Revatio Portal-Pulmonary Arterial Hypertension Trial

Inclusion Criteria: * Male and female patients with PPHTN. * A 6MWD test between 150 m and 450 m. * A pulmonary vascular resistance (PVR) \>250 dyn\*sec\*cm-5, a mean pulmonary artery pressure (PAPmean) ≥25 mmHg due to portal hypertension, and PCWP ≤ 15 mmHg. Right-heart catheterization results for the definite diagnosis of PH must follow the 2 - 6 week pre-treatment phase and not be older than 6 weeks at study start (will be considered as baseline values). * Portal hypertension defined either clinically or hemodynamically by the presence of cirrhosis (by ultrasound or biopsy) or portal vein thrombosis / obstruction (proven by portal vein Doppler) and any one of the following within one year of entry into the study: 1) Ascites (on ultrasound of the abdomen); 2) Splenomegaly (on ultrasound of the abdomen); 3) Esophageal or Gastric Varices (proven endoscopically); 4) Hepatic-venous pressure gradient (HVPG) \> 12 mmHg. * Treatment naive patients (with respect to PAH specific medication) and patients. Prior use of sildenafil for erectile dysfunction will be permitted. * 18 to 75 years of age at Visit 1. * Patients who are able to understand and follow instructions and who are able to participate in the study for the entire period. * Patients must have given their written informed consent to participate in the study after having received adequate previous information and prior to any study-specific procedures. Exclusion Criteria: * Participation in another clinical trial during the preceding 3 months. * Pregnant women or breast feeding women. * Patients with a medical disorder, condition, or history of such that would impair the patient's ability to participate or complete this study in the opinion of the investigator or the sponsor. * Patients with a history of severe allergies or multiple drug allergies. * Patients with hypersensitivity to the investigational drug or inactive constituents.