完全可降解聚乳酸西罗莫司洗脱支架在小型猪冠状动脉模型中的实验研究

Preliminary evaluation of fully bioabsorbable PLLA sirolimus eluting stents in a porcine model

目的评价新型全降解聚乳酸西罗莫司洗脱支架(XinsorbTM)在小型猪冠状动脉抑制新生内膜增殖的有效性和安全性。方法裸金属支架(Bare metal stent,BMS)16枚和Xinsorb支架16枚分别随机置入16头小型猪的前降支(16枚)和右冠状动脉(16枚)。置入30d和90d,复查冠状动脉造影后处死部分动物取出支架段血管,将支架分成等长的两部分,一半用树脂包埋后制作硬组织切片,苏木素和伊红染色(haematoxylin and eosin,HE)分析组织形态,评价新生内膜增殖及管腔狭窄率;另一半用戊二醛固定后用扫描电镜观察支架段血管内皮化情况。结果 Xinsorb支架置入后未出现支架内血栓,并有效防止血管弹性回缩造成的血管狭窄。病理分析提示:置入30d,Xinsorb支架比BMS能显著减少新生内膜面积(0.9±0.2)mm2比(2.2±0.2)mm2(P<0.05)和管腔狭窄面积(19.3±3.4)%比(38.2±5.3)%(P<0.05),置入30d时BMS内皮化完全,但Xinsorb支架表面有部分未完全内皮化,Xinsorb支架内皮化完全所需的时间在30～90d。结论 Xinsorb支架在置入小型猪冠状动脉90d内,可以有效地支撑血管壁防止弹性回缩并抑制新生内膜增殖,在置入早期轻度延迟内皮的修复。

Objective To evaluate the short and mid-term efficacy and safety of fully bioabsorbable polylactide sirolimus eluting stents （XinsorbTM） in inhibiting neointimal hyperplasia in a porcine coronary model. Methods Bare metal stents （BMS, n=16） and Xinsorb stents （n=16） were randomized and implanted in left anterior descending artery （n=16） and right coronary （n=16） of 16 swines.Following the coronary angiography, histomorphologic analysis was performed 30 days and 90 days after stents implantation, respectively.In detail,the stented arteries were cut into two pieces.The proximal pieces were fixed in 10% buffered formalin, embedded in metharylate for cross section preparation,stained with haematoxylin and eosin （H-E） for neointimal area and lumen area stenosis measure.The distal pieces were cut open lengthwise and fixed with 1% glutaraldehyde for endothelialization evaluation with scanning electron microscope（SEM）. Results By histomorphometric analysis, Xinsorb stents significantly reduced neointimal formation in comparison to BMS for 30 days in the porcine coronary models [neointimal area： 0.9±0.2 vs. 2.2±0.2 mm2;percentage of stenosis：（19.3±3.4）% vs. （38.2±5.3）%, P0.05].There was no significant difference in stenosis between BMS and Xinsorb stents after 90 days. The Xinsorb stents took about 1-3 months for the re-endothelialization process of the inner wall of the blood vessel, while the BMS took 30 days. Conclusions Xinsorb stents have succeeded in preventing elastic recoil and suppressing neointimal formation for the first 90 days, while only mildly delayed the endothelialization process of the stented blood vessel.