Double Blind, Randomized Trial of Bosentan for Sarcoidosis Associated Pulmonary Hypertension

Inclusion Criteria: * Patients with known sarcoidosis 21. * Age 18 or greater * Patients with documented pulmonary hypertension with a PA mean \> 25 mm Hg as measured by cardiac catheterization within six months of entry into the study. Pulmonary artery occluding pressure and or left ventricular end diastolic pressure must be less than 15 mm Hg. * Patients with WHO class II or III * Six minute walk distance of between 100 to 500 meters * Patients on stable immunotherapy for their sarcoidosis, including prednisone, methotrexate, azathioprine, hydroxychloroquine, cyclophosphamide, thalidomide, and/or infliximab * Patients able to provide written consent Exclusion Criteria: * Patients on pulmonary vasodilator drugs (flolan, remodulin, bosentan, sildenafil) n the prior 28 days. Patients on stable dose of calcium channel blocker for more than 1 month prior to right heart catheterization can be continued on the calcium channel blocker. * Patients with severe airway obstruction as defined by FEV1/FVC of less than 35% * Patients with World Health Organization (WHO) class IV status. * Patients who are pregnant or breast feeding * Patients with significant left ventricular dysfunction with a left ventricular ejection fraction of less than 35% * Cardiac index \< 2.0 liters and/or right atrial pressure \>15 mm Hg * Significant liver dysfunction not due to sarcoidosis. * Patients with severe other organ disease felt by investigators to impact on survival during the course of the study. * Patients unable to perform the 6 minute walk study