Maximal Exercise Capacity at 2500 m of High Altitude

Study Overview
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Brief Summary
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The impact of hypoxia on maximal work rate during incremental ramp exercise within 3-6 hours after arriving at 2500m of high altitude in patients with precapillary pulmonary hypertension

Official Title
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The Impact of Hypoxia on Patients With Precapillary Pulmonary Hypertension and Treatment of Adverse Effects

Conditions
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High Altitude Pulmonary Hypertension, Maximal Exercise Capacity

Intervention / Treatment
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* Procedure: Maximal Exercise Capacity


Participation Criteria
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Eligibility Criteria
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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 Zurich at 490 m low altitude 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 other clinically significant concomitant end-stage disease (e.g., renal failure, hepatic dysfunction)

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: Patients will be exposed to ambient air at 490m vs. hypoxic air at 2500m in a randomized sequence according to a cross-over design
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: High altitude 2500 m above sea level (high altitude)<br>Maximum Exercise Capacity in high altitude | Procedure: Maximal Exercise Capacity<br>* Maximal Exercise Capacity in incremental ramp exercise tests.<br>|
| Active Comparator: Low altitude 470 m above sea level (low altitude)<br>Maximum Exercise Capacity in low altitude | Procedure: Maximal Exercise Capacity<br>* Maximal Exercise Capacity in incremental ramp exercise tests.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Maximal work rate | Change in maximal work rate in Watt at 2500 vs. 490 m | 30 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Heart rate | Change in cardiorespiratory measurements: heart rate during a cycle incremental ramp exercise test at high altitude vs. low altitude | 30 hours | 
| Ventilation | Change in cardiorespiratory measurements: ventilation during a cycle incremental ramp exercise test at high altitude vs. low altitude | 30 hours | 
| Oxygen uptake | Change in cardiorespiratory measurements: Oxygen uptake, SpO2, blood gases during a cycle incremental ramp exercise test at high altitude vs. low altitude | 30 hours | 
| Arterial blood oxygenation saturation | Change in cardiorespiratory measurements: Oxygenation (SpO2) during a cycle incremental ramp exercise test at high altitude vs. low altitude | 30 hours | 
| Blood gases | Change in blood gases during a cycle incremental ramp exercise test at high altitude vs. low altitude | 30 hours | 
| Hemodynamics | Change in hemodynamics assessed by echocardiography | 30 hours | 
| Borg dyspnoea and leg fatigue scale | Change in post-exercise Borg dyspnoea and leg fatigue scale during a cycle incremental ramp exercise test at high altitude vs. low altitude | 30 hours | 
| Visual Analogue Scale for dyspnea | Change Visual Analogue Scale at high altitude vs. low altitude according to a 10cm scale from left to right, where the subject has to mark dyspnea with higher values in cm meaning worse dyspnea | 30 hours | 
| Electro cardiography | Prevalence of abnormal resting electro cardiography (ECG) at high altitude vs. low altitude | 30 hours | 
| Electro cardiography :ST-segment changes | Difference in ST-segment changes during cycle incremental ramp and constant work-rate exercise tests at high altitude vs. low altitude | 30 hours | 
| Electro cardiography: ST-segment changes under oxygen | 7Difference in ST-segment changes during cycle exercise tests without and with oxygen at high altitude | 30 hours | 
| Electro cardiography: Clinically relevant ischemia | Incidence of clinically relevant ischemia (>1mm ST-segment depression) during cycle exercise tests at high altitude vs. low altitude | 30 hour | 
| Electro cardiography: QT-Interval | Change of corrected QT-Interval, during cycle exercise tests at high vs. low altitude | 30 hours | 
| Electro cardiography: QT-Interval | Change of corrected QRS duration, during cycle exercise tests at high vs. low altitude | 30 hours | 
| Electro cardiography: PQ-Interval | Change of corrected PQ-Interval, during cycle exercise tests at high vs. low altitude | 30 hours | 
| Rate pressure product | Change of corrected Rate pressure product, during cycle exercise tests at high vs. low altitude | 30 hours | 
| Electro cardiography: Cardiac arrhythmia | Incidence of cardiac arrhythmia during cycle exercise tests at high altitude vs. low altitude | 30 hours |