ClinicalTrials.gg
Not yet recruitingNCT07804472Updated Sep 4, 2026

Assessment of Six-minute Walking Distance 6MWD Between High Altitude HA vs. Sea Level LA in Patients With Pulmonary Arterial Hypertension PAH

An interventional study of Descent from 2850m to sea level in Pulmonary Arterial Hypertension (PAH), Pulmonary Vascular Disease and Six-minute Walk Test, sponsored by Silvia Ulrich Somaini. Not yet recruiting at 1 site in Switzerland. Open to participants aged 18 Years to 80 Years. Per ClinicalTrials.gov, last updated 2026-09-04.

Sponsored by Silvia Ulrich Somaini · Not applicable, Interventional, and Supportive care

Phase
Not applicable
Study type
Interventional
Enrollment
20
Allocation
Not applicable
Ages
18 Years to 80 Years
Sex
All
01

Study summary

To study the effect of relocation from high altitude (Quito: 2850m) to sea level on six-minute walking distance and scores in patients with pulmonary arterial hypertension PAH, who live permanently >2600m.

Read the detailed description

The aim of this research is to investigate the six-minute walking distance and scores before and after descent (high altitude near their living altitude vs. sea level) in patients with diagnosed pulmonary arterial hypertension according to guidelines, who permanently live at high altitude over 2600m.

02

Conditions studied

  • Pulmonary Arterial Hypertension (PAH)
  • Pulmonary Vascular Disease
  • Six-minute Walk Test
  • High Altitude Effects
  • High Altitude

Keywords

  • Hypoxia
  • High Altitude
  • Pulmonary Hypertension
  • 6-minute walking distance
  • Pulmonary Arterial Hypertension
  • NYHA
03

In context

Pulmonary Arterial Hypertension

699 studies on the registry are indexed under Pulmonary Arterial Hypertension; 140 are open to participants now.

This study's planned enrollment of 20 is below the median of 40 across 477 interventional studies indexed under Pulmonary Arterial Hypertension.

Browse Pulmonary Arterial Hypertension studies →

Lead sponsor

Silvia Ulrich Somaini is the lead sponsor of 17 studies on the registry; 16 are open to participants now.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years to 80 Years
Sexes eligible
All
Accepts healthy volunteers
No

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

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
  • (new york heart association) functional class I-III
  • written to participate in the study

Exclusion criteria

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 (\<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 pulse-oximetry) \<80% on ambient air.
  • Patient with a non-corrected ventricular septum defect
  • Relevant concomitant other disease of the heart, kidney, liver, blood (anemia \<11 g/dl)
Terms in these criteria, in plain language(4)

Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.

NYHA class (heart failure)

The New York Heart Association’s four classes of how much heart failure limits physical activity.

I
No limits: ordinary activity causes no undue tiredness or breathlessness.
II
Slight limits: comfortable at rest, ordinary activity causes symptoms.
III
Marked limits: comfortable at rest, less than ordinary activity causes symptoms.
IV
Symptoms even at rest; any activity makes them worse.

Studies set their own limit — many outside heart failure leave out class III–IV, while heart failure studies may ask for a particular class. Check the class this study names.

Informed consent

Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.

You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.

FEV1

From a breathing test (spirometry): how much air you can blow out in the first second. Often given as a percentage of what is expected for your age, height and sex.

Hemoglobin (Hb)

The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).

05

Study design

Phase
Not applicable
Primary purpose
Supportive care
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrollment
20 participants (estimated)

Study arms

  • Experimental
    Six-minute walking distance 6MWD at 2850m and at sea level

    Assessment of the six-minute walking distance and scores near their resident altitude at 2850m followed by a descent from 2850m to sea level by bus with a stay for 7 days and again assessment of the same outcomes

    Behavioral: Descent from 2850m to sea level

Interventions

  • BehavioralDescent from 2850m to sea level

    Descent from 2850m to sea level with stay for 7 days

06

What researchers measure

Primary outcomes

  1. Six-minute walking distance (m) after 7 days at sea level

    Difference/change in six-minute walking distance 6MWD between 2850m and Day 5-7 at sea level in patients with pulmonary arterial hypertension

    Time frame: From high altitude (2850m) to day 5-7 at sea level

Secondary outcomes

  1. SpO2 (peripheral oxygen saturation, %) at rest and end-exercise after 7 days at sea level

    Difference/change in SpO2 (peripheral oxygen saturation) at rest and end-exercise between 2850m and Day 5-7 at sea level in patients with pulmonary arterial hypertension

    Time frame: From high altitude (2850m) to day 5-7 at sea level

  2. Heart rate (beats per minute) at rest and end-exercise after 7 days at sea level

    Difference/change in heart rate at rest and end-exercise between 2850m and Day 5-7 at sea level in patients with pulmonary arterial hypertension

    Time frame: From high altitude (2850m) to day 5-7 at sea level

  3. Blood pressure (mmHg) at rest and end-exercise after 7 days at sea level

    Difference/change in blood pressure at rest and end-exercise between 2850m and Day 5-7 at sea level in patients with pulmonary arterial hypertension

    Time frame: From high altitude (2850m) to day 5-7 at sea level

  4. Dyspnea and leg discomfort sensation after 7 days at sea level

    Difference/change in dyspnea and leg discomfort sensation (assessed with BORG-CR10-Scale, Category Rating 0-10 with 10 being the most dyspnea/leg discomfort) at rest and end-exercise between 2850m and 5-7 days at sea level in patients with pulmonary arterial hypertension

    Time frame: From high altitude (2850m) to day 5-7 at sea level

  5. NYHA functional class (1-4) after 7 days at sea level

    Difference/change in NYHA functional class (New York Heart Association Class I-IV, IV being the worst) at rest and end-exercise between 2850m and 5-7 days at sea level in patients with pulmonary arterial hypertension

    Time frame: From high altitude (2850m) to day 5-7 at sea level

  6. Quality of life after 7 days at sea level

    Difference/change in quality of life score (EmPHasis-10: Score with 10 questions and 0-50 points, higher scores indicating poorer quality of life) between 2850m and 5-7 days at sea level in patients with pulmonary arterial hypertension

    Time frame: From high altitude (2850m) to day 5-7 at sea level

  7. General well-being after 7 days at sea level

    Difference/change in general well-being (Visual Analog Scale 10cm: the higher, the worse) between 2850m and day 5-7 at sea level in patients with pulmonary arterial hypertension

    Time frame: From high altitude (2850m) to Day 5-7 at sea level

  8. Acclimatization-effect of six-minute walking distance (m) at sea level

    Difference/change in six-minute walking distance (6MWD) within a stay at sea level of 7 days (after descent from 2850m) in patients with pulmonary arterial hypertension

    Time frame: From Day 2 to Day 5-7 at sea level

  9. Acclimatization-Effect of SpO2 (%) at rest and end-exercise at sea level

    Difference/change in SpO2 (peripheral oxygen saturation) at rest and end-exercise within a stay at sea level of 7 days (after descent from 2850m) in patients with pulmonary arterial hypertension

    Time frame: From Day 2 to Day 5-7 at sea level

  10. Acclimatization-Effect of heart rate (beats per minute) at rest and end-exercise at sea level

    Difference/change in heart rate at rest and end-exercise within a stay at sea level of 7 days (after descent from 2850m) in patients with pulmonary arterial hypertension

    Time frame: From Day 2 to Day 5-7 at sea level

  11. Acclimatization-Effect of blood pressure (mmHg) at rest and end-exercise at sea level

    Difference/change in blood pressure at rest and end-exercise within a stay at sea level of 7 days (after descent from 2850m) in patients with pulmonary arterial hypertension

    Time frame: From Day 2 to Day 5-7 at sea level

  12. Acclimatization-Effect of dyspnea and leg discomfort at sea level

    Difference/change in dyspnea and leg discomfort (assessed with BORG-CR10-Scale, Category Rating 0-10 with 10 being the most dyspnea/leg discomfort) at rest and end-exercise within a stay at sea level of 7 days (after descent from 2850m) in patients with pulmonary arterial hypertension

    Time frame: From Day 2 to Day 5-7 at sea level

  13. Acclimatization-Effect of NYHA functional class (1-4) at sea level

    Difference/change in NYHA functional class (New York Heart Association Class I-IV, IV being the worst) at rest and end-exercise within a stay of 7 days at sea level (after descent from 2850m) in patients with pulmonary arterial hypertension

    Time frame: From Day 2 to Day 5-7 at sea level

  14. Acclimatization-Effect of Quality of Life at sea level

    Difference/change in quality of life (EmPHasis-10: Score with 10 questions and 0-50 points, higher scores indicating poorer quality of life) within a stay of 7 days at sea level (after descent from 2850m) in patients with pulmonary arterial hypertension

    Time frame: From Day 2 to Day 5-7 at sea level

  15. Acclimatization-Effect of general well-being at sea level

    Difference/change in general well-being (Visual Analog Scale 10cm: the higher, the worse) within a stay of 7 days at sea level (after descent from 2850m) in patients with pulmonary arterial hypertension

    Time frame: From Day 2 to Day 5-7 at sea level

07

Study locations

1 site
08

References and documents

Individual participant data

Plan to share: Yes — Data will be provided upon request and based on a clear intention reviewed by an ethical review board.

No publications or documents are linked to this record.

09

Timeline

Tracking since Sep 25, 2026
ElapsedEstimatedEstimated, not yet reachedSimilar studies: half by the dot; the band is the middle halfHalf of similar studies reached it by the dot; the band is the middle half, from a quarter to three quarters

Start is estimated for Sep 2026; primary completion for Oct 2026, 0 months later.

Of 60 non-industry interventional studies with no phase under Pulmonary Arterial Hypertension, half reached primary completion within 44 months of starting (the median), counting those still running; a quarter within 18 and three quarters within 63. This study's planned 0 months is below that.

Counting every sponsor, half of 65 studies reached it within 42 months; a quarter within 18 and three quarters within 71.

How these figures are worked out, and which studies are left out of them.

Registered
Aug 17, 2026
First posted
Sep 4, 2026
StartEst.
Sep 25, 2026
Primary completionEst.
Oct 4, 2026
CompletionEst.
Dec 31, 2026
Last update
Sep 4, 2026
What these dates mean
Start.
When the first participant enrolled; while estimated, when the study expects to open to recruitment.
Primary completion.
When the last participant was examined or treated to collect data for the study's main question, its primary outcome. A study that stopped early gives the date its data collection stopped.
Completion.
When the last participant's last visit took place, for every outcome, secondary ones and side effects included: the end of the study. Often later than primary completion, sometimes the same day.
Actual and Est.
Actual means the registry says the date has happened. Est. (estimated) is a date the sponsor plans or expects. It can still move, and the sponsor is expected to change it to actual once it has passed.
No changes since tracking began. The registry record was last updated on Sep 4, 2026, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT07804472
Lead sponsor
Silvia Ulrich Somaini
Responsible party
Silvia Ulrich Somaini (Prof. Dr. med., University of Zurich) — Sponsor-investigator
First posted
Sep 4, 2026
Start date
Sep 25, 2026 (estimated)
Primary completion
Oct 4, 2026 (estimated)
Completion
Dec 31, 2026 (estimated)
Last update
Sep 4, 2026

Study contacts

Silvia Ulrich, Prof. Dr. med.
Contact
silvia.ulrich@usz.ch
+41442552220
Michael Furian, Prof. Dr. sc. ETH
Contact
+41442552220
Silvia Ulrich
principal investigator · University Hospital Zurich, Departement of Pulmonology
Rodrigo Hoyos
principal investigator · Hospital Carlos Andrade Marin of Quito, Ecuador

Oversight

Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

Not currently enrolling

This study is not yet recruiting, as verified in Aug 2026. You cannot join it, but the record below documents what was studied.

Follow this study

Get an email when the registry record changes — status, dates, results — or when someone posts here.

Sign in to follow

Discussion

Questions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.

Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.

Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.

Start the discussion