两种设计不同的涂层支架的生物相容性研究

目的　评估两种不同结构设计的国产铂 -铱合金明胶蛋白涂层支架置入兔颈动脉后长期的生物相容性。方法　铂 -铱合金支架由 90 %铂和 10 %铱合金制成 ,一代支架为金属丝直径 0 13mm单丝缠绕的螺旋形结构 ,二代支架为金属丝直径为 0 175mm单丝缠绕的“之”字形结构。将两代支架浸入 10 %明胶溶液中经干燥后制成明胶蛋白涂层支架。将支架直视下置入 3 2只正常兔右颈动脉 ,术后 7、14、3 0、90d进行病理形态分析及电镜观察。　结果　 3 2只兔均成功置入支架 ,组织病理学检查显示 :术后 7d一代和二代支架组各有一例不完全性血栓形成。所有支架置入血管段均有不同程度新生内膜增生 ,偶见炎性细胞浸润。随观察时间延长 ,两组平均新生内膜厚度与新生内膜面积呈持续增加趋势 ,且二代明胶蛋白涂层支架组显著小于一代明胶蛋白涂层支架组 (P均 <0 0 0 0 1)。扫描电镜显示 :7d时二代涂层支架表面附着少量单层红细胞 ,几乎完全内皮化 ;14d时透射电镜观察显示血管平滑肌细胞呈典型的合成型改变。结论　不同金属丝直径、不同结构设计的两代国产铂 -铱合金明胶蛋白涂层支架置入兔颈动脉后均具有良好的生物相容性 ,且二代支架引起的新生内膜增殖反应较轻

The biocompatibility of different design of the gelatin coated Platinium-Iridium stents

Objectives To assess the biocompatibility of the two kinds of different design and wire diameter gelatin coated Platinium Iridium(Pt Ir) stents in rabbit carotid arteries. Methods Pt Ir coil stents made of either a 0.13 mm or 0.175 mm wire, which were mechanically twisted in a spiral shape or a zig zig shape, were randomly implanted in the right carotid arteries of 32 rabbits under vision. The gelatin coating of Pt Ir stent was made by immersing the stent in 10% gelatin solution and then air dried. The first group was the first generational gelatin coated Pt Ir stents ( n= 16); the second group was the second generational gelatin coated Pt Ir stents ( n= 16). 7 days?14 days?30 days?90 days following the stenting procedure, histopathology for evaluation thrombosis and inflammation, as well as morphometry for caculation of neointimal area and mean neointimal thickness were performed. Results 32 stents were successfully implanted into the right carotid arteries in 32 animals. 7 days after implantation, histopathologic examination revealed only one incomplete thrombosis both in 0.13 mm and 0.175 mm groups. There was rare inflammation. Scanning electron microscope showed minimal red cells deposition on the surface of stent and almost complete endothelialization developed. Morphometric analysis showed that neointimal area and mean neointimal thickness siginificantly increased continuously up to 12 weeks after stent implantation, wherase neointimal area and mean neointimal thickness were siginificantly smaller in the 0.175 mm second generational gelatin coated group compared to the 0.13 mm first generational gelatin coated group ( P < 0 000 1 , respectively). Conclusions Different design and wire diameter of the two generational gelatin coated Pt Ir stents have good biocompatibility. The second generational gelatin coated Pt Ir stent causes slighter proliferation response than the first generational gelatin coated Pt Ir stent.