外周动脉可吸收镁合金支架性能初探

Preliminary study of performance of peripheral absorbable magnesium alloy stent

目的初步探讨国产外周可吸收镁合金支架的安全性及有效性。方法电脑随机选取8只中国农业大学Ⅱ系小型猪，平均体质量（21．19±1．93）kg，将16枚可吸收镁合金支架分别置入实验动物双侧髂股动脉中，分别于置入后第30、45、60、75、90、105、120、135天电脑随机抽取1只动物复查并取出2枚支架。分析支架置入前后血液相关生化指标、影像表现及组织HE、弹性纤维染色的病理形态。支架置入前后各项指标对比采用配对t检验。结果支架置入前后白细胞及Mg、Na、K、Cl离子，转氨酶、腺苷脱氨酶、肌酐、尿素氮、肌酸激酶各指标差异无统计学意义（P〉0．05）。DSA造影显示，支架置入前髂股动脉直径（4．39±0．26）mm，置入后30～135d血管直径（3．85±0．71）mm（t=3．041，P=0．008），置入前后血管直径差值0～2．29mm，相差最小在第30天，最大在第90天；HE及弹性纤维染色提示支架置入后第60、90、120天血管出现明显狭窄。16枚支架，置入后30～135d的平均残余管腔直径（1．38±0．18）mm、管腔面积（1．51±0．41）mm^2、内弹力板围绕面积（1．91±0．22）mm^2、外弹力板围绕面积（4．79±0．79）mm^2、平均内膜厚度（0．11±0．06）mm、平均血管新生内膜面积（O．40±0．29）mm^2、面积狭窄百分比（21．96±16．48）％。支架在体内逐渐降解，至第135天时仍未完全降解，未出现塌陷、打折，支架内膜覆盖完全。结论该款外周可吸收镁合金支架在活体内应用安全、有效。

Objective To investigate the performance and safety of domestic peripherally absorbable magnesium alloy stent. Methods Sixteen absorbable magnesium alloy stents were implanted in the bilateral iliac-femoral arteries of 8 Chinese Agricultural University minipigs selected randomly with computer.The mean weight was （21.19±1.93）kg. One pig was randomly selected by computer on 30^th, 45^th, 60^th, 75^th, 90^th, 105^th, 120^th and 135^th days after stent implantation and both stents were removed. The biochemical, imaging and histopathology index of the pig before and after stent placement were analyzed, t test was used to compare data collected before and after stenting. Results The biochemical index changes showed no statistical significance after stent implantation, the DSA indicated that vessel diameter was （4.39±0.26） mm before stent implantation and （3.85±0.71）mm on the 30^th to 135^th day afterimplatation （t= 3.041, P= 0.008）, the balance of vessel diameter before and after stenting ranged from 0 to 2.29 mm, with minimun on 30^th day, and maximum on 90^th day; HE and verhoeffvangieson showed significant stenosis of the arteries occurred on 60^th, 90^th and 120^th day. From the 30^th day to 135^th day after stenting, the average diameter of residual lumen was （1.38±0.18） mm, the average area of residual lumen was （ 1.51±0.41 ）mm^2, the average area of internal elastic lamina was （1.91±0.22） mm^2, the average area of external elastic lamina was （4.79± 0.79） mm^2, the average thickness of endothelium was （0.11 ±0.06） mm, the average area of new intima was （0.40±0.29） mm^2, the average narrow area percentage was （21.96±16.48）%.The stent absorbed gradually, and not completely absorbed until 135^th day after stenting. Endometrial cells completely covered stent surface, and the stent did not break or collapse at all. Conclusions The peripherally absorbable magnesium alloy stents is safe and effective in animal experiment. Application of this stent in human should be investigated with further studies.