| Purpose:To understand the gross anatomy,histopathological change and characteristics of the restenosis of the transjular intrahepatic portosystemic shunt(TIPSS).To determine the feasibility and effectiveness of the prevention and treatment of the restenosis of the TIPSS,we made control experiments by stents covered with small intestinal submucosa(SIS)(experimental group) and naked stents(control group).Material and methods:In our research 24 porcines were divided into two groups randomly:16 in experimental group,8 in control group.In the two groups the porcine TIPSS were established. Blood ammonia(BA) and serum total bilirubin(STB) was examined and portal vein pressure(PVP) was measured before and after operation.Shunt venography was performed at 2th, 4th week postoperatively.In autopsy we took out of the shunt and the hepatic tissue around it, then the shunt were separated into three portions:a part near to hepatic vein,parenchymal part and a part near to portal vein.We observed sample macroscopically and microscopically,and measured the thickness of the proliferative tissue of each portion.We made control research of the information and data between the two groups and processed the data statistically.Results:A technical success rate of 100%was obtained.According to the biochemistry examination,the BA and STB of the two groups 2w or 4w after operation was higher than before (P＜0.05),the difference between the two groups is not statistically significant(P＞0.05).The PVP of the two groups immediately after operation was higher than before(P＜0.05),the difference between the two groups is not statistically significant(P＞0.05).All the models underwent portal venography immediately after the operation,demonstrating patent shunt.But according to the portal venography 2,4 weeks after TIPSS,3/4,1/4 shunts were occluded in control group,1/8,6/8 shunts was occluded in experimental group,the rest of the shunts were restenosis in defferent degree,and the rates is statistically higher in control group than that in experimental group(P＜0.05).According to the microscopical observation,compare to the control group,the experimental group had lighter proliferation of granulation tissue,lighter thrombosis,lighter celluar inflammatory reaction,lighter proliferation of the new bile duct and lighter reaction of the hepatic tissue around the shunt.The expression of PCNA was higher inicontrol group than that in experimental group at 2th,4th week,but the difference is not statistically significant(P＞0.05).According to the scanning election microscope,the endothelium number per vision at 3000 power was significantly higher in experimental group than that in control group(P＜0.05).According to the transmission election microscope,the reaction of the hepatic tissue around the shunt in control group is severer than that in experimental group.Conclusion:①TIPSS could cut down the PVP efficiently,but have bad effect on the hepatic function.②The pseudo-intima proliferation in the shunt of TIPSS is the main cause of stenosis and occlusion in the intermediate and advanced stage.It can be located at any part of the shunt and most obvious at the parenchymal part.③The cellular inflammatory reaction and the defense reaction of the organism can occur at any time of the TIPSS.Thrombosis And the proliferation of the new bile are also the common pathological phenomena that accompany that.④Compared to the naked stent,the stent covered with SIS can prevent the proliferative fibrous tissue from growing into the shunt,lighten the thrombosis,lighten the cellular inflammatory reaction,lighten the proliferation of the new bile duct and the foreign body reaction,but can't improve the patency rate of the shunts efficiently.⑤Modifying the method of the TIPSS,improving the stent, and combining with the other ways for prevention of restenosis after TIPSS is still the focal point researched in future.
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