Sildenafil and Pulmonary Artery Pressure

The purpose of the study is to see if the administration of sildenafil (Viagra) in patients with portopulmonary hypertension could be a safe and effective treatment. Portopulmonary hypertension (PTPH) is a special type of pulmonary hypertension. Pulmonary hypertension is high blood pressure in the pulmonary arteries that carry unoxygenated blood from the right ventricle of the heart to the lungs. Pulmonary hypertension results from constriction, or tightening, of the blood vessels that supply blood to the lungs. Consequently, it becomes difficult for blood to pass through the lungs, making it harder for the heart to pump blood forward. This stress on the heart leads to enlargement of the heart and eventually fluid can build up in the liver and tissues, such as in the legs. Affected patients can sometimes notice increasing shortness of breath and dizziness. There is a growing body of evidence suggesting a potential therapeutic role for this sildenafil in patients with primary pulmonary hypertension. Studies are ongoing regarding this area. Our hypothesis is that chronic oral sildenafil will successfully reduce pulmonary artery pressures by at least 25% (reduction in mean pulmonary artery pressure) and could be an effective treatment for PTPH, especially in candidates for liver transplantation Primary Hypothesis To measure the effects of a single dose of sildenafil on pulmonary arterial pressure in patients with PTPH Secondary Hypothesis To measure the effects of chronic (3 month) treatment with sildenafil on pulmonary arterial pressure, safety, and tolerability in patients with PTPH