Currently, the most commonly used parameter is the Hepatic Venous Pressure Gradient (HVPG), i.e., the difference between the wedged (WHVP) and the free hepatic venous pressures. HVPG represents the gradient between pressures in the portal vein and the intra-abdominal portion of inferior vena cava.

HVPG is a clinical measurement of the pressure gradient between the WHVP and the free hepatic venous pressures (FHPV), and thus is an estimate of the pressure gradient between the portal vein and the inferior vena cava.

Portal hypertension is defined as hepatic venous pressure gradient (HVPG) greater than 5 mmHg. HVPG is a surrogate for the portosystemic pressure gradient. Clinically significant portal hypertension is defined as a gradient greater than 10 mmHg and variceal bleeding may occur at a gradient greater than 12 mmHg.