Pulmonary arterial hypertension (PAH) is a severe pulmonary vascular affection, which treatment has evolved in the last few years, improving quality of life. However, adherence to treatment has not been assessed in such patients. The investigators developed a collaborative care model involving clinical pharmacists in PAH. The objective of this work is to evaluate the impact of such model of care on medication errors and adverse events, quality of life and clinical criteria.

This randomized multicentre controlled study will include approximately 100 PAH patients (NYHA II to IV). After inclusion, patients will receive either collaborative care including consultations with specialized pharmacist and nurse, or classic follow-up. Each patient will be followed during 18 months from the date of inclusion.

The investigators hope to show the positive impact of a collaborative care model in PAH. More specifically, the investigators aim to show the interest of long-term patient education to improve patient safety related to drugs, but also their quality of life, and have preliminary data about usual clinical criteria.

Inclusion Criteria:

• Age over 18;
• Pulmonary arterial hypertension (NYHA II to IV);
• Any specific PAH treatment or oral anticoagulant.

Exclusion Criteria:

• Patients under 18 or protected by law;
• Patients who do not speak/understand French;
• Pregnancy;
• Patients enrolled in other clinical trials.