FLT1 and Pulmonary arterial hypertension associated with portal hypertension: We did not observe a significant difference in circulating FLT1 levels between PoPH and non-PoPH cirrhosis groups in the second independent validation cohort, despite observing increased FLT1 immunohistochemistry staining in the PoPH liver peri-central region and elevated plasma FLT1 levels in PoPH subjects from the initial validation cohort.