覆膜支架TIPS分流道狭窄病理基础的实验研究

Stenosis of Transjugular Intrahepatic Portalsystemic Shunt (TIPS) with Covered Stent: Experimental Evaluation in Swine

目的 探讨覆膜支架防治TIPS分流道狭窄的有效性及病理学特征。方法 采用 11只家猪建立TIPS模型 ,7只植入国产覆聚胺酯膜Z型不锈钢支架 ,4只植入覆聚酯膜镍钛合金支架 ,术后 4、8、12周行门脉造影和组织病理学检查。结果 1例因术后死亡未行造影复查 (大体观察分流道仍通畅 )。术后 4周复查 4例 ,1例分流道通畅 ,形成纤维组织 ,表面覆盖扁平上皮细胞。 6例在术后 8、12周分流道内均无血流通过。其中 ,4例分流道两端有明显组织增生导致闭塞。 9例均伴有血栓形成。 4例支架伸入静脉内不足或嵌入肝实质内 ,1例于分流道门脉端可见胆汁染色。分流道三个部位的组织增生厚度对比 ,以门脉端最厚 (P <0 .0 5 )。结论 覆聚胺酯膜支架可有效防止增生组织向TIPS分流道的长入。带聚胺酯膜支架未能提高TIPS通畅率 ,血栓形成是其闭塞主要原因 ;纤维组织增生反应可导致分流道两端闭塞 ,以门脉端最明显。

Purpose To evaluate the effectiveness of covered stent implanted in TIPS and report the histopathologic characteristics occurred in stenotic TIPS. Methods TIPS models were established in eleven domestic swine,among them home made Z type stainless steel stent covered with urethane membrane and nitinol stent covered with polyester graft were implanted in seven and four swine respectively. Portal venography and autopsy were performed periodically after operation. Results Two of five swine which were followed up at the fourth week had a patent shunt with formation of fibrous tissues lined with a layer of smooth pseudoendothelium connecting with both the wall of inferior vena cava and one of portal vein. The other nine swine had occluded TIPS shunt at 8th and 12th week and were also accompanied with the thrombosis. Among the nine occluded shunts,there were four stents with insufficiently extended into the two veins or with trapped in hepatic parenchyma. In one of them there was bile staining at portal vein end. The thickness of proliferative tissue in the three portions of shunt was the thickest at the portal vein end. Conclusion Covered stent can prevent the proliferative tissue from growing into TIPS shunt.The stent covered with urethane membrane fail to improve the patency of TIPS shunt. Besides of the occlusion, fibrous tissue proliferation which is mainly located at both ends of the shunt can lead to stenosis or occlusion. [