Noninvasive test patterns across vascular and parenchymal liver diseases.

BACKGROUND AND AIMS: Vascular liver diseases such as porto-sinusoidal vascular disorder (PSVD), Budd-Chiari syndrome (BCS), and non-cirrhotic portal vein thrombosis (NCPVT) are rare causes of portal hypertension (PH) but share the same phenotype with parenchymal chronic liver disease (CLD). We assessed whether blood-based and elastography-based noninvasive tests (NITs) can: (i) differentiate vascular from parenchymal liver disease, (ii) detect specific signs of portal hypertension within etiologies and (iii) identify portal vein thrombosis. METHODS: Consecutive patients with PSVD, NCPVT, BCS, or CLD treated at a tertiary referral center between January 2022 and December 2024 were included. Assessed NITs included platelet count, liver stiffness measurement (LSM), spleen stiffness measurement (SSM), the SSM to LSM ratio, ANTICIPATE, and NICER. RESULTS: This study included 411 patients: PSVD n = 43, NCPVT n = 38, CLD n = 309, and BCS n = 21. Among patients without PVT, NIT patterns differed between etiologies. The PSVD showed low LSM despite elevated SSM, resulting in the highest SSM to LSM ratio. This ratio best discriminated PSVD from CLD and BCS (AUC ≥ 0.870); the proposed cut-off of > 2 showed good diagnostic performance. The ANTICIPATE also differentiated PSVD from CLD/BCS, whereas SSM alone did not. Detection of specific PH signs was etiology dependent. In PSVD, platelet count showed the highest accuracy (AUC 0.823). In CLD, several NITs were associated with specific PH signs but accuracy was limited. In BCS, differences of the tested NITs for specific PH signs were not statistically significant. Across etiologies, NITs showed limited accuracy for detecting PVT. CONCLUSION: Combined assessment of LSM and SSM, particularly the SSM to LSM ratio, supports differentiation of PSVD from parenchymal and posthepatic liver disease, whereas platelet counts was most informative to detect specific PH signs within PSVD.