Cerebral Tissue Oxygenation in Highlanders/Lowlanders

Study Overview
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Brief Summary
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The purpose of the current study is to evaluate the cerebral tissue oxygenation of Kyrgyz highlanders with high altitude pulmonary hypertension (HAPH) by performing a longitudinal cohort study. To this end, the investigators will invite the same highlanders who participated in the study in 2012 to undergo follow-up examinations in 2017, in order to allow comparisons of current results with baseline data from 2012.

Official Title
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Cerebral Tissue Oxygenation in Highlanders With Pulmonary Hypertension Compared to Highlanders Without Pulmonary Hypertension and Lowlanders

Conditions
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High Altitude Pulmonary Hypertension

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: high altitude pulmonary hypertension confirmed by clinical presentation and mean pulmonary artery pressure >30 mmHg measured by echocardiography at altitude of residence. healthy subjects (high altitude controls) Both genders Age >16 y Kyrgyz ethnicity born, raised and currently living at >2500 m healthy subjects currently living at <1000 m (low altitude controls) Exclusion Criteria: Pulmonary hypertension from other causes, in particular from left ventricular failure as judged clinically and by echocardiography Excessive erythrocytosis Other coexistent disorders that may interfere with the cardio-respiratory system and sleep Regular use of medication that affects control of breathing Heavy smoking

Ages Eligible for Study
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Minimum Age: 16 Years

Sexes Eligible for Study
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All

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| High altitude pulmonary hypertension<br>Highlanders with high altitude pulmonary hypertension living above 2500 m. | |
| High altitude control<br>Healthy highlanders living above 2500 m. | |
| Low altitude control<br>Healthy lowlanders living below 1000 m. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in cerebral tissue oxygenation | Difference in the change in cerebral tissue oxygenation (CTO, measured by near infrared spectroscopy) 2012 to 2017 in highlanders with high altitude pulmonary hypertension, healthy highlanders and healthy lowlander | Year 2012 to 2017 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in cerebrovascular response to hyperoxia | Difference in the change in cerebrovascular response (total hemoglobin concentration, a surrogate to blood volume, measured by near infrared spectroscopy) to hyperoxia 2012 to 2017 in highlanders with high altitude pulmonary hypertension, healthy highlanders and healthy lowlander | Year 2012 to 2017 | 
| Changes in cerebrovascular response to hypocapnia | Difference in the change in cerebrovascular response (total hemoglobin concentration, a surrogate to blood volume, measured by near infrared spectroscopy) to hypocapnia 2012 to 2017 in highlanders with high altitude pulmonary hypertension, healthy highlanders and healthy lowlander | Year 2012 to 2017 | 
| Arterial oxygen saturation | Difference in the change in the arterial oxygen saturation 2012 to 2017 in highlanders with high altitude pulmonary hypertension, healthy highlanders and healthy lowlander | Year 2012 to 2017 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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pulmonary hypertension, cerebral tissue oxygenation, disease progression, hypoxia