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  • Reduction in sympathetic tone in patients with obstructive sleep apnoea: is fixed CPAP more effective than APAP? A randomised, parallel trial protocol

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Cardiovascular medicine
Protocol
Reduction in sympathetic tone in patients with obstructive sleep apnoea: is fixed CPAP more effective than APAP? A randomised, parallel trial protocol
  1. Erika Treptow1,
  2. Jean Louis Pepin1,2,
  3. Sebastien Bailly1,
  4. Patrick Levy1,
  5. Cecile Bosc3,
  6. Marie Destors1,2,
  7. Holger Woehrle4,
  8. Renaud Tamisier1,2
  1. 1 HP2, Inserm 1042, Université Grenoble Alpes, Grenoble, France
  2. 2 Laboratoire sommeil, Hôpital Universitaire de Grenoble, Grenoble, France
  3. 3 Centre Santé et Sommeil, Grenoble, France
  4. 4 Lung Center Ulm, Ulm, Germany
  1. Correspondence to Dr Renaud Tamisier; RTamisier{at}chu-grenoble.fr

Abstract

Introduction Obstructive sleep apnoea (OSA) is a prevalent disease associated with cardiovascular events. Hypertension is one of the major intermediary mechanisms leading to long-term cardiovascular adverse events. Intermittent hypoxia and hypercapnia associated with nocturnal respiratory events stimulate chemoreflexes, resulting in sympathetic overactivity and blood pressure (BP) elevation. Continuous positive airway pressure (CPAP) is the primary treatment for OSA and induces a small but significant reduction in BP. The use of auto-adjusting positive airway pressure (APAP) has increased in the last years and studies showed different ranges of BP reduction when comparing both modalities. However, the pathophysiological mechanisms implicated are not fully elucidated. Variations in pressure through the night inherent to APAP may induce persistent respiratory efforts and sleep fragmentation that might impair sympathovagal balance during sleep and result in smaller decreases in BP. Therefore, this double-blind randomised controlled trial aims to compare muscle sympathetic nerve activity (MSNA) assessed by microneurography (reference method for measuring sympathetic activity) after 1 month of APAP versus fixed CPAP in treatment-naive OSA patients. This present manuscript describes the design of our study, no results are presented herein. and is registered under the below reference number.

Methods and analysis Adult subjects with newly diagnosed OSA (Apnoea–Hypopnoea Index >20/hour) will be randomised for treatment with APAP or fixed CPAP. Measurements of sympathetic activity by MSNA, heart rate variability and catecholamines will be obtained at baseline and after 30 days. The primary composite outcome will be the change in sympathetic tone measured by MSNA in bursts/min and bursts/100 heartbeats. Sample size calculation was performed with bilateral assumption. We will use the Student’s t-test to compare changes in sympathetic tone between groups.

Ethics and dissemination The protocol was approved by The French Regional Ethics Committee. The study started in March 2018 with primary completion expected to March 2019. Dissemination plans of the results include presentations at conferences and publication in peer-reviewed journals.

Trial registration number NCT03428516; Pre-results.

  • obstructive sleep apnea
  • hypertension
  • continuous positive airway pressure
  • sleep medicine
  • sympathetic activity

This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.

https://doi.org/10.1136/bmjopen-2018-024253

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    Footnotes

    • Contributors ET participated in the design of the study, wrote the article based on the study protocol, will include patients, collect and analyse data into the protocol. JLP and PL designed the study, wrote the study protocol, critically revised the manuscript and will include patients into the protocol. SB participated in the design of the protocol, established the statistical analysis plan and calculated the sample size. CB revised the manuscript and will include patients into the protocol. MD revised the manuscript and will include patients into the protocol. HW participated in the design of the study and critically revised the manuscript. RT designed the study, wrote the study protocol and article, critically revised the manuscript and will include patients, and collect and analyse data. The submitted manuscript has been approved by all authors.

    • Funding ET is supported by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)—Brazil. This work was supported by unrestricted grant from ResMed, by the foundation Agir pour les maladies chroniques and by the French National Research Agency in the framework of the ‘Investissements d’avenir’ program (ANR-15-IDEX-02).

    • Competing interests RT reports travel grants from Agiradom (a Home Healthcare provider) and research grants from Resmed.

    • Ethics approval The protocol was approved by The French Regional Ethics Committee (Comite de Protection des Personnes Sud Est V No IRB: 0006705 on 19 February 2018).

    • Provenance and peer review Not commissioned; externally peer reviewed.

    • Patient consent for publication Obtained.