Aortic StenosisASALTNCT06894550
Short-term Exposure to High Altitude in Patients With Asymptomatic Aortic Stenosis
A study testing Participants will be escorted to high altitude and undergo a series of test in people with Aortic Stenosis and Altitude, run by Insel Gruppe AG, University Hospital Bern at 1 site in Switzerland.
Trial summary
Aortic stenosis is a common disease with increasing prevalence due to an aging population. Aortic valve replacement is indicated for symptomatic severe aortic stenosis. Leisure activities and tourism at high altitude destinations are popular but may impose a higher risk to patients with aortic stenosis. Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Aortic Stenosis, Altitude
- What is being tested?
- Participants will be escorted to high altitude and undergo a series of test
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 41 participants
- Where
- 1 siteSwitzerland
- Study dates
- 1 Mar 2025to 6 Jul 2026
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Group 1:
- Moderate or severe aortic stenosis (aortic valve area (AVA) ≤1.5 cm2)
- NYHA class I
- LVEF > 50%
- Aortic stenosis staging classification Stage 0 or 1
- Written informed consent
Show all 18Show fewer
- Group 2:
- Aortic stenosis s/p aortic valve replacement within 1 year
- NYHA class I
- LVEF > 50%
- Aortic stenosis staging classification Stage 0 or 1
- Written informed consent
- Group 3:
- NYHA class I
- LVEF >50%
- No evidence of valvular heart disease
- Age > 65 years
- Written informed consent
Who cannot join
- NYHA class > I (all groups)
- History of cardiac decompensation requiring hospitalization (all groups)
- Uncontrolled arterial hypertension (>180/100 mmHg at rest) (all groups)
- Other Cardiomyopathies w/ normal LVEF (dilatative, hypertrophic, infiltrative CMP) (all groups)
- Signs of exercise-induced ischemia (ST-segment depression > 2 mV), hemodynamic instability (drop in systolic blood pressure > 20 mmHg and systolic blood pressure ≤ 100 mmHg), or ventricular arrhythmias (> 5 beats) during cardiopulmonary stress exercise testing (CPET) at Bern (540 meters) (all groups)
- Chronic obstructive pulmonary disease with a forced expiratory volume in 1 second (FEV1) <60% of the predicted (all groups)
Show all 16Show fewer
- Known pulmonary hypertension with a pulmonary artery systolic pressure >50 mmHg or high probability of pulmonary hypertension as assessed in TTE (all groups)
- NT-pro BNP levels > 900 pg/ml (all groups)
- Aortic stenosis staging classification > Stage 1 (group 1 and 2)
- History of advanced stages of acute mountain sickness defined as high altitude pulmonary (HAPE) or cerebral (HACE) edema (all groups)
- Transvalvular gradient across the aortic valve ≥60 mmHg, Vmax >5 m/s (group 1)
- Vmax progression ≥0.3 m/s/year (group 1)
- Transvalvular gradient across the aortic valve ≥20 mmHg (group 2)
- Evidence of valvular heart disease or coronary artery disease (group 3)
- History of rhythm disturbances (other than premature ventricular contraction (PVC) (group 3)
- Right ventricular dysfunction, defined as TAPSE < 17 mm, s'DTI < 9 cm/sec (all groups)
Trial locations and contacts
1 site in 1 country.
Switzerland1 site
University Hospital Inselspital, Bern
Bern, Canton of Bern, CH-3010
About this study
Aortic stenosis is a common disease with increasing prevalence due to an aging population. Aortic valve replacement is indicated for symptomatic severe aortic stenosis. Leisure activities and tourism at high altitude destinations are popular but may impose a higher risk to patients with aortic stenosis. Pathophysiological considerations led to an expert consensus to avoid high altitude exposure, though there is no robust scientific evidence.
Hence, the objective of this study is to evaluate the safety of high altitude exposure in patients with asymptomatic moderate or severe aortic stenosis by the measurement of surrogate markers for cardiac adverse events such as the decrease in exercise capacity, the assessment of changes in cardiac filling pressures, cardiac dimensions and function, and the evaluation of the incidence of cardiac arrhythmia.
Read the detailed description
- Hemodynamic changes of high altitude exposure
Atmospheric pressure exponentially decreases with increasing altitude and results in hypobaric hypoxia and arterial hypoxemia. Adaptive mechanisms to high altitude involve the cardiovascular, pulmonary and metabolic system and result in important hemodynamic changes. Acute hypoxia is associated with an increase in cardiac output, heart rate, myocardial contractility, and blood pressure. At the same time, pulmonary vasoconstriction increases pulmonary pressure and right ventricular afterload, while systemic vasodilatation improves peripheral oxygen delivery to the tissues. Hyperventilation furthermore results in respiratory alkalosis and may precipitate premature ventricular complexes and cardiac arrhythmia.
- High altitude exposure in individuals with cardiovascular disease
A range of physiological responses to the high altitude environment challenge the cardiovascular system and potentially increase the risk of adverse cardiovascular events. Pre-existing heart disease can mitigate compensatory mechanisms required for physiological adaption to high altitude. Available evidence is however scarce, which is reflected by the vague clinical recommendations of the European Society of Cardiology and the American Heart Association. Previous evidence suggested that short-term exposure to 3454 meters above sea level was well tolerated in patients with coronary artery disease, stable heart failure and congenital heart disease. There is however no clinical data on the effects of high altitude exposure in patients with valvular heart disease. Expert consensus, based on hemodynamic and pathophysiological considerations, states that patients with symptomatic and/or severe aortic stenosis are prohibited from high altitude exposure/activities.
- Aortic stenosis
Aortic stenosis is the second most prevalent valvular heart disease in the Western World and increases with advancing age. Moderate or severe aortic stenosis was documented in 0.7% of individuals aged ≥65 years in a large-scale community-bases echocardiographic screening program in the United Kingdom, and accounts for more than two thirds of deaths due to degenerative valvular heart disease. The degenerative origin of the disease forecasts an increasing incidence of aortic stenosis in the aging population. An increase in afterload due to aortic valve stenosis leads to an increase in left ventricular pressure and left ventricular wall stress according to the Law of LaPlace. Concentric hypertrophy and an increase in left ventricular mass result in an increased oxygen consumption and a reduction in coronary flow reserve. Upstream cardiac damage may result in mitral regurgitation, left atrial enlargement, pulmonary hypertension, tricuspid regurgitation, and eventually right ventricular dysfunction. The natural history of aortic stenosis is characterized by a long asymptomatic course. Aortic valve replacement is indicated when symptoms such as exercise intolerance, shortness of breath, exertional chest pain or dizziness with syncope develop. Timing of intervention is transitioning from grading of disease according to transvalvular gradients to staging of disease reflecting secondary cardiac damage as a consequence of afterload increase.
- High altitude exposure of individuals with aortic stenosis
Several mechanisms may compromise the short-term adaptation of patients with aortic stenosis to high altitude. An increased oxygen demand of the hypertrophied left ventricle is exacerbated by the hypobaric hypoxia at altitude and may results in myocardial ischemia. This process may be further amplified by an increase in heart rate, and entertain a vicious cycle of myocardial ischemia. At the same time, tachycardia with corresponding increase in cardiac output may aggravate aortic stenosis and precipitate cardiac decompensation. Peripheral vasodilatation may furthermore cause hypotension which is poorly tolerated in aortic stenosis.
- Research question and rationale
Top of Europe/Jungfraujoch located at 3454 meters altitude above sea level is easily accessible by railroad, and visited by more than 1 million tourists every year. Outside of Europe, other tourist hot spots such as Lhasa in Tibet (3658 meters), La Paz in Bolivia (3640 meters), or Cusco in Peru (3399 meters) attract millions of tourists every year. In addition, more than 25 million people worldwide permanently live at an altitude ≥3000 meters. In the absence of robust scientific evidence, even patients with asymptomatic aortic stenosis are discouraged from travelling to high altitude due to hemodynamic considerations. However, data from the Oxvalve registry indicates, that significant valvular heart disease is undiagnosed in 2 out of 3 patients. It can therefore be assumed, that many patients with relevant aortic stenosis travel to high altitude every year without being aware of potential risks.
The goal of the present study is to evaluate the hemodynamic response of patients with asymptomatic moderate or severe aortic stenosis to high altitude, and to assess the safety of high altitude exposure in patients with aortic stenosis. The present study would be the first study to assess the safety of high altitude exposure in patients with aortic stenosis.
- Conditions
- Aortic Stenosis, Altitude
- Being tested
- Participants will be escorted to high altitude and undergo a series of test
- Keywords
- Aortic stenosis, High altitude
- Medical subject headings
- Aortic Valve Stenosis, Altitude Sickness
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Participants will be escorted to high altitude and undergo a series of testBehavioural
Participants will be escorted to high altitude and undergo the following examination both at 540 and 3545m above sea level:
- 12-lead electrocardiogram
- Transthoracic echocardiography with measurement of left and right ventricular dimension and function, global longitudinal strain and transvalvular gradient
- Symptom-limited cardiopulmonary stress exercise test with a ramp protocol with a focused echocardiography for the assessment of cardiac output and transvalvular gradient and blood gas analysis
- 24 hours wearable rhythm monitoring
- Blood Work: cardiac biomarkers (Troponin T, CK, CK-MB, NT-pro-BNP), blood gas analysis, Hemoglobin, Hematocrit, Leucocytes, Thrombocytes, Creatinin, eGFR, Sodium, Potassium, ASAT, ALAT, Bilirubin)
| Study group | Role | What they receive |
|---|---|---|
| Patients with asymptomatic moderate or severe aortic stenosis | Experimental | Patients with asymptomatic moderate or severe aortic stenosis (moderate or severe aortic stenosis (aortic valve area (AVA) ≤1.5 cm2, NYHA class I, LVEF > 50%, aortic stenosis staging classification Stage 0 or 1) Receives: Behavioral: Participants will be escorted to high altitude and undergo a series of test |
| Patients with aortic stenosis s/p aortic valve replacement | Active comparator | Patients with aortic stenosis s/p aortic valve replacement (aortic stenosis s/p aortic valve replacement within 1 year, NYHA class I , LVEF > 50%, aortic stenosis staging classification Stage 0 or 1) Receives: Behavioral: Participants will be escorted to high altitude and undergo a series of test |
| Age- and sex-matched healthy individuals | Active comparator | Age- and sex-matched healthy individuals ( NYHA class I, LVEF >50%, no evidence of valvular heart disease, age > 65 years) Receives: Behavioral: Participants will be escorted to high altitude and undergo a series of test |
What is being measured
The primary outcome is the main question the study is designed to answer.
Safety of high altitude exposure in patients with asymptomatic moderate or severe aortic stenosis. Spiroergometry outcome 1
Decrease in VO2 peak, i.e. VO2-peak @high altitude minus VO2-peak @ low altitude
Measured: At end of the investigation at 3545m above sea level, expected to be on average after 3-4 hours
Safety of high altitude exposure in patients with asymptomatic moderate or severe aortic stenosis. Spiroergometry outcome 2
Increase in VE/VCO2 slope, i.e. VE/VCO2 slope @high altitude minus VE/VCO2 slope @ low altitude
Measured: At end of the investigation at 3545m above sea level, expected to be on average after 3-4 hours
Safety of high altitude exposure in patients with asymptomatic moderate or severe aortic stenosis. Echocardiography outcome 1
Decrease in Cardiac output, i.e. CO @high altitude minus CO @ low altitude
Measured: At end of the investigation at 3545m above sea level, expected to be on average after 3-4 hours
Safety of high altitude exposure in patients with asymptomatic moderate or severe aortic stenosis. Echocardiography outcome 2
Increase in left ventricular filling pressure (E/e'), i.e. E/e' @high altitude minus E/e' @ low altitude
Measured: At end of the investigation at 3545m above sea level, expected to be on average after 3-4 hours
Safety of high altitude exposure in patients with asymptomatic moderate or severe aortic stenosis. Rhythmologic outcome
Occurrence of ventricular tachycardia (> 3 beats). Evaluated as presence versus absence.
Measured: At end of the investigation at 3545m above sea level, expected to be on average after 3-4 hours
Secondary outcomes (4)
Symptoms associated with the high altitude exposure
Clinical symptoms of congestive heart failure (NYHA functional class III/IV): Number of patients with newly developed symptoms at high altitude
Measured: At end of the investigation at 3545m above sea level, expected to be on average after 3-4 hours
Laboratory values associated with the high altitude exposure
Increase in NT-proBNP levels. Measurement = NTproBNP @high altitude minus NTproBNP @ low altitude
Measured: At end of the investigation at 3545m above sea level, expected to be on average after 3-4 hours
Arrhythmia associated with the high altitude exposure
Supraventricular or ventricular tachycardia. Number of patients with arrhythmia associated with the high altitude exposure
Measured: At end of the investigation at 3545m above sea level, expected to be on average after 3-4 hours
Hemodynamic effect of the high altitude exposure
Drop in blood pressure (> 20 mmHg). Number of participants with a drop in blood pressure of >20mmHg.
Measured: At end of the investigation at 3545m above sea level, expected to be on average after 3-4 hours
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted25 Mar 2025
- Study start1 Mar 2025
- Primary completion3 Jul 2026
- Study completion6 Jul 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (3)Papers the sponsor has linked to this study.
- Other trials for Aortic StenosisStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Model description
- Prospective, monocentric, three-arm cohort study Group 1: Patients with asymptomatic moderate or severe aortic stenosis Group 2: Patients with aortic stenosis s/p aortic valve replacement Group 3: Age- and sex-matched healthy individuals
- Masking
- None (open label)
- Enrolment
- 41 participants (actual)
Sponsor and investigators
- Lead sponsor
- Insel Gruppe AG, University Hospital Bern
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Thomas Pilgrim, MD, MSc, Study chair, University Hospital of Bern, Bern, Switzerland
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06894550
- Sponsor's protocol ID
- 2024-00126
- Acronym
- ASALT
- Status last verified
- Jul 2026
- First submitted
- 11 Mar 2025
- Last updated
- 22 Jul 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Rimoldi SF, Sartori C, Seiler C, Delacretaz E, Mattle HP, Scherrer U, Allemann Y. High-altitude exposure in patients with cardiovascular disease: risk assessment and practical recommendations. Prog Cardiovasc Dis. 2010 May-Jun;52(6):512-24. doi: 10.1016/j.pcad.2010.03.005.
PubMed 20417345Schmid JP, Nobel D, Brugger N, Novak J, Palau P, Trepp A, Wilhelm M, Saner H. Short-term high altitude exposure at 3454 m is well tolerated in patients with stable heart failure. Eur J Heart Fail. 2015 Feb;17(2):182-6. doi: 10.1002/ejhf.227. Epub 2015 Jan 19.
PubMed 25597947Schmid JP, Noveanu M, Gaillet R, Hellige G, Wahl A, Saner H. Safety and exercise tolerance of acute high altitude exposure (3454 m) among patients with coronary artery disease. Heart. 2006 Jul;92(7):921-5. doi: 10.1136/hrt.2005.072520. Epub 2005 Dec 9.
PubMed 16339809
Study at a glance
From the registry record, last updated by the sponsor on 22 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Short-term Exposure to High Altitude in Patients With Asymptomatic Aortic Stenosis
- ClinicalTrials.gov ID
- NCT06894550
- Acronym / sponsor ID
- ASALT / 2024-00126
- Conditions
- Aortic Stenosis, Altitude
- Keywords
- Aortic stenosis, High altitude
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 41 participants (actual)
- Lead sponsor
- Insel Gruppe AG, University Hospital BernUniversity, hospital or other
- Study start
- 1 Mar 2025 (actual)
- Primary completion
- 3 Jul 2026 (actual)
- Study completion
- 6 Jul 2026 (actual)
- First posted
- 25 Mar 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Aortic stenosis is a common disease with increasing prevalence due to an aging population. Aortic valve replacement is indicated for symptomatic severe aortic stenosis. Leisure activities and tourism at high altitude destinations are popular but may impose a higher risk to patients with aortic stenosis. Pathophysiological considerations led to an expert consensus to avoid high altitude exposure, though there is no robust scientific evidence.
Hence, the objective of this study is to evaluate the safety of high altitude exposure in patients with asymptomatic moderate or severe aortic stenosis by the measurement of surrogate markers for cardiac adverse events such as the decrease in exercise capacity, the assessment of changes in cardiac filling pressures, cardiac dimensions and function, and the evaluation of the incidence of cardiac arrhythmia.
Detailed description
- Hemodynamic changes of high altitude exposure
Atmospheric pressure exponentially decreases with increasing altitude and results in hypobaric hypoxia and arterial hypoxemia. Adaptive mechanisms to high altitude involve the cardiovascular, pulmonary and metabolic system and result in important hemodynamic changes. Acute hypoxia is associated with an increase in cardiac output, heart rate, myocardial contractility, and blood pressure. At the same time, pulmonary vasoconstriction increases pulmonary pressure and right ventricular afterload, while systemic vasodilatation improves peripheral oxygen delivery to the tissues. Hyperventilation furthermore results in respiratory alkalosis and may precipitate premature ventricular complexes and cardiac arrhythmia.
- High altitude exposure in individuals with cardiovascular disease
A range of physiological responses to the high altitude environment challenge the cardiovascular system and potentially increase the risk of adverse cardiovascular events. Pre-existing heart disease can mitigate compensatory mechanisms required for physiological adaption to high altitude. Available evidence is however scarce, which is reflected by the vague clinical recommendations of the European Society of Cardiology and the American Heart Association. Previous evidence suggested that short-term exposure to 3454 meters above sea level was well tolerated in patients with coronary artery disease, stable heart failure and congenital heart disease. There is however no clinical data on the effects of high altitude exposure in patients with valvular heart disease. Expert consensus, based on hemodynamic and pathophysiological considerations, states that patients with symptomatic and/or severe aortic stenosis are prohibited from high altitude exposure/activities.
- Aortic stenosis
Aortic stenosis is the second most prevalent valvular heart disease in the Western World and increases with advancing age. Moderate or severe aortic stenosis was documented in 0.7% of individuals aged ≥65 years in a large-scale community-bases echocardiographic screening program in the United Kingdom, and accounts for more than two thirds of deaths due to degenerative valvular heart disease. The degenerative origin of the disease forecasts an increasing incidence of aortic stenosis in the aging population. An increase in afterload due to aortic valve stenosis leads to an increase in left ventricular pressure and left ventricular wall stress according to the Law of LaPlace. Concentric hypertrophy and an increase in left ventricular mass result in an increased oxygen consumption and a reduction in coronary flow reserve. Upstream cardiac damage may result in mitral regurgitation, left atrial enlargement, pulmonary hypertension, tricuspid regurgitation, and eventually right ventricular dysfunction. The natural history of aortic stenosis is characterized by a long asymptomatic course. Aortic valve replacement is indicated when symptoms such as exercise intolerance, shortness of breath, exertional chest pain or dizziness with syncope develop. Timing of intervention is transitioning from grading of disease according to transvalvular gradients to staging of disease reflecting secondary cardiac damage as a consequence of afterload increase.
- High altitude exposure of individuals with aortic stenosis
Several mechanisms may compromise the short-term adaptation of patients with aortic stenosis to high altitude. An increased oxygen demand of the hypertrophied left ventricle is exacerbated by the hypobaric hypoxia at altitude and may results in myocardial ischemia. This process may be further amplified by an increase in heart rate, and entertain a vicious cycle of myocardial ischemia. At the same time, tachycardia with corresponding increase in cardiac output may aggravate aortic stenosis and precipitate cardiac decompensation. Peripheral vasodilatation may furthermore cause hypotension which is poorly tolerated in aortic stenosis.
- Research question and rationale
Top of Europe/Jungfraujoch located at 3454 meters altitude above sea level is easily accessible by railroad, and visited by more than 1 million tourists every year. Outside of Europe, other tourist hot spots such as Lhasa in Tibet (3658 meters), La Paz in Bolivia (3640 meters), or Cusco in Peru (3399 meters) attract millions of tourists every year. In addition, more than 25 million people worldwide permanently live at an altitude ≥3000 meters. In the absence of robust scientific evidence, even patients with asymptomatic aortic stenosis are discouraged from travelling to high altitude due to hemodynamic considerations. However, data from the Oxvalve registry indicates, that significant valvular heart disease is undiagnosed in 2 out of 3 patients. It can therefore be assumed, that many patients with relevant aortic stenosis travel to high altitude every year without being aware of potential risks.
The goal of the present study is to evaluate the hemodynamic response of patients with asymptomatic moderate or severe aortic stenosis to high altitude, and to assess the safety of high altitude exposure in patients with aortic stenosis. The present study would be the first study to assess the safety of high altitude exposure in patients with aortic stenosis.
Study design
- Primary purpose
- Basic science
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 3
- Model description
- Prospective, monocentric, three-arm cohort study Group 1: Patients with asymptomatic moderate or severe aortic stenosis Group 2: Patients with aortic stenosis s/p aortic valve replacement Group 3: Age- and sex-matched healthy individuals
| Arm | Type | Receives |
|---|---|---|
| Patients with asymptomatic moderate or severe aortic stenosis | Experimental | Behavioral: Participants will be escorted to high altitude and undergo a series of testPatients with asymptomatic moderate or severe aortic stenosis (moderate or severe aortic stenosis (aortic valve area (AVA) ≤1.5 cm2, NYHA class I, LVEF > 50%, aortic stenosis staging classification Stage 0 or 1) |
| Patients with aortic stenosis s/p aortic valve replacement | Active comparator | Behavioral: Participants will be escorted to high altitude and undergo a series of testPatients with aortic stenosis s/p aortic valve replacement (aortic stenosis s/p aortic valve replacement within 1 year, NYHA class I , LVEF > 50%, aortic stenosis staging classification Stage 0 or 1) |
| Age- and sex-matched healthy individuals | Active comparator | Behavioral: Participants will be escorted to high altitude and undergo a series of testAge- and sex-matched healthy individuals ( NYHA class I, LVEF >50%, no evidence of valvular heart disease, age > 65 years) |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (18 listed)
- Moderate or severe aortic stenosis (aortic valve area (AVA) ≤1.5 cm2)
- NYHA class I
- LVEF > 50%
- Aortic stenosis staging classification Stage 0 or 1
- Written informed consent
Key exclusion criteria (16 listed)
- NYHA class > I (all groups)
- History of cardiac decompensation requiring hospitalization (all groups)
- Uncontrolled arterial hypertension (>180/100 mmHg at rest) (all groups)
- Other Cardiomyopathies w/ normal LVEF (dilatative, hypertrophic, infiltrative CMP) (all groups)
- Signs of exercise-induced ischemia (ST-segment depression > 2 mV), hemodynamic instability (drop in systolic blood pressure > 20 mmHg and systolic blood pressure ≤ 100 mmHg), or ventricular arrhythmias (> 5 beats) during cardiopulmonary stress exercise testing (CPET) at Bern (540 meters) (all groups)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Participants will be escorted to high altitude and undergo a series of testParticipants will be escorted to high altitude and undergo the following examination both at 540 and 3545m above sea level: * 12-lead electrocardiogram * Transthoracic echocardiography with measurement of left and right ventricular dimension and function, global longitudinal strain and transvalvular gradient * Symptom-limited cardiopulmonary stress exercise test with a ramp protocol with a focused echocardiography for the assessment of cardiac output and transvalvular gradient and blood gas analysis * 24 hours wearable rhythm monitoring * Blood Work: cardiac biomarkers (Troponin T, CK, CK-MB, NT-pro-BNP), blood gas analysis, Hemoglobin, Hematocrit, Leucocytes, Thrombocytes, Creatinin, eGFR, Sodium, Potassium, ASAT, ALAT, Bilirubin) | Behavioural | Age- and sex-matched healthy individuals, Patients with aortic stenosis s/p aortic valve replacement, Patients with asymptomatic moderate or severe aortic stenosis |
Primary outcome
Safety of high altitude exposure in patients with asymptomatic moderate or severe aortic stenosis. Spiroergometry outcome 1
Time frame: At end of the investigation at 3545m above sea level, expected to be on average after 3-4 hours
Decrease in VO2 peak, i.e. VO2-peak @high altitude minus VO2-peak @ low altitude
Safety of high altitude exposure in patients with asymptomatic moderate or severe aortic stenosis. Spiroergometry outcome 2
Time frame: At end of the investigation at 3545m above sea level, expected to be on average after 3-4 hours
Increase in VE/VCO2 slope, i.e. VE/VCO2 slope @high altitude minus VE/VCO2 slope @ low altitude
Safety of high altitude exposure in patients with asymptomatic moderate or severe aortic stenosis. Echocardiography outcome 1
Time frame: At end of the investigation at 3545m above sea level, expected to be on average after 3-4 hours
Decrease in Cardiac output, i.e. CO @high altitude minus CO @ low altitude
Safety of high altitude exposure in patients with asymptomatic moderate or severe aortic stenosis. Echocardiography outcome 2
Time frame: At end of the investigation at 3545m above sea level, expected to be on average after 3-4 hours
Increase in left ventricular filling pressure (E/e'), i.e. E/e' @high altitude minus E/e' @ low altitude
Safety of high altitude exposure in patients with asymptomatic moderate or severe aortic stenosis. Rhythmologic outcome
Time frame: At end of the investigation at 3545m above sea level, expected to be on average after 3-4 hours
Occurrence of ventricular tachycardia (> 3 beats). Evaluated as presence versus absence.
4 secondary outcomes
Symptoms associated with the high altitude exposure
Time frame: At end of the investigation at 3545m above sea level, expected to be on average after 3-4 hours
Laboratory values associated with the high altitude exposure
Time frame: At end of the investigation at 3545m above sea level, expected to be on average after 3-4 hours
Arrhythmia associated with the high altitude exposure
Time frame: At end of the investigation at 3545m above sea level, expected to be on average after 3-4 hours
Hemodynamic effect of the high altitude exposure
Time frame: At end of the investigation at 3545m above sea level, expected to be on average after 3-4 hours
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 22 Jul 2026.
- Background: PubMed 20417345Rimoldi SF, Sartori C, Seiler C, Delacretaz E, Mattle HP, Scherrer U, Allemann Y. High-altitude exposure in patients with cardiovascular disease: risk assessment and practical recommendations. Prog Cardiovasc Dis. 2010 May-Jun;52(6):512-24. doi: 10.1016/j.pcad.2010.03.005.
- Background: PubMed 25597947Schmid JP, Nobel D, Brugger N, Novak J, Palau P, Trepp A, Wilhelm M, Saner H. Short-term high altitude exposure at 3454 m is well tolerated in patients with stable heart failure. Eur J Heart Fail. 2015 Feb;17(2):182-6. doi: 10.1002/ejhf.227. Epub 2015 Jan 19.
- Background: PubMed 16339809Schmid JP, Noveanu M, Gaillet R, Hellige G, Wahl A, Saner H. Safety and exercise tolerance of acute high altitude exposure (3454 m) among patients with coronary artery disease. Heart. 2006 Jul;92(7):921-5. doi: 10.1136/hrt.2005.072520. Epub 2005 Dec 9.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Thomas Pilgrim, MD, MSc study chair
University Hospital of Bern, Bern, Switzerland
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Participants will be escorted to high altitude and undergo a series of test in people with Aortic Stenosis and Altitude, run by Insel Gruppe AG, University Hospital Bern at 1 site in Switzerland.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 18 inclusion and 16 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 22 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Switzerland. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Safety of high altitude exposure in patients with asymptomatic moderate or severe aortic stenosis. Spiroergometry outcome 1 (time frame: At end of the investigation at 3545m above sea level, expected to be on average after 3-4 hours). The study lists 5 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT06894550, which also lists 3 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 22 Jul 2026.