不同材料组配式带膜血管内支架的比较研究

Comparison of various configurations of dacron and politef-covered stents:application to modular endovascular systems

目的 通过比较涤纶 (D)、聚四氟乙烯 (PTFE)及可膨胀性聚四氟乙烯 (ePTFE)覆盖内支架不同组配的漏出量及结合点的阻力 ,确定带膜血管内支架的最佳材料。方法 研究分 5组 ,分别为涤纶组 1 (D1 )、PTFE组 1 (PTFE1 )、涤纶组 2 (D2 )、PTFE组 2 (PTFE2 )及可扩张PTFE组(ePTFE) ,每组含有 5个样本。每一样本由 1个PalmazP2 94内支架和内置、覆盖两段D、PTFE及ePTFE组成。各组以不同的方式进行组配。增加装配内压力 [1 0 0、2 0 0及 30 0mmHg(1mmHg=0 .1 33kPa) ]来验证其外漏 ,在装配两端安置拉力验证其结合点的阻力。方差分析 (ANOVA)用于组间比较。结果 在增加装配内压力时有 4个组配崩溃 (D1 3个 ,D2 1个 )。每 1 5s的漏出量在D1为 (38.4± 2 2 .3)ml,D2为 (40 .4± 1 0 .3)ml;PTFE1、PTFE2及ePTFE无漏出。在牵拉实验中各组在如下拉力下崩溃 ,D1 (4.86± 2 .66)N ,D2 (4.76± 2 .36)N ,PTFE1 (2 0 .49± 2 .80 )N ,PTFE2 (2 2 .0 3± 1 .88)N ,ePTFE (1 8.85± 2 .62 )N。结论 PTFE是带膜血管内支架的较理想材料 。

Objective To determine which graft material is the better choice for endovascular stent graft by comparing the leakage and resistance to traction of stents covered internally and externally with either Dacron (D),polytetrafluoroethylene (PTFE),or expanded PTFE (ePTFE).Methods Individual Palmaz P294 stents were assembled with collagen impregnated Dacron,PTFE or ePTFE covering the stent in one of 5 configurations (D1,D2,PTFE1,PTFE2,ePTFE).D1 and PTFE1 had a 7 mm diameter graft covering two thirds of the stent internally and another cover externally along the entire length of the stent.The same diameter grafts were used in D2 and PTFE2,in which the grafts covered the entire stent internally and externally;The ePTFE grafts were also totally covered the stent,but with 4 mm diameter graft that had been dilated to 8?mm.Resistance to leakage was tested by increasing the internal pressure (100,200 and 300?mm?Hg) with water injections;Traction was placed at both ends of the assembly to test resistance of the junction.Group comparisons were performed using ANOVA.Results Five samples of each configuration were tested.During the pressure test,4 samples collapsed (3 in D1 and 1 in D2).The amount of leakage per 15 s was (38.4±22.3)?ml for D1 and (40.4±10.3)?ml for D2 respectively;There was no leakage measured for PTFE1,PTFE2 and ePTFE.In the traction test,the samples collapsed under a force of (4.86±2.66) Newtons (N) in D1,(4.76±2.36)?N in D2,(20.49± 2.80)?N in PTFE1,(22.03±1.88)?N in PTFE2,(18.85±2.62)?N in ePTFE respectively.There was significant difference between Dacron and the PTFE groups in leakage and resistance.Conclusion PTFE stent PTFE configurations had no leakage under pressure and high resistance to traction as compared with stents covered with Dacron,suggesting that PTFE is a better material for an endovascular stent graft.ePTFE had the same characteristics as normal PTFE,but is easier to assemble in vivo.