Der TIPSS zur Therapie des portalen Hyperperfusionssyndrom. Erste Erfahrungen am Small-for-Size Mini-Pig-Modell

Abstract

Introduction: After extended liver resection or small-for-size liver transplantation with a remnant liver parenchyma of less than 0,5% of body weight often portal hyperperfusion has been noticed in the remaining liver. The influence of this portal hyperperfusion on the postoperative liver dysfunction has been discussed controversially. Several experimental and clinical studies tried to reduce the portal overflow. With the idea of an easily introducible and removable bypass we evaluated the Transjugular Intrahepatic Portosystemic Shunt (TIPSS) for temporary portal decompression in a small-for-size mini-pig model and report about our first experience with this new therapy combination. Material and methods: 20 mini-pigs between 24 and 40 kg underwent laparotomy under general anaesthesia. In all animals extended resection of the two left lobes and the right median lobe was performed using crash-clamp technique. Only the right lateral segments (RLS, approximately 25% of liver volume) left. After vena section of the V. jugularis interna the introduction of the TIPSS (Easy-Wall Stent, Titan, 6 mm diameter, 43 mm length) was performed under fluoros-copic control into the right lateral hepatic vein. TIPSS was placed into the main portal vein with finger guidance. Anticoagulation was initially done with 10000 iE Heparin i.V., followed by low molecular heparin subcutaneously once a day. Portal vein and TIPSS flow velocity was measured 1 hour and before scarification after 72 hours with 12 MHz Doppler-Duplex ultrasound. Results: The additional time for placing the TIPSS was 60 minutes in average. In 17 animals (85%) the TIPSS was successfully placed. In one case no hepatic vein was found for catheterisation (5%), two mini-pigs died due to technical reasons after extended hepatectomy (10%). In 8 of 17 pigs the TIPSS was open after 1 hour (47%). In 7 cases (41%) the TIPSS was occluded by thrombosis and 2 animals developed a pulmonary embolism within 1 hour after placement and died. 3 of 8 mini-pigs (37,5%) with open shunt after 1 hour died with signs of liver failure within 72 hours after resection. 62,5% (n = 5) of all mini-pigs with open TIPSS survived 72 hours but only in 3 of them (37,5%) TIPSS-flow was detected by ultrasound. Conclusion: The combination of small-for-size liver and TIPSS for partial portal decompression is technically feasible and easy. The high rate of post interventional thrombotic TIPSS occlusion (14/17, 82%) makes this technique not applicable in clinical settings. In this mini-pig model the high occlusion rate might be explainable with a race specific hypercoagulopathy.