Fundamental study on safety of cavered retrieval ncetallic stent

覆膜可回收金属支架的实验研究目的：评价裸可回收金属支架（REMS）和覆膜可回收金属支架（REMS）在犬下腔静脉内的应用效果。材料如下：11只成年狗接受了裸露的REMS的放置，6只狗接受了用聚氨酯、涤纶和聚四氟乙烯覆盖的REMS。使用直径为0.35mm的圆形不锈钢、直径为0.2mm的不锈钢扭线和尼龙手术线。将不锈钢丝制成12个“之”字形发夹弯的圆柱体，其中一侧的6个弯被拧成小圆环。环由不锈钢线环绕。每两个相邻体的弯曲处用不锈钢螺纹连接。回收装置由带旋转手柄的不锈钢钩、长鞘管和Teflon杆组成。结果：放置1周后，裸露的REMS可从IVC中取出，但超过2周后，裸露的REMS和覆盖的REMS不能取出。血管造影显示所有REMS裸露组IVC管腔均通畅，REMS覆盖组IVC管腔均闭塞，病理检查显示REMS裸露组1周后IVC管腔内膜不完全覆盖，2周后IVC管腔内膜完全覆盖。在覆盖的REMS中，观察到红色血栓和不完全覆盖的内膜。尝试将涵盖的REMS用于闭塞性IVC病变是不可接受的。

Experimental Study on Covered Retrieval Expandable Metallic Stent.Summary : Purpose is to evaluate the efficasy of bared retrieval expandable metallic stent (REMS) and covered REMS in canine inferior vena cava. Meterials are as follows ; eleven adult dogs underwent the placement of bared REMS and six dogs underwent covered REMS with polyurethance, dacron and polytetrafuluoroethylene. Round stainless steel with diameter 0.35mm, twisted stainless steel thread with diameter 0.2mm and nylon surgical thread were used. The stainless steel wire was made into a cylindrical body with 12 zig zag hairpin bends, six bends of one side were twistcd to form small round loops. The loops were encircled by the stainless steel thread. Every two bends from neighboring bodies were connected by stainless steel thread. The retrieval set consists of a stainless steel hook with a rotating handle, long sheath and a Teflon rod. Results : After 1 week placemcnt, the bared REMS could be removed from IVC but over two weeks bared REMS and covered REMS could not be removed. Angiography showed the patency of the IVC lumen in all cases with bared REMS but occlusion in all cases with covered REMS.Pathological fidings showed incompletely covered intima on the surface of the bared REMS after 1 week placement and completely covered intima over 2 weeks. In covered REMS,the red thrombus and incompletely covered intima were noted. It is not acceptable for covered REMS to be tried to use for the obliterative IVC lesion.