Effects of portacaval shunting on hyperdynamic circulation in bile duct-ligated cirrhotic rats

Background/Aims: Liver cirrhosis and portal hypertension are associated with hyperdynamic circulation. Portacaval shunts are widely used to prevent recurrent hemorrhage, but the hemodynamic effects caused by these procedures have not been well characterized in cirrhosis. We therefore compared the hemodynamic effects of both end-to-side and side-to-side portacaval shunts in normal and cirrhotic rats. Methods: Sprague-Dawley rats were divided into six groups according to the operations they underwent. End-to-side or side-to-side portacaval shunts were performed in both rats with cirrhosis induced by bile duct ligation and sham-operated rats. Systemic and regional blood flows were measured by the radioactive microsphere method. Results: Portal pressures in the shunted rats decreased significantly. Cardiac index in cirrhotic rats (557+/-27 ml . min(-1). kg(-1)) was significantly higher than controls (455+/-21 ml . min(-1). kg(-1)), but the two types of shunts did not further increase cardiac index in either the cirrhotic or the sham-operated rats. After shunting, hepatic arterial flows approximately doubled. Portal tributary blood flows in the end-to-side shunted sham (108+/-13 ml . min(-1). kg(-1)) and cirrhotic (139+/-19 ml . min(-1). kg(-1) groups were significantly higher than their respective controls (62+/-8 and 76+/-5 ml . min(-1). kg(-1)). Portosystemic shunting indices were >99% in both the end-to-side and side-to-side shunted groups in cirrhotic and sham-operated rats. Conclusions: The hyperdynamic circulation in cirrhotic rats was not augmented by portacaval shunting operations (either end-to-side or side-to-side), despite essentially total portosystemic blood diversion. Compensatory increase in the hepatic arterial blood flow to the liver remained intact even in cirrhotic rats. A selective redistribution of cardiac output to the mesenteric vascular bed was observed after the shunting procedure. However, there were no significant differences in hemodynamics between the end-to-side and side-to-side shunted groups.