Observational Description of Compliance for the Daily Ventavis Use Via the Insight Program in Class III Pulmonary Arterial Hypertension Patients

Inclusion Criteria: * Male or female subjects aged ≥18 years * Newly Treated with Ventavis or treated with Ventavis for less than 6 months, with I Neb AAD device for the application, as described in the SmPC (Summary of Product Characteristics), complemented by the Insight * With Pulmonary Arterial Hypertension, Group I of the Dana point Pulmonary Hypertension Classification. * WHO (World Health Organization) /NYHA (New York Heart Association) Functional class III * Able and willing to give written informed consent for participation in the study Exclusion Criteria: Key contra indications: * Hypersensitivity to the active substance or to any of the excipients. * Conditions where the effects of Ventavis on platelets might increase the risk of haemorrhage (e.g. active peptic ulcers, trauma, intracranial haemorrhage). * Severe coronary heart disease or unstable angina; * Myocardial infarction within the last six months; * Decompensated cardiac failure if not under close medical supervision; * Severe arrhythmias; * Cerebrovascular events (e.g. transient ischaemic attack, stroke) within the last 3 months. * Pulmonary hypertension due to venous occlusive disease. * Congenital or acquired valvular defects with clinically relevant myocardial function disorders not related to pulmonary hypertension