自体股静脉复合血管外支架修复股动脉缺损的组织学变化

Histologic changes in repair of arte ry defects by vein autograft with ext ravascular stent

目的探讨复合聚乙丙交酯(PGLA)血管外支架对自体静脉修复动脉缺损的组织学变化的影响。方法以30只犬两侧股动脉各切除5cm,用6cm同侧股静脉移植修复,随机一侧复合PGLA血管外支架为A组;另一侧仅行自体股静脉移植为B组。术后1、2、4、6、8周取材,HE、Masson和弹力染色,光镜观察组织形态变化,进行图像分析,PCNA免疫组化染色观察平滑肌细胞增殖。结果两组移植静脉内膜厚度和截面积都较正常静脉差异有极显著意义(P<0.01),且随时间的推移而递增;两组间内膜厚度、截面积差异有极显著意义(P<0.01)。两组中膜厚度和截面积较正常静脉差异有显著意义(P<0.05),两组管腔截面积与正常静脉相比差异有极显著意义(P<0.01);两组间比较自第4周起差异有极显著意义(P<0.01)。移植静脉PCNA阳性细胞较正常静脉明显增加,术后2周达到高峰,而后逐渐减少,B组PCNA阳性细胞数高于A组,其中在术后前6周两者差异有极显著意义(P<0.01)。实验中A组移植的静脉无明显炎症反应,PGLA血管外支架保持较完整的结构,强度没有明显改变。结论复合应用PGLA血管外支架移植静脉内膜增生和平滑肌增殖减少,管腔狭窄较少。

Objective To report the experimental observation on histologic changes of the arte rial defects repaired by femoral vein autograft with PGLA extravascular stent.Methods A 5cm segmental defect was made in the bilateral femoral arteries of 30dogs.The defects were repaired with ipsilateral segments of vein.Each animal was randomly operated on using a sheathed vein graft at one limb (group A)and an unsheathed one at the other(group B).The grafted veins were harvested at the 1st,2nd,4th,6th and 8th weeks after implantation.Then HE,Massons trichrome and elastica stainings we re done to microscopically observe the tissue morphological change,and to measur e the thickness and area of intima and media,as well as the diameter and area of the vessel.I mmunohistochemical stain with PCNA was done to investigate the proliferation of the smooth muscle cells.Results The intima and media of the grafted fe moral veins showed proliferation to different extents in any group and at any time.The differe nces in intimal thickness and area between the grafted and the normal vein s were sig-nificant (P<0.01)and increased as the time went on.The differences in intimal thickness an d area of the grafted femoral veins between groups A and B were also significant (P<0.01).The differences in medial thickness and area were significant between the grafted and the normal fe moral veins(P<0.01).The luminal area of the grafted femo ral veins gradually de-creased in groups A and B as the time we nt on but still showed a significant difference from that of the normal fem oral vein even at the 8th week(P<0.01).The difference of the luminal area o f the grafted femoral veins between g roups A and B became significant from the 4th week(P<0.01).PCNA-positive cells were rare in th e normal femoral veins but existed in the media and the intima of the grafted veins.T he number of PCNA positive cells increased in all groups as the time went on.It reached the peak at the 2nd week postoperativ ely and then decreased gradually,but was still higher than that in the normal vein even at the 8th week postoperatively,the di fference being significant (P<0.01).The number of PCNA positive cells in group A was smaller than that in group B.The difference in the number of PCNA positive cells was significant between group A and group B from the 1st week to the 6th week posto peratively(P<0.01).In the experiment,no obvious infla mmation was found in the vein grafts in group A,and,up to 8weeks after graft,the PGLA external ste nt still retained relatively intact structure without obvious change in its strength.Conclusion In the repair of an arterial defect wi th vein autograft,PGLA external ste nt can effectively reduce hyperplasia of t he intima and media and the stegnosis of lumen.[