BACKGROUND: Invasive right heart catheterization plays a central role in identifying pulmonary hypertension (PH) disorders. However, non-invasive biomarkers of portopulmonary hypertension (PoPH) are required. Liver stiffness evaluated by FibroScan® is useful for the assessment of liver fibrosis in patients with chronic liver diseases. This study sought to investigate the utility of liver stiffness for the classification of PoPH among precapillary PH patients. METHODS: A total of 46 patients [38 females, median (interquartile range) age 63.0 (50.8-72.0) years old] with precapillary PH were divided into a PoPH group (N = 6) and a non-PoPH group (N = 40) based on the presence of portosystemic shunts and/or portal hypertension with hepatic venous pressure gradient >
5 mmHg. RESULTS: The PoPH group showed higher cardiac index and lower pulmonary vascular resistance than the non-PoPH group. Other hemodynamic variables and liver fibrosis biomarkers such as fibrosis-4 index and albumin-bilirubin score were comparable between the 2 groups. Liver stiffness measurements in the PoPH group were significantly higher than those in the non-PoPH group [12.8 kPa (9.4-17.3 kPa) vs 4.15 kPa (3.30-5.50 kPa), p <
0.001]. The cut-off value for the classification of PoPH was 8.50 kPa from the receiver operating characteristic curve (area under curve 0.979, 95 % Confidence interval 8.50 kPa - 11.00 kPa). CONCLUSIONS: Liver stiffness evaluated by transient elastography may be a non-invasive biomarker to detect the liver status that caused PoPH among precapillary PH patients.