Pulmonary Hypertension (PH) is a severe disease with a bad prognosis. However, thanks to extensive research in this field, there are more and better treatment options that allow patients to participate in recreational activities at moderate altitude or bring up the question of air-travel.

Still very few is known about the effects hypoxic conditions have on PH patients. The aim of this study is to investigate the effects of hypoxia in comparison to normoxia and hyperoxia on pulmonary hemodynamics in patients with pulmonary hypertension during routine right heart catheterisation. We aim to get insight into the pathophysiology of pulmonary hemodynamics under hypoxic conditions in comparison to normoxia and hyperoxia in patients with pulmonary arterial and chronic thromboembolic pulmonary hypertension compared with control patients, that are scheduled for right heart catheterisation due to dyspnea but have no PH.

Inclusion Criteria:

• clinically indicated right heart catheterisation
• diagnosis of pulmonary arterial hypertension or chronic thromboembolic pulmonary hypertension or control without pulmonary hypertension

Exclusion Criteria:

• hemodynamically unstable
• partial pressure of Oxygen < 7.3kPa
• no informed consent
• pulmonary hypertension due to left heart disease, chronic lung disease or miscellaneous (Groups II, III and V) according to Galié ERJ 2015

Patients that come to our PH referral center for evaluation of PH and undergo a clinically indicated right heart catheterisation.