Quantitation and fractionation of nutrient hepatic blood flow in normal persons, in persons with portal hypertensive cirrhosis, and after small-diameter portacaval H grafts.

Patients maintaining portal perfusion following small-diameter portacaval H grafts have better survival and lower portasystemic encephalopathy rates than those with reversed flow. To determine why this is so, we measured nutrient hepatic blood flow with the use of 99m-Tc-diisopropyl-IDA (DISIDA) clearance pharmacokinetics fractionated into its hepatic arterial and portal venous components. Patients with cirrhosis and portal hypertension had significantly lower nutrient hepatic blood flow than normal persons; this was due almost entirely to reduced portal flow. In patients with prograde portal flow after small-diameter H grafts nutrient hepatic blood flows were nominally reduced from levels seen in patients with portal hypertensive cirrhosis. Postoperative patients with reversed portal flow had significantly less nutrient hepatic blood than those with prograde flow. There was no evidence of significant hepatic arterial compensation for lost portal flow. Of four hemodynamic variables--portal flow direction, portal flow, arterial flow, and nutrient hepatic blood flow--only nutrient hepatic blood flow showed an independent correlation with clinical outcome. Portal perfusion is a critical factor in maintenance of adequate nutrient hepatic blood flow, primarily because hepatic arterial flow does not compensate chronically for lost portal perfusion.