Meal induced changes in hepatic and splanchnic circulation: a noninvasive Doppler study in normal humans.

The haemodynamic effects of a meal on the splanchnic and hepatic circulation were evaluated in 30 healthy volunteers, using Doppler ultrasonography. The resistance index (RI) of the superior mesenteric artery and of the left and right intrahepatic arteries, the portal vein blood flow as well as the ratio between maximal velocity in the left and right intrahepatic arteries and the adjacent portal vein were measured initially, then 15, 30, 45, and 60 min after the ingestion of a standard balanced liquid meal. Postprandial haemodynamic changes were maximal 30 min after the meal; at that time, mesenteric artery RI decreased significantly [mean -11% (SEM 14%)] whereas portal vein blood flow increased markedly [mean +79% (SEM 14%)]; a significant increase in hepatic artery RI was observed in both liver lobes. The ratio between maximal velocities of the intrahepatic artery and the intrahepatic portal vein was reduced significantly; this ratio decreased more markedly in the right lobe of the liver. These findings would suggest that there was an adaptation of hepatic artery to portal vein blood flow after a meal. The subsequent increase in intrahepatic portal vein flow velocity was found to be greater in the right lobe of the liver.