Peripheral Vascular Function in Obstructive Sleep Apnoea

Completed

• Conditions: Obstructive Sleep Apnoea; Obesity

• Registration Number: NCT01619748
• Lead Sponsor: Sheffield Teaching Hospitals NHS Foundation Trust

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.

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 Timeline

• Study Start: 2012-06
• Study First Submitted: 2012-06-08
• Study First Submitted QC: 2012-06-12
• Study First Posted: 2012-06-14
• Primary Completion: 2013-04
• Study Completion: 2013-06
• Status Verified: 2013-08
• Last Update Submitted: 2013-08-06
• Last Update Posted: 2013-08-07

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 45

Inclusion Criteria

• Obstructive sleep apnoea diagnosed using overnight polysomnography
• Age 18-90 years

Exclusion Criteria

• Unable to perform the tests involved in the study
• Unable to provide written informed consent

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
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

Name	Time	Method
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.

Trial Locations

Locations (2)

Centre for Sport and Exercise Science, Sheffield Hallam University; 🇬🇧 Sheffield, South Yorkshire, United Kingdom

Sheffield Teaching Hospitals NHS FT; 🇬🇧 Sheffield, South Yorkshire, United Kingdom