经颈静脉肝内门体静脉内支架分流术术式改良的实验研究

目的：探讨建立改良式猪经颈静脉肝内门体静脉内支架分流术（TIPSS）模型的可行性及其意义。方法：11只家猪分成2组，7只采用改良术式（经肝段下腔静脉穿刺门脉）建立TIPSS模型，另4只行常规TIPSS作对照。共置入4枚进口覆膜镍钛合金支架，8枚国产覆聚氨酯膜支架。其中，改良组7只猪置入7枚支架（4枚进口支架，3枚国产支架）；对照组4只猪置入5枚国产覆膜支架（1只猪置入时支架发生移位，故加用1枚支架）。术后4周（5只），8周（2只）和12周（4只）进行门脉造影观察分流道通畅情况。动物处死后，行分流道大体和组织病理学检查。结果：术后4周，改良组2只分流道通畅（进口支架、国产支架各1枚），分流道表面均形成完整的假性内膜组织；另5只分流道在4至12周均闭塞，分流道内形成血栓，其中2只内支架伸入下腔静脉内不全，陷入肝实质内。常规组4只分流道在4、8和12周观察期内均闭塞。两组间分流道肝（下腔）静脉端，肝实质段和门静脉端各段的增生组织厚度对比差异均无显著性意义（t值分别为0．14、0．16和0．20，P值均＞0．05）。结论：改良式猪TIPSS模型的建立是安全和可行的。改良式TIPSS中应采用覆膜支架，并应有足够长度伸入至两端静脉内，有助于防止增生组织向分流道内长入。

Experimental study on the creation of modified TIPSS

Objective To evaluate the availability of modified transjugular intrahepatic porto systemic stent shunt (TIPSS) established in porcine model. Methods Modified TIPSS was established in seven swine by direct puncture from hepatic IVC to portal vein while routine TIPSS was performed in four swine. The implanted stents included home made stainless steel Z stent covered with urethane membrane ( n =8) and nitinol stent covered with polyester graft ( n =4). Portal venography and histopathologic examination were performed periodically at 4th, 8th, and 12th week after operation. Results In modified TIPSS group, two swine (one with nitinol stent and another with stainless steel Z stent) had patent shunt lined with a layer of smooth and complete pseudo intimal tissue. The other five swine followed up during 4th, 8th, and 12th week were demonstrated thrombosis in occluded TIPSS. Insufficient stent extention into IVC and stent impeding into hepatic parenchyma occurred in two swine. Four shunts in routine TIPSS group were occluded during observation period. Comparing of thickness of hyperplastic tissue at each section of shunt, there was no significant difference between the two groups ( t =0.14, 0.16, and 0.20, respectively, P >0.05). Conclusion Establishment of modified TIPSS model in swine is safe and available. The usage of covered stent in modified TIPSS is recommended. Covered stent with a sufficient extention into two venous systems is helpful for the formation of pseudo intimal and is also helpful for the prevention of ingrowing hyperplastic tissue.