Correlation of pressure gradient in three hepatic veins with portal pressure gradient

BACKGROUND The liver is one of the most important organs in the human body, with functions such as detoxification, digestion, and blood coagulation. In terms of vascular anatomy, the liver is divided into the left and the right liver by the main portal vein, and there are three hepatic efferent veins (right, middle, and left) and two portal branches. Patients with impaired liver function have increased intrahepatic vascular resistance and splanchnic vasodilation, which may lead to an increase in the portal pressure gradient (PPG) and cause portal hypertension (PHT). In order to measure the increased pressure gradient of portal vein, the hepatic venous pressure gradient (HVPG) can be measured to reflect it in clinical practice. The accuracy of PPG measurements is directly related to patient prognosis. AIM To analyze the correlation between HVPG of three hepatic veins and PPG in patients with PHT. METHODS From January 2017 to December 2019, 102 patients with PHT who met the inclusion criteria were evaluated during the transjugular intrahepatic portosystemic shunt procedure and analyzed. RESULTS The mean HVPG of the middle hepatic vein was 17.47 +/- 10.25 mmHg, and the mean HVPG of the right and left hepatic veins was 16.34 +/- 7.60 and 16.52 +/- 8.15 mmHg, respectively. The average PPG was 26.03 +/- 9.24 mmHg. The correlation coefficient and coefficient of determination of the right hepatic vein, middle hepatic vein, and left hepatic vein were 0.15 and 0.02 (P = 0.164); 0.25 and 0.05 (P = 0.013); and 0.14 and 0.02 (P = 0.013), respectively. The mean wedged hepatic vein/venous pressure (WHVP) of the middle and left hepatic veins was similar at 29.71 +/- 12.48 and 29.1 +/- 10.91 mmHg, respectively, and the mean WHVP of the right hepatic vein was slightly lower at 28.01 +/- 8.95 mmHg. The mean portal vein pressure was 34.11 +/- 8.56 mmHg. The correlation coefficient and coefficient of determination of the right hepatic vein, middle hepatic vein, and left hepatic vein were 0.26 and 0.07 (P = 0.009); 0.38 and 0.15 (P < 0.001); and 0.26 and 0.07 (P = 0.008), respectively. The average free hepatic venous pressure (FHVP) of the right hepatic vein was lowest at 11.67 +/- 5.34 mmHg, and the average FHVP of the middle and left hepatic veins was slightly higher at 12.19 +/- 4.88 and 11.67 +/- 5.34 mmHg, respectively. The average inferior vena cava pressure was 8.27 +/- 4.04 mmHg. The correlation coefficient and coefficient of determination of the right hepatic vein, middle hepatic vein, and left hepatic vein were 0.30 and 0.09 (P = 0.002); 0.18 and 0.03 (P = 0.078); and 0.16 and 0.03 (P = 0.111), respectively. CONCLUSION Measurement of the middle hepatic vein HVPG could better represent PPG. Considering the high success rate of clinical measurement of the right hepatic vein, it can be the second choice.