Reduction in renal blood flow following acute increase in the portal pressure: evidence for the existence of a hepatorenal reflex in man?

BACKGROUND: To investigate the relation between changes in portal haemodynamics and renal blood flow (RBF) in patients with cirrhosis. PATIENTS/METHODS: Twenty patients with cirrhosis and transjugular intrahepatic portosystemic stent-shunts were divided into two groups which were well matched. At routine portography, either changes in unilateral RBF (group I) or changes in cardiac output (group II) before and after shunt occlusion were studied. Blood was obtained from the renal and systemic circulations for the measurement of neurohumoral factors before and after shunt occlusion in group I patients. RESULTS: After shunt occlusion, there was a progressive reduction in unilateral RBF from a mean (SD) of 289 (32) to 155 (25) (-43.5%) (p < 0.001). These changes correlated significantly with the changes in the portal atrial gradient (p < 0.001). There was no significant change in heart rate, mean arterial pressure and right atrial pressure. No significant changes were found in the concentrations of the various neurohumoral factors measured. There was a less notable but significant reduction in the cardiac output (-10.9%) (p = 0.02) unaccompanied by significant reduction in the pulmonary capillary wedge pressure or mean arterial pressure. CONCLUSIONS: These results suggest the existence of hepatorenal reflex in man which is important in the regulation of RBF, although other mechanisms may also be contributory.