Obstructive Sleep Apnea - Autonomic and Vascular Exploration

Study Overview
=================
Brief Summary
-----------------
The goal of this clinical trial is to assess the effect of CPAP withdrawal on vascular and autonomic function in patients with obstructive sleep apnea. The main question it aims to answer is: • Is the pulse wave amplitude index able to predict the impact of sleep apnea treatment withdrawal (continuous positive airway pressure, CPAP) on endothelial function and baroreflex sensitivity? Participants will stop using their CPAP for 2 weeks and the investigators will assess vascular and autonomic function before and after the withdrawal. Researchers will compare endothelial and autonomic function at baseline and after 2 weeks of withdrawal to see if there are differences. Moreover, they will assess the association between pulse wave amplitude drop profile and effect of CPAP withdrawal.

Official Title
-----------------
Noctural Pulse Waves Variations in OSA as a Predictor of Autonomic and Vascular Response to CPAP Therapy

Conditions
-----------------
Obstructive Sleep Apnea

Intervention / Treatment
-----------------
* Other: CPAP withdrawal


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Age ≥18 years old Diagnosed with OSA (AHI ≥15 events/h), confirmed during screening period Adequately treated with CPAP therapy for ≥6 months Able to give informed consent as documented by signature Exclusion Criteria: Professional drivers will be excluded from the study because temporary withdrawal of CPAP may induce drowsiness. We will also exclude patients with conditions that may affect endothelial and autonomic function: Known Diabetes Known heart failure Known chronic kidney disease Pregnant or lactating women Morbid obesity (≥40 kg/m2) Known Excessive alcohol consumption Known Dementia (especially dementia with Lewy bodies). (61) Patients using alpha and beta blockers Known atrial fibrillation Inability to follow the procedures of the study due to language problems or psychological disorders.

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Interventional Model Description: one group, before-after design
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: CPAP withdrawal<br>CPAP withdrawal for 2 weeks | Other: CPAP withdrawal<br>* 2 weeks of CPAP withdrawal<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in flow-mediated dilation | Endothelial function as measured with flow-mediated dilation | Between FMD measured after 2 weeks of CPAP withdrawal and FMD measured after 2 weeks on CPAP | 
| Change in the slope of baroreflex sensitivity | Autonomic function as measure with the slope of BRS | Between BRS measured after 2 weeks of CPAP withdrawal and BRS measured after 2 weeks on CPAP | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Arterial stiffness assessed by the pulse transit time | arterial stiffness measured by the pulse transit time | Baseline, after 2 weeks of withdrawal, after 2 weeks on CPAP | 
| Nocturnal heart rate variability indices (linear and non linear) | HRV measured on the ECG of polygraphy | baseline, after 2 weeks of withdrawal, after 2 weeks on CPAP | 
| Change in heart rate response to the cold pressure test | delta heart rate before and after cold pressure test | baseline, after 2 weeks of withdrawal, after 2 weeks on CPAP | 
| Hypoxic burden | hypoxic burden of sleep apnea based on polysomnography | baseline, after 2 weeks of withdrawal, after 2 weeks on CPAP | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
OSA, CPAP