Hepatic microcirculation after continuous 7-day elevated intra-abdominal pressure in cirrhotic rats

It is well known that IAP elevation, even at the level of 10mmHg used for laparoscopic surgery leads to an increase in portal pressure and decrease in portal blood flow. Since hepatic hemodynamics are already disturbed in cirrhotics, we decided to investigate the possible role of chronically elevated intra-abdominal pressure thus simulating ascites under tension-in liver perfusion and function in cirrhotic portal hypertensive rats. Four groups of 10 rats each were studied, including two control and two CCl(4)(-) induced cirrhotic groups. These were subdivided into normal and increased IAP. Elevation and maintenance of increased IAP to 20mmHg for 7 consecutive days was achieved by means of an intraperitonially placed balloon filled with water. Liver microcirculation was assessed by means of laser-Doppler technique, while venous blood samples were obtained for determination of the biochemical parameters of liver function. Cirrhotic rats showed a significant decrease in liver microcirculation in relation to controls (15.7+/-2.5 versus 23.2+/-2.2, p=0.001). Elevation of IAP led to a significant decrease (p=0.001) of liver microcirculation in both groups, i.e. from 15.7+/-2.5 to 12.7+/-1.7 units of flow in cirrhotics and from 23.2+/-2.2 to 15.9+/-2.6 units of flow in control rats. Alkaline phosphatase, alanine aminotransferase and bilirubin concentrations were found increased in cirrhotics in comparison to controls (p=0.05). IAP elevation resulted in a further impairment of liver function, but the differences, were not statistically significant. In conclusion, chronically elevated IAP in cirrhotic rats is associated with a significant impairment of the already decreased hepatic blood flow due to liver cirrhosis. Thus, the possible consequences of decreased liver perfusion must be taken under consideration in any case of severe cirrhosis presented with ascites under tension.