Postprandial changes in portal haemodynamics in patients with cirrhosis.

Previous studies have shown that portal venous pressure increases in patients with cirrhosis after a protein meal. Since this increase may be mediated by an increase in hepatic blood flow or postsinusoidal hepatic vascular resistance, the present study was designed to examine the precise relation between the postprandial changes in these three variables in patients with cirrhosis and portal hypertension. Estimated hepatic blood flow (EHBF; indocyanine green clearance), portosystemic gradient (PSG; wedged free hepatic venous pressure), and postsinusoidal hepatic vascular resistance (PSR = PSG/EHBF) were measured simultaneously before and at 10 minute intervals after a high protein meal, containing 80 g protein, 40 g carbohydrate and 12 g fat (600 kcal) in nine patients (seven alcoholic, two non-alcoholic) with cirrhosis and portal hypertension. After the meal, the portosystemic gradient increased by 33% from mean (SEM) 15.6 (0.9) mm Hg to 20.7 (1.3) mm Hg, (p less than 0.01; Wilcoxon signed ranks test) within 30 minutes. Coincident with this increase in portosystemic gradient, estimated hepatic blood flow increased by 69.2% from 20.1 (1.7) ml/min/kg to 33.9 (2.5) ml/min/kg (p = 0.01), peak values occurring at 25 minutes, at which time the postsinusoidal hepatic vascular resistance had decreased by 31% from 1.10 (0.1) 10(-2) mm Hg/ml/min to 0.8 (0.5) 10(-2) mm Hg/ml/min (p = 0.01). These results suggest that the postprandial increase in portal venous pressure in patients with cirrhosis is mediated by an increase in hepatic blood flow and modified by a simultaneous decrease in postsinusoidal resistance.