新型可降解聚合物血管支架的体内血栓形成评价

The in vivo thrombosis evaluation for the biodegradable polymer stent

新型可降解血管支架可降低异物留存体内的顾虑,因此广受重视且已有产品进入临床。但这些支架的可降解性质可能带来更多与血栓相关安全性的担忧。现有GB/T 16886.4标准明确其必须进行血栓相关评价,但未给出具体的评价方法。本研究以实验猪为模型,通过体内植入方式进行血栓评价,针对支架植入时、短期及长期植入后血栓形成等与已上市金属支架进行了比较性研究。其评价方法包括大体观察、数字血管造影术中分析、光学干涉成像技术分析、扫描电镜等。利用以上各种评价方法的优势,本研究实现了对此类血管内器械在考虑其降解过程中血栓形成的综合评价。结果说明,对可降解血管内植入器械的体内血栓形成评价,需考虑植入手术及术后与其体内变化过程相关的两个阶段,并充分利用各种评价手段的优势,并且适宜的已上市对照样品的选择也甚为重要。本研究力图通过实例提供新型可降解类血管支架可行的体内血栓评价方案,解决其临床前评价过程中的有关方法学问题,并为类似产品的评价方案设计提供参考。

New biodegradable intravascular stent can reduce risk of foreign bodies retained,thus,it is widely concerned and some of the products have been introduced into the clinic.However,the characteristic of biodegradable may lead to more safety concerns associated with thrombosis.To ensure the safety,the thrombus formation experiment in vivo needs to be carefully designed and evaluated based on GB/T 16886.4 standard,but current standard do not provide explicit testing and evaluating methods.Establishing animal model with experimental pigs,the study compares biodegradable coronary stents and metal stents by simulating clinical implantation in vivo on the thrombus formation in the implanting process,and after the short-term and long-term implantation.The evaluation methods include gross observation,digital subtraction angiography intraoperative analysis,optical coherence tomography analysis,scanning electron microscopy and so on.The results show that combining these methods could comprehensively evaluate the whole process of the thrombus formation from the beginning of implantation to the end of preclinical animal experiments,so that,it may better predict the clinical thrombosis risk,and the selection of the control was very important.The study tries to use the comparison examples of thrombosis on the new medical instrument to provide the clue for thrombosis evaluation in vivo on similar instruments and show the methodology on the preclinical evaluation.