Pulmonary Arterial Hypertension Quality Enhancement Research Initiative Extension Program

Inclusion Criteria: 1. Male and female adults (≥ 18 years of age) 2. Documented diagnosis of PAH (all of the following): i. RHC demonstrating mPAP \> 25 mm Hg and PCWP ≤ 15 and PVR \> 3 ii. FEV 1 \> 50% predicted normal iii. V/Q and/or CT scan excluding the thromboembolic etiology 3. Diagnosis of PAH \< 3 years 4. Need for PAH specific treatment 5. Desire to participate and signs an informed consent Exclusion Criteria: Any of the criteria below: 1. Poor mental function, drug or substance (e.g.,alcohol) abuse, or unstable psychiatric illness, which, in the opinion of the investigator, may interfere with optimal participation in the study 2. Prior participation in this program 3. Patients with pulmonary hypertension classified as group 2 - 5 Updated Clinical Classification of Pulmonary Hypertension (5th World Symposium on PH Modified Classification of PH)