Ambrisentan (Letairis) for Sarcoidosis Associated Pulmonary Hypertension

Inclusion Criteria: * Biopsy proven sarcoidosis * Mean pulmonary artery pressure \> 25 mmHg at rest and greater than 30 mmHg with exercise by right heart catheterization within 1 year prior to entry into study * Pulmonary capillary wedge pressure ≤ 15 mmHg * PVR values \>3.0 Woods units * Forced vital capacity (FVC) \>40% * WHO functional class II or III * Stable sarcoidosis treatment regimen for three months prior to entry into study * 6 minute walk distance between 150-450 meters * Stable dose of antihypertensive medications * On no other medication to treat PAH (sildenafil, tadalafil, vardenafil, treprostinil, epoprostenol, iloprost, bosentan, sitaxsentan) within one month prior to enrollment and during duration of the study * Non-pregnant females Exclusion Criteria: * Exercise limitation related to a non-cardiopulmonary reason (e.g. arthritis) * Severe systemic hypertension \> 170/95 * Patients with congestive heart failure (left ventricular dysfunction) or primary right ventricular dysfunction * Anticipation by the investigator for escalation in sarcoidosis treatment during the course of the study * Pulmonary hypertension related to etiology other than sarcoidosis (i.e. HIV, scleroderma, etc.) * Use within 1 month of an endothelin receptor antagonists (bosentan, sitaxsentan). * WHO functional class IV status * Patients with significant left ventricular dysfunction * 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.