Acute Exposure of High Altitude on Cardiac Output

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 High Altitude (Säntis; 2500m above sea level) on non-invasive cardiac output assessments by Finapres® NOVA Technology at rest and under exercise

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). During the exposure High Altitude (2500m) and Low Altitude (Zurich; 470m) up to 5 hours, the participants cardiac output non-invasively assessed will be measured repetitive during the whole intervention.

Official Title
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Acute Exposure of Simulated Hypoxia on Non-invasive Cardiac Output Assessments 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>The participants will be tested in Zurich (Low altitude: 470m above sea level) and consecutively at 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>The participants will be tested at High Altitude (Säntis; 2500m above sea level) and consecutively 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 |
| --- | --- | --- |
| Cardiac Output measured non-invasively | Change in non-invasive assessed cardiac output measured with a finger cuff (Finapres) during the exposure to High Altitude (2500m) compared to Low Altitude (Zurich; 470m) | Averaged over two minutes rest and 30 seconds end of exercise (exhaustion) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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High Altitude, non-invasive cardiac output, Finapres