The REVEAL Registry™ is a multicenter, observational, U.S.-based study of the clinical course and disease management of pulmonary arterial hypertension (PAH) patients. All consecutive consenting patients diagnosed with WHO Group I PAH according to specific hemodynamic criteria at participating institutions will be enrolled. Participating patients will be followed for a minimum of five years from the time of enrollment.

Pulmonary arterial hypertension (PAH) is a chronic, progressive, and often fatal disease characterized by severe constriction of the blood vessels in the lungs. Over the past decade, significant strides have been made in the medical management and understanding of PAH. However, much remains to be learned about the clinical course of both idiopathic PAH and associated PAH, including clinical presentation, pace of progression, key parameters to monitor, impact of treatment, and prognosticators of outcome. As the unique body of knowledge generated by the REVEAL Registry grows, it is hoped that new understandings, insights, and treatments will emerge that will improve the lives of patients with PAH.

The REVEAL Registry will provide investigators with descriptive data regarding the clinical course and treatment outcomes in patients with WHO Group I PAH. Data derived from the study may offer important tools for assessing current management practices of treating investigators, as well as changes over time. Additionally, the relationship of patient- and disease-specific parameters to patient outcomes may be able to be assessed through analysis of data from this study.

The specific objectives of the REVEAL Registry™ are to:

• Characterize the demographics and clinical course of PAH patients
• Evaluate and compare patient outcomes
• Identify clinical predictors of short-term and long-term clinical outcomes
• Assess the relationship between PAH medications and patient outcomes
• Report temporal trends in treatments and outcomes for newly diagnosed patients
• Collect timely and relevant data for the evolving research needs of the PAH community

Inclusion Criteria:

• Newly diagnosed or previously diagnosed patients with WHO Group I PAH.
• Documentation of the following hemodynamic parameters by right heart catheterization, performed at any time prior to study enrollment:
• Mean pulmonary arterial pressure (mPAP) >25 mm Hg at rest or mPAP > 30 mm Hg with exercise contemporaneous with a pulmonary wedge pressure ≤ 18 mm Hg
• Pulmonary wedge pressure ≤ 18 mm Hg
• Pulmonary vascular resistance (PVR) ≥ 240 dynes.sec.cm-5 (i.e., ≥ 3.0 Wood units)

Exclusion Criteria:

• Patients who meet the criteria for inclusion into WHO Groups II, III, IV or V
• Have not had documentation of hemodynamic criteria for PAH by right heart catheterization at some time preceding study entry and following development of symptoms associated with PAH.
• Do not meet the required hemodynamic criteria for entry into the study

Patients with WHO Group I Pulmonary Arterial Hypertension from US based PAH centers.