可回收式锥形肝静脉支架的动物实验研究

Retrievable hepatic vein tapered-stent: an experimental study in pigs

目的通过动物实验评估可回收式锥形肝静脉支架的可行性、安全性及稳定性,探讨支架回收最佳时间。方法健康家猪24头,随机分为4组,每组6头。全身麻醉下经右颈内静脉入路接受肝中静脉可回收式锥形支架置入术,术后3、7、11、15 d分别接受支架回收。采用t检验对比各组支架置入后、回收前所测得的支架内血流压力变化差异。采集支架中段相邻血管组织标本作病理学检查,测量计算新生血管内膜厚度,单因素方差分析对比各组间新生内膜厚度差异。结果 24枚支架均成功置入,技术成功率100%;支架回收技术成功率为50%(12/24)。肝中静脉内压力测量显示,3 d组支架置入后与回收前比较,差异无统计学意义(P>0.05);7 d组、11 d组、15 d组支架置入后与回收前比较,差异有统计学意义(P<0.05)。各组间支架中段相邻组织新生内膜平均厚度两两比较,差异均有显著统计学意义(F=338.29,P<0.001)。结论可回收式锥形支架置入家猪肝静脉安全、可行,其最佳安全回收时间为3 d,最长不宜超过7 d。

Objective To evaluate the feasibility, safety and stability of implantation of retrievable tapered-stent in hepatic vein through experimental study in pigs, and to discuss the optimal time to retrieve the tapered-stent. Methods A total of 24 healthy pigs were randomly and equally divided in to 3 d group （n=6）, 7 d group （n=6）, 11 d group （n=6） and 15 d group （n=6）. Under general anesthesia, implantation of retrievable tapered-stent in the middle hepatic vein via the right internal jugular vein was performed in all the experimental pigs. The implanted tapered-stems of 3 d group, 7 d group, 11 d group and 15 d group were respectively retrieved at 3, 7, 11 and 15 days after the implantation. The mean in-stent blood pressure was determined before implantation and immediately before its retrieval, the changes in blood pressure were compared between the four groups by using t test. Specimens of vascular tissue adjacent to the middle section of the tapered-stent were collected and sent for pathological examination, the neo-intima thickness was measured, the differences in the neo-intima thickness between the four groups were analyzed by using single factor variance analysis. Results A total of 24 tapered- stents were successfully implanted, the technical success rate was 100%. The technical success rate of stent retrieval was 50% （12/24）. The measurements of blood pressure in the middle hepatic vein indicated that in the 3 d group the post-implantation pressure was not significantly different from the pre-retrieval pressure （P〉0.05） ; while in the 7 d group, 11 d group and 15 d group the post-implantation pressure was significantly different from the pre-retrieval pressure （P〈0.05）.Statistically significant differences in the mean neo-intima thickness of vascular tissue adjacent to the middle section of the tapered-stent existed between each other among the 7 d group, 11 d group and 15 d group （F= 338.29, P〈0.001）. Conclusion The implantation of retrievable tapered-stent in experimental pig＇s hepatic vein is safe and feasible, and the optimal time to retrieve the tapered-stent is 3 days, preferably not exceeding 7 days, after its implantation.