Acute Exposure to High Altitude on Exercise Capacity

Study Overview
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Brief Summary
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Randomized crossover Trial in patients with Pulmonary Hypertension (PAH, CTEPH) to assess the acute response to High Altitude (2500m above sea level) in constant loaded exercise capacity.

Detailed Description
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Low altitude baseline measurements will be performed in Zurich (460m asl) including Echocardiography, Right heart catheterization, 6MWT, pulmonary function test, clinical assessment and blood gas Analysis. Randomly assigned to the order of testing, the participants will be tested in Low Altitude (Zurich, 470m) and at High Altitude (2500m). Towards the end of the exposure after approximately 4 hours, the participants will perform a constant loaded exercise test on an Ergometer with a calculated resistance of their 60% max Workload. The patients will be encouraged to perform these tests up to their physical exhaustion.

Official Title
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Acute Exposure to Hypoxia in Precapillary Pulmonary Hypertension: Physiological and Clinical Effects at Rest and During Exercise

Conditions
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Pulmonary Hypertension

Intervention / Treatment
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* Other: Assessment at Low Altitude (470m above sea level)
* Other: Exposure to High Altitude (2500m above sea level)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Informed consent PH diagnosed according to internation Guidelines: mPAP ≥ 25 mmHg along with a PAWP ≤15 mmHg during right heart catheterization at the time of Initial diagnosis PH class 1 (PAH) or 4 (CTEPH) Stable condition, on the same medication for > 4 weeks Patient live permanently at an altitude < 1000m asl. Exclusion Criteria: Resting PaO2 ≤7.3 kPA corresponding to the requirement of long-term oxygen therapy > 16hour daily (nocturnal oxygen therapy alone is allowed) Severe daytime hypercapnia (pCO2 > 6.5 kPa) Susceptibility to high altitude related diseases (AMS, HAPE, etc.) based on previous experienced discomfort at altitudes. Exposure to an altitude >1500m for ≥3 nights during the last 4 weeks before the study participation Residence > 1000m above sea level Inability to follow the procedures of the study, e.g. due to language problems, psychological disorders, neurological or orthopedic problems with Walking disability Women who are pregnant or breast feeding

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: Including a baseline assessment and assessments at Low altitude and High altitude
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Order A<br>Firstly, the participants will have their assessments at low altitude (Low altitude: 470m above sea level) in Zurich and consecutively the exposure to High Altitude (Säntis; 2500m above sea Level). | Other: Assessment at Low Altitude (470m above sea level)<br>* Assessment at Low Altitude (in Zurich; 470m above sea level) in order to compare this data with High altitude exposure<br>Other: Exposure to High Altitude (2500m above sea level)<br>* Exposure to High Altitude (Säntis; 2500m above sea level) for approximately 5 hours<br>|
| Experimental: Order B<br>Firstly, the participants will exposed to High Altitude (Säntis; 2500m above sea level) and consecutively will they have assessement in Zurich (Low altitude; 470m above sea level). | Other: Assessment at Low Altitude (470m above sea level)<br>* Assessment at Low Altitude (in Zurich; 470m above sea level) in order to compare this data with High altitude exposure<br>Other: Exposure to High Altitude (2500m above sea level)<br>* Exposure to High Altitude (Säntis; 2500m above sea level) for approximately 5 hours<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| endurance time at High Altitude | The time of a constant loaded exercise test by an ergometer in sitting position at High Altitude will be compared with the same test at low altitude (370m above sea level) | 1 day at altitude | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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exercise capacity, High Altitude, contant loaded exercise test