PAH is a rare, and severe disease, potentially mortal, affecting preferentially young subjects. The knowledge and the international literature, as regards the quality of life, the expectations, the needs and the psychosocial characteristics of patients with PAH, are non-existent. But it is known that the persons affected by rare diseases are more vulnerable, on the psychological, social, economic and cultural planIn all the stages of the treatment, patients with PAH are confronted with heavy psychosocial situations, in a context of vital risk, with exceptional medicinal treatments (intravenous administration at home).