Group 1.4.3 Porto-pulmonary hypertension 
Porto-pulmonary hypertension (POPH) is defined by the development of PAH associated with increased pressure in the portal circulation [33,34]. Prospective hemodynamic studies have shown that 2-6% of patients with portal hypertension had PH [35,36]. However, RHC is mandatory for the diagnosis of portal PH, as several mechanisms may increase pulmonary artery pressure in the setting of advanced liver disease: hyperdynamic circulatory state with high cardiac output, fluid overload and diastolic dysfunction. Pulmonary vascular resistance (PVR) is usually normal in these cases.