Free Hepatic Vein Pressure Is Not Useful to Calculate the Portal Pressure Gradient in Cirrhosis: A Morphologic and Hemodynamic Study.

PURPOSE: To systematically evaluate the accuracy of free hepatic vein pressure (FHVP), the internal reference for hepatic venous pressure gradient (HVPG). MATERIALS AND METHODS: Diameter and pressure measurements were obtained in multiple locations within the hepatic vein, inferior vena cava (IVC), and right atrium on 30 hepatic venograms in 29 consecutive candidates for transjugular intrahepatic portosystemic shunt creation. RESULTS: On angiography, 15 patients (52%) had hepatic veins showing a normal and conical appearance, whereas the other 14 had irregular or narrow (maximal diameter ≤ 6 mm) veins. Diameters of hepatic veins increased from 4.4 mm ± 0.9 (range, 3.3-7 mm) at a peripheral position to 8.7 mm ± 3.0 (range, 5.0-15.5 mm; P < .001) at a central position, and respective pressures decreased from 10.9 mm Hg ± 3.7 (range, 3-17 mm Hg) to 7.4 mm Hg ± 3.7 (range, 0-14 mm Hg; P < .001). Gradients between wedged hepatic vein pressure and central free hepatic vein, IVC, and right atrium pressures were 17.2 mm Hg ± 5.4 (range, 4-33 mm Hg), 18.0 mm Hg ± 5.8 (range, 4-33 mm Hg), and 20.0 mm Hg ± 5.9 (range, 4-33 mm Hg), respectively. Pearson correlation coefficients were 0.679 between the HVPG and hepatic atrial pressure gradient (HAPG) and 0.889 between the wedged hepatic vein/IVC pressure gradient (HCPG) and HAPG. CONCLUSIONS: FHVP measurement depends on catheter tip position and vein morphology. Its use to calculate HVPG is not recommended. The high agreement between the HCPG and the HAPG suggests that both gradients may be used if one considers a systemic difference of 2 mm Hg.