载药复合支架的抗血管组织增生的研究

在氧化钛表面改性的国产不锈钢支架上涂覆一定量药物,制备出新型复合的抗增生载药支架.观察支架植入猪冠状动脉3个月后血管的开通情况及血管的内膜反应.将7枚国产的普通不锈钢支架和7枚制备的新型载药支架植入14头小型猪冠状动脉内,3个月后对支架植入段血管进行血管造影、光镜及电镜检查并进行免疫组织化学分析.冠状动脉造影显示动物处死前支架段血管开通率100%,支架X光下清晰可见,未经特殊抗血栓治疗,支架段血管内无血栓形成.扫描电镜显示两组支架表面都完全被血管内膜覆盖,表面光滑,无血栓形成.覆盖的血管内膜中内皮细胞沿血流方向成典型的铺路石状排列.组织学形态分析显示植入支架3个月后,所有支架植入段血管内膜都有明显的增生,增生内膜主要由细胞外基质和平滑肌细胞构成.结论:含有新型载药支架的冠状动脉血管段内膜增生厚度比普通不锈钢支架的冠状动脉血管段内膜增生厚度小,这种载药复合支架具有良好的应用前景,需扩大样本进行深入研究.

Anti-restenosis Study on a New Drug Eluting Stent

The objective of this experimental study was to assess the effects of a new kind of drug eluting coronary stent. Fourteen mini-pigs were used; seven normal stainless stents and seven new drug eluting stents were implanted in their normal coronary arteries, respectively. Angiography was performed and followed by pressure-fixation of the coronary arteries for light and electron microscopic examinations at the end of three months after implantation. Repeated angiography showed that all the stented coronary segments were open. With no additional antithrombotic treatment, there was no thrombus formed in the stented coronary segments. Scanning electron microscopy analysis showed the implanted stent surface was covered by endomembrane without thrombus formation. The endothelial cell in the membrane was clear and lined by the direction of blood flow. Histomorphological analysis revealed the neointima in normal stainless stent group was thicker than that in new drug eluting stent group, and the neointima was composed of smooth muscle cell and extracellular matrix. The result of this study shows that this kind of stent could reduce the rate of the re-stenosis and occlusion of PTCA. This stent can be used in clinical trials.