Liver arterialization prevents thrombocytopenia after portacaval shunt in rats

Arterialization of the portal stump by right renal artery after portocaval shunt in the rat

Portosystemic shunts cause severe secondary effects, so that arterializations of the portal stump are planned to increase the blood supply to the liver. The aim of this study was to verify the technical feasibility of arterialization of the portal stump with the right renal artery in order to obtain a valid experimental model to study the pathophysiology of arterial revascularization of the liver. Twenty rats underwent end-to-side portocaval shunt + end-to-end anastomosis between the right renal artery and portal stump; another 20 rats were subjected to the same surgical procedure, but the portal stump underwent a reduction in size. In our study, both techniques gave good results, but the use of an operating microscope and good microsurgical training were essential in achieving a good patency rate (78.3%).

Regulation of hepatic thrombopoietin production by portal hemodynamics in liver cirrhosis

OBJECTIVE

This study was designed to clarify how thrombopoietin (TPO) functions in and, to some extent, causes thrombocytopenia complicating liver cirrhosis and portal hypertension.

METHODS

Our study population consisted of 19 cirrhotic and six noncirrhotic patients who underwent percutaneous transhepatic portography (PTP) and hepatic venography.

RESULTS

The platelet counts of the cirrhotic patients were significantly lower than those of the noncirrhotic patients (8.7 +/- 4.1 vs 17.4 +/- 7 x 10(4)/microl; p < 0.01). The flow direction in the splenic vein was confirmed by PTP. Ten hepatofugal and nine hepatopetal flow directions in the splenic vein were noted among the cirrhotics. The hepatofugal group showed lower portal venous pressure (20 +/- 10 vs 32 +/- 4 cm H2O; p < 0.01) than the hepatopetal group and had a higher incidence of hepatic encephalopathy (six of 10 vs zero of nine; p < 0.01). The hepatic vein-portal difference in TPO did not differ substantially between the cirrhotics and noncirrhotics (0.12 +/- 0.04 vs 0.24 +/- 0.07 fmol/ml). Comparisons of this value among the three groups showed the TPO difference to be lowest in the hepatofugal group (hepatofugal: 0.04 +/- 0.03, hepatopetal: 0.21 +/- 0.07, noncirrhotic: 0.24 +/- 0.07; p < 0.05).

CONCLUSIONS

Our findings suggest that TPO production in the cirrhotic liver is regulated by the portal blood supply to the liver. Thus, portal hemodynamics may play a critical role in the development of thrombocytopenia.

Course of thrombocytopenia of chronic liver disease after transjugular intrahepatic portosystemic shunts (TIPS). A retrospective analysis

Thrombocytopenia associated with chronic liver disease presents a difficult management issue. Most reports conclude that portocaval and distal splenorenal shunts do not improve platelet counts in this setting. The response of thrombocytopenia after transjugular intrahepatic portosystemic shunt placement has not been studied. All platelet counts of 21 patients undergoing intrahepatic shunt placement were determined retrospectively to accumulate values at one month prior to procedure, weekly for the first month after the procedure, and monthly thereafter to six months. Comparison of pre- and postshunt platelet means showed a significant increase in counts in patients with a postshunt portal pressure gradient < 12 mm Hg, with the increment evident by one week after the procedure. This response was not seen when preshunt thrombocytopenia was used as the lone variable. This study suggests that the transjugular intrahepatic portosystemic shunt may improve the thrombocytopenia associated with liver cirrhosis when these pressure gradients are attained.

Is thrombocytopenia in liver failure dependent on an inadequate synthesis of thrombopoietic stimulating factor by the liver?

Thrombocytopenia in liver diseases has been considered secondary to portal hypertension or to a consumption mechanism associated with fibrinolytic disorders. Several conflicting clinical reports and evidence from experimental models justify the above mentioned mechanisms only in part. We propose that thrombocytopenia may be consequent to an inadequate synthesis of a factor stimulating thrombopoiesis produced by the liver.