Intrahepatic heterogeneity of hepatic venous pressure gradient in human cirrhosis

The hepatic venous pressure gradient (HVPG) is used to evaluate portal hypertension.

We measured HVPG in two separate liver veins in 169 liver vein catheterizations in 102 cirrhosis patients and in 27 patients with no liver disease (controls).

In the controls, the two measurements differed by 0.0 +/- 1.8 mmHg (mean +/- s, n = 27), upper 95% confidence limit 3.6 mmHg (mean + 2 s). HVPG ranged from -0.1 to 8.3 mmHg, upper 95% confidence limit 6.7 mmHg. In cirrhosis, the two measurements agreed within +/- 3.6 mmHg in 39%. In 61%, the measurements differed by 4-34 mmHg. In 35%, fluoroscopy demonstrated hepatic vein-to-hepatic-vein shunting in veins with low HVPG values. In some patients with HVPG measurements above 30 mmHg, Doppler ultrasound examination showed arterialization of the hepatic vasculature.

Our results demonstrate a hitherto unrecognized notable heterogeneity of the intrahepatic vasculature and HVPG measurements in cirrhosis. The presumption of interposition of non-flowing blood between the catheter tip and the portal system for the measurement of HVPG may thus be violated in about one-third of the cirrhosis cases because of abnormal outlet into hepatic venous shunts and in a minor fraction because of abnormal arterial inlet. In 26%, one measurement was below 12 mmHg, the other measurement above. If the HVPG had been measured in only one liver vein, 13% of the cases would have been classified in a lower risk group than appropriate according to the 12 mmHg concept of risk of bleeding from oesophageal varices.