Hemodynamic Effect of Nasal High-flow in Patients Suspected or Followed for a Precapillary Pulmonary Hypertension

Inclusion Criteria: \- patient addressed for right heart catheterization for pulmonary hypertension suspicion or follow-up. Exclusion Criteria: * necessity of FiO2 \>21% during right heart catheterization * intracardiac shunt * grade 4 tricuspid insufficiency * complete arrhythmia due to atrial fibrillation * Pregnant or breastfeeding women or women of childbearing age without an effective method of contraception * protected adult patient (tutorship or curatorship) * patient deprived of liberty by court or administrative decision * refusal of patient participation or consent * patient for whom the measurement of pulmonary arterial pressures during right heart catheterization is impossible * patient for whom, during the etiological assessment of pulmonary hypertension, the diagnosis of precapillary pulmonary hypertension cannot be confirmed and classified in groups 1, 3 or 4.