High Altitude (HA) Residents With Pulmonary Vascular Diseases (PVD), 6 Minute Walk Distance (6MWD) Assessed at 2840m (HA) With and Without Supplemental Oxygen Therapy (SOT)

Effect of Supplemental Oxygen Therapy (SOT) in Patients With Pulmonary Vascular Diseases (PVD) Defined as Pulmonary Arterial Hypertension or Chronic Thromboembolic Pulmonary Hypertension (PH) Who Permanently Live >2500m on 6-minute Walk Distance (6MWD)

The investigators aim to study the effect of SOT in participants with pulmonary vascular diseases (PVD) defined as pulmonary arterial hypertension or chronic thromboembolic pulmonary hypertension (PH) who permanently live >2500m on 6-minute walk distance (6MWD) assessed at 2840m.

Participants with PVD diagnosed with precapillary PH with right heart catheterization and classified to groups 1 and 4 (PAH or CTEPH) who permanently live at HA >2500 (PVDHA) will have 6-minute walk distance near their living altitude in Quito at 2840m with and without SOT at 3l/min via nasal cannula according to a randomized cross-over design.

IInclusion Criteria:

• Adult patients 18-80 years old of both genders,
• Residence > 2500m of altitude
• diagnosed with precapillary PH (mean pulmonary artery pressure (mPAP) >20 mmHg, pulmonary artery wedge pressure (PAWP) ≤15 mmHg and pulmonary vascular resistance (PVR) ≥2 wood units (WU) by right heart catheterization) with PH being classified as PAH or CTEPH according to guidelines
• Patients stable on therapy
• New York Heart Association (NYHA) functional class I-III
• Provided written informed consent to participate in the study.

Exclusion Criteria:

• Age <18 years or >80 years
• unstable condition
• Patients who cannot follow the study investigations, patient permanently living < 2500m.
• Patients with moderate to severe concomitant lung disease (FEV1<70% or forced vital capacity <70%), severe parenchymal lung disease, severe smokers (>20 cigarettes/day)
• Severely hypoxemic patients at Quito permanently have persistent oxygen saturation by pulseoximetry (SpO2) <80% on ambient air.
• Patients with chronic mountain sickness (Hemoglobin > 19 g/dl in women, >21 g/dl in men)
• Patient with a non-corrected ventricular septum defect
• Relevant concomitant other disease of the heart, kidney, liver, blood (anemia hemoglobin<11 g/dl)