Effects of short-term CPAP withdrawal on cerebral vascular reactivity measured by BOLD MRI in OSA: a randomised controlled trial
- Sira Thiel1,*,
- Franziska Lettau1,*,
- Protazy Rejmer1,
- Cristina Rossi2,
- Sarah R. Haile3,
- Esther I. Schwarz1,
- Anna S. Stöberl1,
- Noriane A. Sievi1,
- Andreas Boss3,
- Anton S. Becker3,
- Sebastian Winklhofer5,
- John R. Stradling4 and
- Malcolm Kohler1,6
- 1Department of Pulmonology and Sleep Disorders Centre, University Hospital Zurich, Zurich, Switzerland
- 2Department of Diagnostic and Interventional Radiology, University Hospital Zurich, Zurich, Switzerland
- 3Department of Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Switzerland
- 4National Institute for Health Research (NIHR) Oxford Biomedical Research Centre, Oxford University Hospitals NHS Foundation Trust and University of Oxford, United Kingdom
- 5Department of Neuroradiology, University Hospital Zurich, Zurich, Switzerland
- 6Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
- *Contributed equally
- Prof Malcolm Kohler, Chair Respiratory Medicine, Clinical Director, Division of Pulmonology and Sleep Disorders Centre, University Hospital of Zurich, Raemistrasse 100, Zurich, Switzerland. E-mail: malcolm.kohler{at}usz.ch
Abstract
Introduction: 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.
Methods: 41 OSA patients (88% male, mean age 57±10 yrs.) were randomised to subtherapeutic, or continuation of therapeutic, CPAP. At baseline, and after two 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.
Results: OSA did recur in the subtherapeutic-CPAP group (mean treatment effect apnoea-hypopnoea-index [95%CI] +38.0 [+24.2/+52.0] events·h−1, 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 [95%CI] +9.37 [+1.36 to 17.39] mmHg, p=0.023), there was no significant effect of CPAP withdrawal on CVR assessed via BOLD MRI under either, hyperoxic or hypercapnic conditions.
Conclusion: Short-term CPAP withdrawal did not result in statistically significant different changes of CVR assessed by functional MRI despite recurrence of OSA. We thus conclude that unlike peripheral endothelial function, CVR is not affected by short- term CPAP withdrawal.
Footnotes
This manuscript has recently been accepted for publication in the European Respiratory Journal. It is published here in its accepted form prior to copyediting and typesetting by our production team. After these production processes are complete and the authors have approved the resulting proofs, the article will move to the latest issue of the ERJ online. Please open or download the PDF to view this article.
Conflict of interest: Dr. Thiel has nothing to disclose.
Conflict of interest: Dr. Lettau has nothing to disclose.
Conflict of interest: Dr. Rejmer has nothing to disclose.
Conflict of interest: Dr. Rossi has nothing to disclose.
Conflict of interest: Dr. Haile has nothing to disclose.
Conflict of interest: Dr. Schwarz has nothing to disclose.
Conflict of interest: Dr. Stöberl has nothing to disclose.
Conflict of interest: Dr. Sievi has nothing to disclose.
Conflict of interest: Dr. Boss has nothing to disclose.
Conflict of interest: Dr. Becker has nothing to disclose.
Conflict of interest: Dr. Winklhofer has nothing to disclose.
Conflict of interest: Dr. Stradling reports personal fees from Resmed UK, personal fees from Bayer Germany, outside the submitted work.
Conflict of interest: Dr. Kohler reports grants from University of Zurich, grants from Lunge Zurich, grants from Swiss National Science Foundation, during the conduct of the study; grants from Bayer AG, outside the submitted work.
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