Peripheral Vascular Function in Obstructive Sleep Apnoea
Study Details
Study Description
Brief Summary
Peripheral vascular function is impaired in people with obstructive sleep apnoea who are untreated compared with age-, weight- and sex-matched healthy controls.
| Condition or Disease | Intervention/Treatment | Phase |
|---|---|---|
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Detailed Description
Obstructive sleep apnoea (OSA) is a chronic respiratory disorder associated with endothelial dysfunction, increased sympathetic activation and increased cardiovascular risk. The standard treatment paradigm is continuous positive airway pressure (CPAP), however, patient adherence to CPAP is variable. It is unclear to what extent that poor adherence to CPAP therapy augments vascular endothelial function and reduces cardiovascular risk compared to excellent adherence. The main aim of this research is to investigate vascular endothelial function in OSA patients who are poorly-adherent to CPAP therapy. Nitric oxide (NO)-mediated, endothelium-dependent macrovascular and microvascular function (by brachial artery flow-mediated dilatation and forearm cutaneous thermal hyperaemia, respectively) and generalised microvascular function (by post-occlusion reactive hyperaemia) will be assessed in three obese OSA patient populations (high-adherence (n=20); low adherence (n=20); and, untreated (n=20)) and age-/BMI-matched OSA-free controls. We will also assess body composition, cardiovascular risk, lipid status and functional capacity. This research will evaluate treatment efficacy in patients who are poorly-adherent to CPAP treatment and could identify whether an alternative approach to their care should be explored.
Study Design
Arms and Interventions
| Arm | Intervention/Treatment |
|---|---|
| Untreated OSA patients Patients with obstructive sleep apnoea who are untreated |
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| OSA patients highly compliant with CPAP OSA patients established on CPAP therapy (high compliance, > 80% nightly use for ≥ 4 h per night) |
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| OSA patients poorly compliant with CPAP OSA patients established on CPAP therapy (poor compliance, 10% < nightly use < 50% or < 4 h per night) |
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| Age and BMI-matched controls Age and BMI-matched controls without OSA |
Outcome Measures
Primary Outcome Measures
- Flow-mediated dilatation of the brachial artery [Baseline only]
The brachial artery dilator response to a 5-min period of forearm arterial occlusion will be measured using a vascular ultrasound scanner and a 7-MHz linear array probe.
Secondary Outcome Measures
- GTN-mediated dilatation of the brachial artery [Baseline only]
The brachial artery vasodilator response to a 400 microgram sublingual dose of glyceryl trinitrate will be measured using vascular ultrasound imaging.
- Forearm skin blood flow response to 5-min proximal-cuff arterial occlusion [Baseline only]
Proximal arterial occlusion will be performed by inflating a blood pressure cuff placed on the upper arm to 200 mmHg for 5 min. After cuff deflation, the skin blood flow response will be measured using laser Doppler flowmetry.
- Forearm skin blood flow response to localised heating at 42 degrees C [Baseline only]
A local heating unit on the forearm will be heated from 33 to 42 degrees C at a rate of 1 degree C every 10 s. Temperature will be held at 42 degrees C for 35 min. The increase in skin blood flow will be measured using a laser Doppler flowmetry probe placed in the centre of the local heating unit.
Eligibility Criteria
Criteria
Inclusion Criteria:
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Obstructive sleep apnoea diagnosed using overnight polysomnography
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Age 18-90 years
Exclusion Criteria:
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Unable to perform the tests involved in the study
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Unable to provide written informed consent
Contacts and Locations
Locations
| Site | City | State | Country | Postal Code | |
|---|---|---|---|---|---|
| 1 | Centre for Sport and Exercise Science, Sheffield Hallam University | Sheffield | South Yorkshire | United Kingdom | S102BP |
| 2 | Sheffield Teaching Hospitals NHS FT | Sheffield | South Yorkshire | United Kingdom |
Sponsors and Collaborators
- Sheffield Teaching Hospitals NHS Foundation Trust
- Sheffield Hallam University
Investigators
- Study Director: Garry A Tew, PhD, Sheffield Hallam University
- Principal Investigator: James Moss, BSc, Sheffield Hallam University
- Study Director: Stephen Bianchi, MD, Sheffield Teaching Hospitals NHS FT
Study Documents (Full-Text)
None provided.More Information
Publications
None provided.- STH-16309