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Eur Respir J. 2019 Feb 21;53(2). pii: 1801854. doi: 10.1183/13993003.01854-2018. Print 2019 Feb.

Effects of short-term continuous positive airway pressure withdrawal on cerebral vascular reactivity measured by blood oxygen level-dependent magnetic resonance imaging in obstructive sleep apnoea: a randomised controlled trial.

Author information

1
Dept of Pulmonology and Sleep Disorders Centre, University Hospital Zurich, Zurich, Switzerland.
2
Contributed equally.
3
Dept of Diagnostic and Interventional Radiology, University Hospital Zurich, Zurich, Switzerland.
4
Dept of Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland.
5
Dept of Neuroradiology, University Hospital Zurich, Zurich, Switzerland.
6
National Institute for Health Research (NIHR) Oxford Biomedical Research Centre, Oxford University Hospitals NHS Foundation Trust and University of Oxford, Oxford, UK.
7
Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland.

Abstract

Impaired cerebral vascular reactivity (CVR) increases long-term stroke risk. Obstructive sleep apnoea (OSA) is associated with peripheral vascular dysfunction and vascular events. The aim of this trial was to evaluate the effect of continuous positive airway pressure (CPAP) withdrawal on CVR.41 OSA patients (88% male, mean age 57±10 years) were randomised to either subtherapeutic or continuation of therapeutic CPAP. At baseline and after 2 weeks, patients underwent a sleep study and magnetic resonance imaging (MRI). CVR was estimated by quantifying the blood oxygen level-dependent (BOLD) MRI response to breathing stimuli.OSA did recur in the subtherapeutic CPAP group (mean treatment effect apnoea-hypopnoea index +38.0 events·h-1, 95% CI 24.2-52.0; p<0.001) but remained controlled in the therapeutic group. Although there was a significant increase in blood pressure upon CPAP withdrawal (mean treatment effect +9.37 mmHg, 95% CI 1.36-17.39; p=0.023), there was no significant effect of CPAP withdrawal on CVR assessed via BOLD MRI under either hyperoxic or hypercapnic conditions.Short-term CPAP withdrawal did not result in statistically significant changes in CVR as assessed by functional MRI, despite the recurrence of OSA. We thus conclude that, unlike peripheral endothelial function, CVR is not affected by short-term CPAP withdrawal.

Conflict of interest statement

Conflict of interest: S. Thiel has nothing to disclose. Conflict of interest: F. Lettau has nothing to disclose. Conflict of interest: P. Rejmer has nothing to disclose. Conflict of interest: C. Rossi has nothing to disclose. Conflict of interest: S.R. Haile has nothing to disclose. Conflict of interest: E.I. Schwarz has nothing to disclose. Conflict of interest: A.S. Stöberl has nothing to disclose. Conflict of interest: N.A. Sievi has nothing to disclose. Conflict of interest: A. Boss has nothing to disclose. Conflict of interest: A.S. Becker has nothing to disclose. Conflict of interest: S. Winklhofer has nothing to disclose. Conflict of interest: J.R. Stradling reports personal fees for consultancy from Resmed UK and Bayer Germany, outside the submitted work. Conflict of interest: M. Kohler reports grants from University of Zurich, Lunge Zurich and Swiss National Science Foundation, during the conduct of the study; and grants from Bayer AG, outside the submitted work.

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