Shunt operation

Demonstration of meat intoxication following an experimental shunt operation by J. Pawlov. 

Preoperative diagnosis prior to hepatic resection or shunt operation... 

In the light of a possible shunt operation, it has become more important to obtain additional information on the arterial blood supply to the liver. As regards cirrhosis with portal hypertension, arteriographic investigations have shown that the more the blood flow through the... 

In systemic diseases, splenectomy has to be considered. A shunt operation may be indicated in haemorrhage-free intervals. A proven alternative to the operative shunt is the transjugular intrahepatic portosystemic stent shunt. 

Liver transplantation not only removes the continued risk of variceal bleeding, but also eliminates the underlying liver disease causing portal hypertension. However, due to the scarcity of liver donors, limited financial resources and the life-long immunosuppression required, this major surgical intervention can only rarely be considered - perhaps in cases where a previous shunt operation or the creation of a TIPS was not possible. The survival rate for transplantation is higher than when recurrent bleeding is treated by repeated sclerotherapy (73% versus 17% after 4 years). The indication for transplantation (e. g. cirrhosis Child B or C) should be set as early as possible, (s. p. 872)... 

Patienten mit hepatischer Enzephalopathie nach portosystemischer Shunt-Operation. Z. Gastroenterol. (Suppl. 2) 1991 29 107-109... 

When considering the ideal time point for a shunt operation, a distinction is made between (1.) emergency shunt, (2.) early elective shunt, and (i.) elective shunt. 

Jacobs, D.L., Rikkers, L.F. Indications and results of shunt operations in the treatment of patients with recurrent variceal hemorrhage. Hepato-Gastroenterol. 1990 37 571-574... 

Previous shunt operations and TIPS need to be removed in order to guarantee that the transplanted liver is sufficiently supplied with portovenous blood. In these cases, the portal system is checked preoperatively for thromboses by means of colour-encoded duplex sonography and X-ray techniques. In any case, the confluence of superior mesenteric vein and splenic vein must be free. (391) The main advantage of portacaval end-to-side anastomosis is its low thrombosis rate of < 5% in addition, there is no need for a distal shunt ligature. In shunts distal to the hilus (mesocaval, distal splenorenal), no preparation of the liver hilus is required however, in 10% of cases, these shunts show portal vein thrombosis (in TIPS, up to 15%). Usually, all surgical shunts are disconnected or ligated before the liver transplantation is completed in order to... 

Plasma cholinesterase determinations have been helpful in assessing the suitability of a patient for shunt operations in portal hypertension or for liver transplantation (E18). Obstructive jaundice is not accompanied by a reduction of cholinesterase activity unless there is also damage to the hepatocytes. In cases of fatty liver, the plasma cholinesterase activity is generally normal or high. As indicated above, there is a positive correlation between the enzyme activity and plasma lipids or lipoproteins (CIO, C16, K36). 

H49. Hunt, A. H., and Lehmann, H., Serum albumin, pseudocholinesterase, and transminases in the assessment of liver function before and after venous shunt operations. Gut 1, 303-311 (1961). 

The extraction ratio for a particular dye tends to vary inversely with the plasma concentration (C9). There is also a tendency for the extraction ratio to vary inversely with the hepatic plasma flow. This has been reported after portacaval shunt operations in man (B43) and after hemorrhage or pyrogen administration in dogs (H7a). 

Most HE episodes in patients with chronic liver disease are precipitated by events such as oral protein load, gastrointestinal bleeding, obstipation, infection, especially peritonitis, hypokalemia and alkalosis complicating the use of diuretic drugs, administration of sedative drugs, for example for diagnostic procedures or induction of portal-systemic shunt via shunt operation or the TIPSS implantation. 

If NADPH is oxidized through the microsomal cytochrome system, then the pathway reducing NADP should be stimulated and the rate of glucose oxidation through the hexose monophosphate shunt should be accelerated in those tissues where the shunt operates. However, studies on the effect of thyroxine on glucose oxidation through the shunt pathways have yielded controversial results. 

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