Study Performed at Various Medical Centers to Learn More About Survival and Expected Course of Pulmonary Arterial Hypertension, a Type of High Blood Pressure in the Lungs Related to the Narrowing of the Small Blood Vessels in the Lungs

In this study researchers want to learn more about Pulmonary Arterial Hypertension, a type of high blood pressure in the lungs related to the narrowing of the small blood vessels in the lungs (group 1 according to WHO classification). Goal of the study is to describe the signs and risk factors of the illness at study start and the chances of survival.

The primary objective of the study is to describe baseline clinical characteristics and overall survival in a cohort of patients with pulmonary arterial hypertension (PAH) of WHO functional class I in Argentina.

Secondary objectives are to study the discriminatory ability of the risk assessment tool presented in the European Society of Cardiology and European Respiratory Society (ESC/ERS) 2015 guidelines and to explore the potential prognostic advantage of a low-risk profile at follow-up as treatment goal.

Eligibility Criteria:
Inclusion Criteria:

* Consecutive newly diagnosed patients by Right heart catheterization (RHC) from 01-Jan-2012 to 31-Dec-2017, belonging to one of the following of Group 1 PAH subgroups: Idiopathic (IPAH), or Heritable (HPAH), or Drug or toxin induced, or Associated (APAH) with one of the following: Connective tissue disease; Congenital heart disease with simple systemic to pulmonary shunt at least 1 year after surgical repair; Portal Hypertension or HIV infection.
* Diagnosis of PAH by RHC exhibiting a mean pulmonary artery pressure (MPAP) ≥ 25 mmHg and a pulmonary artery wedge pressure (PAWP) ≤15 mmHg at normal or reduced cardiac output, according to European Society of Cardiology and European Respiratory Society (ESC/ERS) 2009 guidelines or MPAP ≥ 25 mmHg and a PAWP ≤15 mmHg and a pulmonary vascular resistance (PVR) \> 3 WU according to ESC/ERS 2015 guidelines.
* Patients with at least one year documented follow up or that have died or received transplant before 1 year of follow up after baseline RHC and that have initiated treatment with a PAH-targeted medication.

Exclusion Criteria:

* Patients with severe concomitant left heart disease (left ventricular ejection fraction \<35%).
* Patients with restrictive lung disease (Forced vital capacity (FVC) \<60% predicted) other than connective tissue disease or obstructive lung disease (forced expiratory volume (FEV) \<60% predicted, with FEV1/FVC\<70%).
* Clinical or radiological evidence of Pulmo-Veno-Occlusive Disease (PVOD) or Pulmonary Capillary Haemangiomatosis (PCH).
* Hypertrophic obstructive cardiomyopathy.
* Severe proven or suspected coronary artery disease.
* Congenital or acquired valvular or myocardial disease if clinically significant apart from tricuspid valvular insufficiency due to pulmonary hypertension.
* Underlying medical disorders at baseline with an anticipated life expectancy below 2 years (e.g. active cancer disease with localized and/or metastasized tumor mass) or Clinical relevant hepatic dysfunction (Child-Pugh B and C) or Renal insufficiency (glomerular filtration rate \<30 mL/min).
* Diagnosis of a pulmonary hypertension from WHO groups 2, 3, 4 or 5.