Sildenafil and Pulmonary Artery Pressure

This is a single center (only takes place at University of Chicago), open-label (doctor and subject know that the subject is taking the experimental drut), pilot study to evaluate the effects of sildenafil on pulmonary artery pressures in patients with portopulmonary hypertension. Patients who are diagnosed with PTPH after having routine care right heart catheterization will be asked if they are interested in participating. Approximately ten subjects will be enrolled. Subjects will undergo the following experimental procedures as part of their participation in this study: blood laboratory tests, medical history, physical exam, inhaled nitric oxide test, study drug (sildenafil) administration, and a pill count. Sildenafil will be given to these patients 3 times a day for a 12 week period to see if the study drug can lower their pulmonary artery pressures by at least 25%.