Effects of Normobaric Hypoxia During Exercise in Patients With Pulmonary Hypertension Receiving Sildenafil

Study Overview
=================
Brief Summary
-----------------
To study the effect of acute normobaric hypoxia during exercise in patients with pulmonary hypertension with/without Sildenafil

Official Title
-----------------
Hemodynamic Effects of Acute Normobaric Hypoxia During Exercise in Patients With Pulmonary Hypertension: Single-center Randomized Controlled Trial

Conditions
-----------------
Hypertension, Pulmonary

Intervention / Treatment
-----------------
* Other: Normobaric hypoxia (FiO2 15%) under Sildenafil
* Other: Normobaric hypoxia (FiO2 15%)


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Informed consent as documented by signature (Appendix Informed Consent Form) PH class I (PAH) or IV (CTEPH) diagnosed according to guidelines: mean pulmonary artery pressure >20 mmHg, pulmonary vascular resistance ≥3 wood units, pulmonary arterial wedge pressure ≤15 mmHg during baseline measures at the diagnostic right-heart catheterization Exclusion Criteria: resting partial pressure of oxygen <8 kilopascal at Zürich altitude on ambient air exposure to an altitude >1000 m for ≥3 nights during the last 2 weeks before the study inability to follow the procedures of the study patients who take nitrates other clinically significant concomitant end-stage disease (e.g., renal failure, hepatic dysfunction)

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Normobaric hypoxia (FiO2 15%) under Sildenafil<br>Inhalation of deoxygenated air through an altitude simulator (Altitrainer), for approx. 1/2 hour. given by a facemask, first at rest and then during exercise under Sildenafil. | Other: Normobaric hypoxia (FiO2 15%) under Sildenafil<br>* Inhalation of deoxygenated air through an altitude simulator (Altitrainer), for approx. 1/2 hour. given by a facemask, first at rest and then during exercise under Sildenafil.<br>|
| Experimental: Normobaric hypoxia (FiO2 15%)<br>Inhalation of deoxygenated air through an altitude simulator (Altitrainer), for approx. 1/2 hour given by a facemask, first at rest and then during exercise. | Other: Normobaric hypoxia (FiO2 15%)<br>* Inhalation of deoxygenated air through an altitude simulator (Altitrainer), for approx. 1/2 hour given by a facemask, first at rest and then during exercise.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| mean pulmonary artery pressure (mPAP) / cardiac output (CO) | Difference in mPAP/CO during exercise between tests under normoxia with/without Sildenafil | 4 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Differences in pulmonary arterial pressure | Differences in pulmonary arterial pressure at rest and during exercise with/without Sildenafil | 4 hours | 
| Differences in cardiac output | Differences in cardiac output at rest and during exercise with/without Sildenafil | 4 hours | 
| Differences in pulmonary vascular resistance | Differences in pulmonary vascular resistance at rest and during exercise with/without Sildenafil | 4 hours | 
| Differences in pulmonary artery wedge pressure | Differences in pulmonary artery wedge pressure at rest and during exercise with/without Sildenafil | 4 hours | 
| Differences in right atrial pressure | Differences in right atrial pressure at rest and during exercise with/without Sildenafil | 4 hours | 
| Differences in mixed venous oxygen saturation | Differences in mixed venous oxygen saturation at rest and during exercise with/without Sildenafil | 4 hours | 
| Differences in heart rate | Differences in heart rate at rest and during exercise with/without Sildenafil | 4 hours | 
| Differences in blood pressure | Differences in blood pressure at rest and during exercise with/without Sildenafil | 4 hours | 
| Differences in oxygen saturation | Differences in oxygen saturation at rest and during exercise with/without Sildenafil | 4 hours | 
| Differences in arterial blood gases | Differences in arterial blood gases at rest and during exercise with/without Sildenafil | 4 hours | 
| Differences in mixed venous blood gases | Differences in mixed venous blood gases at rest and during exercise with/without Sildenafil | 4 hours | 
| Differences in cerebral tissue oxygenation | Differences in cerebral tissue oxygenation at rest and during exercise with/without Sildenafil | 4 hours | 
| Differences in muscle tissue oxygenation | Differences in muscle tissue oxygenation at rest and during exercise with/without Sildenafil | 4 hours | 
| Differences in symptoms (Borg dyspnoea) | Differences in symptoms (Borg dyspnoea) at rest and during exercise with/without Sildenafil | 4 hours | 
| Differences in symptoms (Borg leg effort) | Differences in symptoms (Borg leg effort) at rest and during exercise with/without Sildenafil | 4 hours | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
hypoxia, exercise, blood markers