PORtopulmonary Hypertension Treatment wIth maCitentan - a randOmized Clinical Trial

Main Inclusion Criteria: * Male or female of at least 18 years of age * Confirmed diagnosis of portopulmonary hypertension Main Exclusion Criteria: * Severe hepatic impairment * Severe obstructive or restrictive lung disease * Pulmonary veno-occlusive disease * Systolic blood pressure (SBP) \< 90 mmHg at Screening * ALT/AST \>= 3 x ULN * Bilirubin \>= 3 mg/dL at Screening * Any known factor or disease that might interfere with treatment compliance, study conduct, or interpretation of results