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NCT Number: NCT07804576

Assessment of Lung Function (Lufu) at Sea Level LA vs. High Altitude HA in Patients With Pulmonary Arterial Hypertension PAH

To study the effect of a re-ascent to high altitude (Quito Ecuador: 2850m) after a one-week stay at sea level (after prior descent from 2850m) on lung function and pulmonary resistance/reactance in patients with pulmonary arterial disease PAH, who live permanently > 2600m.

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Key information

Conditions

Pulmonary Arterial Hypertension (PAH) Altitude Sickness High Altitude High Altitude Effects Hypertension, Pulmonary Lung Diseases Lung Function Changes Lung Function Testing Pulmonary Arterial Hypertension Pulmonary Vascular Disease Respiration Disorders Respiratory Tract Diseases

Age range

18 year–80 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University Hospital of Zurich

Zurich, 8091, Switzerland

About this study

The aim of this research is to investigate the lung function and pulmonary resistance/reactance before and after re-ascent (sea level for 7 days after prior descent from 2850m vs. re-ascent to 2850m) in patients with diagnosed pulmonary hypertension according to guidelines, who permanently live at high altitude over 2600m.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Adult patients aged 18-80 years and of all genders
  • Permanent residence > 2600 m
  • Diagnosis of pulmonary arterial hypertension PAH (PAHHA-Group) according to guidelines
  • Patients are stable on therapy
  • NYHA (new york heart association) functional class I-III.
  • 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 < 2600m.
  • Patients who traveled and stayed overnight at altitudes <2000 m in the past 4 weeks.
  • 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 having persistent SpO2 (oxygen saturation by pulseoximetry) <80% on ambient air.
  • Patient with a non-corrected ventricular septum defect
  • Relevant concomitant other disease of the heart, kidney, liver, blood (anemia hemoglobin<11 g/dl)

Treatment and study plan

Re-ascent from sea level to 2850m

Behavioral

Descent from 2850m to sea level with a stay for 7 days and re-ascent/return back to their usual living altitude at 2850m

Primary outcomes

  1. FEV1 after re-ascent to 2850m

    Time frame: From Day 4 at sea level to the day after re-ascent (Day 9: approximately 6 days)

    Difference/change in forced expiratory volume in one second FEV1 between sea level (measurement on the 4th day) and day after re-ascent to 2850m in patients with pulmonary arterial hypertension

Secondary outcomes

  1. Forced Vital Capacity FVC after re-ascent to 2850m

    Time frame: From Day 4 at sea level to the day after re-ascent (Day 9: approximately 6 days)

    Difference/change in forced vital capacity FVC between sea level (measurement on the 4th day) and day after re-ascent to 2850m in patients with pulmonary arterial hypertension

  2. FEV1/FVC after re-ascent to 2850m

    Time frame: From Day 4 at sea level to the day after re-ascent (Day 9: approximately 6 days)

    Difference/change in FEV1/FVC between sea level (measurement on the 4th day) and day after re-ascent to 2850m in patients with pulmonary arterial hypertension

  3. Respiratory Impedance (forced oscillation technique) after re-ascent to 2850m

    Time frame: From Day 4 at sea level to the day after re-ascent (Day 9: approximately 6 days)

    Difference/change in respiratory impedance (forced oscillation technique) between sea level (measurement on the 4th day) and day after re-ascent to 2850m in patients with pulmonary arterial hypertension

  4. Respiratory resistance (forced oscillation technique) after re-ascent to 2850m

    Time frame: From Day 4 at sea level to the day after re-ascent (Day 9: approximately 6 days)

    Difference/change in respiratory resistance (forced oscillation technique) between sea level (measurement on the 4th day) and day after re-ascent to 2850m in patients with pulmonary arterial hypertension

  5. Respiratory reactance (forced oscillation technique) after re-ascent to 2850m

    Time frame: From Day 4 at sea level to the day after re-ascent (Day 9: approximately 6 days)

    Difference/change in respiratory reactance (forced oscillation technique) between sea level (measurement on the 4th day) and day after re-ascent to 2850m in patients with pulmonary arterial hypertension

  6. FEV1 after 4 days at sea level

    Time frame: From high altitude (Day 0, 2850m) to day 4 at sea level (approximately 5 days)

    Difference/change in FEV1 between 2850m (prior to descent) and day 4 at sea level in patients with pulmonary arterial disease

  7. Forced Vital Capacity FVC after 4 days at sea level

    Time frame: From high altitude (Day 0, 2850m) to day 4 at sea level (approximately 5 days)

    Difference/change in forced vital capacity FVC between 2850m (prior to descent) and day 4 at sea level in patients with pulmonary arterial disease

  8. FEV1/FVC after 4 days at sea level

    Time frame: From high altitude (Day 0, 2850m) to day 4 at sea level (approximately 5 days)

    Difference/change in FEV1/FVC between 2850m (prior to descent) and day 4 at sea level in patients with pulmonary arterial disease

  9. Respiratory Impedance (forced oscillation technique) after 4 days at sea level

    Time frame: From high altitude (Day 0, 2850m) to day 4 at sea level (approximately 5 days)

    Difference/change in respiratory impedance (forced oscillation technique) between 2850m (prior to descent) and day 4 at sea level in patients with pulmonary arterial disease

  10. Respiratory resistance (forced oscillation technique) after 4 days at sea level

    Time frame: From high altitude (Day 0, 2850m) to day 4 at sea level (approximately 5 days)

    Difference/change in respiratory resistance (forced oscillation technique) between 2850m (prior to descent) and day 4 at sea level in patients with pulmonary arterial disease

  11. Respiratory reactance (forced oscillation technique) after 4 days at sea level

    Time frame: From high altitude (Day 0, 2850m) to day 4 at sea level (approximately 5 days)

    Difference/change in respiratory reactance (forced oscillation technique) between 2850m (prior to descent) and day 4 at sea level in patients with pulmonary arterial disease

  12. FEV1 pre-descent and after re-ascent (2850m)

    Time frame: Baseline at 2850m followed by a one-week stay at sea level to the day after re-ascent back to 2850m (time frame approximately 11 days)

    Difference/change in FEV1 at 2850m with a one-week stay at sea level in between (day pre-descent vs. day after re-ascent) in patients with pulmonary arterial disease

  13. Forced Vital Capacity FVC pre-descent and after re-ascent (2850m)

    Time frame: Baseline at 2850m followed by a one-week stay at sea level to the day after re-ascent back to 2850m (time frame approximately 11 days)

    Difference/change in forced vital capacity FVC at 2850m with a one-week stay at sea level in between (day pre-descent vs. day after re-ascent) in patients with pulmonary arterial hypertension

  14. FEV1/FVC pre-descent and after re-ascent (2850m)

    Time frame: Baseline at 2850m followed by a one-week stay at sea level to the day after re-ascent back to 2850m (time frame approximately 11 days)

    Difference/change in FEV1/FVC at 2850m with a one-week stay at sea level in between (day pre-descent vs. day after re-ascent) in patients with pulmonary arterial hypertension

  15. Respiratory Impedance (forced oscillation technique) pre-descent and after re-ascent (2850m)

    Time frame: Baseline at 2850m followed by a one-week stay at sea level to the day after re-ascent back to 2850m (time frame approximately 11 days)

    Difference/change in respiratory impedance (forced oscillation technique) at 2850m with a one-week stay at sea level in between (day pre-descent vs. day after re-ascent) in patients with pulmonary arterial hypertension

  16. Respiratory resistance (forced oscillation technique) pre-descent and after re-ascent (2850m)

    Time frame: Baseline at 2850m followed by a one-week stay at sea level to the day after re-ascent back to 2850m (time frame approximately 11 days)

    Difference/change in respiratory resistance (forced oscillation technique) at 2850m with a one-week stay at sea level in between (day pre-descent vs. day after re-ascent) in patients with pulmonary arterial hypertension

  17. Respiratory reactance (forced oscillation technique) pre-descent and after re-ascent (2850m)

    Time frame: Baseline at 2850m followed by a one-week stay at sea level to the day after re-ascent back to 2850m (time frame approximately 11 days)

    Difference/change in respiratory reactance (forced oscillation technique) at 2850m with a one-week stay at sea level in between (day pre-descent vs. day after re-ascent) in patients with pulmonary arterial hypertension

Study contacts

Contact information is provided by the study sponsor or research team.

Michael Furian, Prof. Dr. sc. ETH

CONTACT

+41442552220

Silvia Ulrich, Prof. Dr. med.

CONTACT

[email protected]

+41442552220

Sponsors and collaborators

Lead sponsor

Silvia Ulrich Somaini

Other

Registry information

Official study title

Effect of a One-week Descent From 2850m to Sea Level and Re-ascent in Patients With Pulmonary Arterial Hypertension and Healthy Controls Permanently Living > 2600m on Pulmonary Hemodynamics, Exercise Capacity, Blood Oxygenation, Sleep Disordered Breathing and Further Outcomes

Important dates

Study start
2026
Primary completion
2026
Study completion
2026
First posted
Sep 4, 2026
Registry last updated
Sep 4, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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