The Effects of CPAP Withdrawal on Cerebral Vascular Reactivity and Brain Oxygenation in OSA

Sponsor

University of Zurich (Other)

Overall Status

Completed

CT.gov ID

NCT02493673

Collaborator

(none)

Enrollment

Location

Arms

Duration (Months)

1.6

Patients Per Site Per Month

Study Details

Study Description

Brief Summary

Obstructive sleep apnoea (OSA) is a highly prevalent sleep-related breathing disorder associated with adverse cardiovascular outcome. Underlying mechanisms are subject of debate. A causal relationship between OSA and systemic hypertension as well as peripheral endothelial dysfunction was shown, and there is accumulating evidence from physiologic and observational studies that cerebral autoregulation is insufficient to protect the brain from the nocturnal consequences of OSA. However, there are no data from randomised controlled trials proving a causal relationship between OSA and impaired cerebral vascular reactivity (CVR). The aim of this randomised controlled trial is to study the effects of a short-term CPAP withdrawal, and thus returning OSA, on daytime CVR and brain oxygenation to establish whether there is a causal relationship between OSA and cerebral vascular damage.

Condition or Disease	Intervention/Treatment	Phase
Sleep Apnea, Obstructive	Device: Continuous positive airway pressure device	N/A

Study Design

Study Type:

Interventional

Actual Enrollment :

49 participants

Allocation:

Randomized

Intervention Model:

Parallel Assignment

Masking:

Double (Participant, Outcomes Assessor)

Primary Purpose:

Other

Official Title:

The Effects of Continuous Positive Airway Pressure Therapy Withdrawal on Cerebral Vascular Reactivity and Brain Oxygenation in Patients With Obstructive Sleep Apnoea: A Randomised Controlled Trial

Study Start Date :

Jun 1, 2015

Actual Primary Completion Date :

Dec 1, 2017

Actual Study Completion Date :

Dec 1, 2017

Arms and Interventions

Arm	Intervention/Treatment
Active Comparator: CPAP therapy Continuous positive airway pressure therapy	Device: Continuous positive airway pressure device (ResMed Spirit S8)
Sham Comparator: Sham CPAP Sham- Continuous positive airway pressure	Device: Continuous positive airway pressure device (ResMed Spirit S8)

Arm

Intervention/Treatment

Active Comparator: CPAP therapy

Continuous positive airway pressure therapy

Device: Continuous positive airway pressure device

(ResMed Spirit S8)

Sham Comparator: Sham CPAP

Sham- Continuous positive airway pressure

Device: Continuous positive airway pressure device

(ResMed Spirit S8)

Outcome Measures

Primary Outcome Measures

Cerebrovascular reactivity (CVR) [Change from baseline in CVR after 2 weeks of CPAP withdrawal]
CVR measured non-invasively by blood oxygen level-dependent (BOLD) magnetic resonance imaging (MRI) under controlled cardiovascular reactivity stimulation during wakefulness

Secondary Outcome Measures

Ambulatory morning blood pressure [Change from baseline in ambulatory morning blood pressure after 2 weeks of CPAP withdrawal]
Resting heart rate [Change from baseline in resting heart rate after 2 weeks of CPAP withdrawal]
Apnoea-hypopnoea-index (AHI) [Change from baseline in AHI after 2 weeks of CPAP withdrawal]
Oxygen Desaturation Index (ODI) [Change from baseline in ODI after 2 weeks of CPAP withdrawal]

Eligibility Criteria

Criteria

Ages Eligible for Study:

20 Years to 75 Years

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

Inclusion Criteria:

Objectively confirmed OSA (at the time of original diagnosis) with an oxygen desaturation index (ODI) and apnoea-hypopnoea-index (AHI) of ≥20/h.
Currently an oxygen desaturation index (≥4% dips) of ≥15/h during an ambulatory nocturnal pulse oximetry performed on the last night of a four-night period off CPAP.
Treated with CPAP for more than 12 months
Device usage >4h per night, >80% of the last 365 days, and AHI<10 with treatment (according to CPAP machine download data).
Age between 20 and 75 years.
Written informed consent as documented by signature.

Exclusion Criteria:

Previous ischemic or haemorrhagic stroke; known cerebral aneurysm or arterio-venous malformation.
Carotid artery stenosis > 70%
Use of alpha- and beta-adrenergic blocking medication, antianginal medications, triptans, selective COX-inhibitors
Unstable, untreated coronary or peripheral artery disease, severe arterial hypertension or hypotension (>180/110 or <90/60mmHg)
Implanted pacemaker or internal cardiac defibrillator
Changes in medication during the trial
Previous ventilatory failure (awake SpO2 <93% andPaCO2>6kPa).
Obesity hypoventilation syndrome, COPD
Previously diagnosed with Cheyne-Stokes breathing.
Current professional driver or any previous sleep related driving accidents.
Caffeine or nicotine abuse 12 hours before measurements