Screening for Sleep Hypoxemia in Pulmonary Arterial Hypertension (Sommeil_HTAP)

Pulmonary hypertension (PH) is a rare and severe disease of young adults, characterized by a progressive increase in pulmonary vascular resistances leading to cardiac failure and death. Patients with PH are categorized in two major groups: primary PH (PPH) wich is idiopathic, and secondary PH associated with many conditions such as chronic pulmonary embolic diseases (CPED).Increase in vascular resistance in PH is secondary to vasoconstriction and to a proliferative remodeling process of the arterial wall leading to obliteration of the small arterioles. On the other hand, hypoxemia is known to cause similar changes in vascular architecture. Also, some small cohorts study in the literature mentioned an increase of sleep hypoxemia prevalence accounting for almost 70% of cases. The mechanisms of this hypoxemia are completely unknown.Our study is observational, prospective and transversal, searching for hypoxemic respiratory sleep disorders (HRSD) in PPH and in CPEPH. Included patients will have one night polysomnography (CIDELEC) with a continuous measurement of transcutaneous PCO2.The major objectives are to determine the prevalence of HRSD, their physiopathologic mechanisms and their possible causal factors according to PH history, clinical findings and hemodynamic severity.