 〈br〉 Results Quantitative coronary angiography （QCA） showed similar luminal loss （LL） in the three groups：（0.21±0.17） mm for 316L-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. Conclusion The novel NF-BMS showed similar safety as 316L-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.展开更多
Magnesium alloy coronary stent becomes a hot research topic due to its biodegradable character for avoiding late thrombosis and late restenosis.However,fracture of Mg alloy stent was a common issue after implantation....Magnesium alloy coronary stent becomes a hot research topic due to its biodegradable character for avoiding late thrombosis and late restenosis.However,fracture of Mg alloy stent was a common issue after implantation.In this study,18 drug-eluting biodegradable AZ31 B stents were implanted into porcine coronary arteries to assess its structural integrity,corrosion behavior and microstructure change in vivo.The coronary artery tissue responses to AZ31 B stent implantation were detected by quantitative coronary angiography and optical coherence tomography at the set time periods.In addition,further analyses were focused on the stent structure integrity,corrosion behaviors and the microstructure change of Mg alloy stents after implantation.A large number of fractures on stent struts were observed by high-resolution transmission X-ray tomography clearly.Moreover,degradation products,twins and grain refinement that appeared in Mg alloy stent matrix after implantation were also observed during the study.Inferred from this study,it is shown that the loss of AZ31 B stent structural integrity may be the result of stress concentration,degradation and microstructure change.展开更多
文摘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： 316L stainless steel BMS （316L-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. 〈br〉 Results Quantitative coronary angiography （QCA） showed similar luminal loss （LL） in the three groups：（0.21±0.17） mm for 316L-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. Conclusion The novel NF-BMS showed similar safety as 316L-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.
基金financially supported by the National Key Research and Development Program of China(No.2016YFC1102404).
文摘Magnesium alloy coronary stent becomes a hot research topic due to its biodegradable character for avoiding late thrombosis and late restenosis.However,fracture of Mg alloy stent was a common issue after implantation.In this study,18 drug-eluting biodegradable AZ31 B stents were implanted into porcine coronary arteries to assess its structural integrity,corrosion behavior and microstructure change in vivo.The coronary artery tissue responses to AZ31 B stent implantation were detected by quantitative coronary angiography and optical coherence tomography at the set time periods.In addition,further analyses were focused on the stent structure integrity,corrosion behaviors and the microstructure change of Mg alloy stents after implantation.A large number of fractures on stent struts were observed by high-resolution transmission X-ray tomography clearly.Moreover,degradation products,twins and grain refinement that appeared in Mg alloy stent matrix after implantation were also observed during the study.Inferred from this study,it is shown that the loss of AZ31 B stent structural integrity may be the result of stress concentration,degradation and microstructure change.
