Obstructive Sleep Apnea - Autonomic and Vascular Exploration (OSAVE)

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

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.

Study Overview

• Status: Terminated
• Conditions: Obstructive Sleep Apnea
• Intervention / Treatment: Other: CPAP withdrawal

• Study Type: Interventional
• Enrollment (Actual): 65
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Switzerland
  • Canton of Vaud
    • Lausanne, Canton of Vaud, Switzerland, 1012
      • Lausanne University Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

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.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: CPAP withdrawal; CPAP withdrawal for 2 weeks	Other: CPAP withdrawal; 2 weeks of CPAP withdrawal

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

Collaborators and Investigators

• Sponsor: Raphael Heinzer
• Investigators: Principal Investigator: Raphael Heinzer, Pr., Centre Hospitalier Universitaire Vaudois (CHUV)

Study record dates

Study Major Dates

• Study Start (Actual): January 12, 2024
• Primary Completion (Actual): September 11, 2024
• Study Completion (Actual): September 11, 2024

Study Registration Dates

• First Submitted: June 6, 2023
• First Submitted That Met QC Criteria: June 15, 2023
• First Posted (Actual): June 27, 2023

Study Record Updates

• Last Update Posted (Actual): December 12, 2025
• Last Update Submitted That Met QC Criteria: December 4, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: OSA; CPAP
• Additional Relevant MeSH Terms: Nervous System Diseases; Respiratory Tract Diseases; Respiration Disorders; Sleep Wake Disorders; Apnea; Sleep Disorders, Intrinsic; Dyssomnias; Sleep Apnea Syndromes; Sleep Apnea, Obstructive
• Other Study ID Numbers: 01012023

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No