Peripheral Vascular Function in Obstructive Sleep Apnoea

Effects of Obstructive Sleep Apnoea and Its Treatment on Macrovascular and Microvascular Function

Peripheral vascular function is impaired in people with obstructive sleep apnoea who are untreated compared with age-, weight- and sex-matched healthy controls.

Study Overview

• Status: Completed
• Conditions: Obesity; Obstructive Sleep Apnoea

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 Type: Observational
• Enrollment (Actual): 45

Contacts and Locations

Study Locations

• United Kingdom
  • South Yorkshire
    • Sheffield, South Yorkshire, United Kingdom, S102BP
      • Centre for Sport and Exercise Science, Sheffield Hallam University
    • Sheffield, South Yorkshire, United Kingdom
      • Sheffield Teaching Hospitals NHS FT

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 90 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Patients and controls living in and around Sheffield, UK

Description

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 Plan

How is the study designed?

Number of groups / cohorts

4

Cohorts and Interventions

Group / Cohort
Untreated OSA patients; Patients with obstructive sleep apnoea who are untreated
OSA patients highly compliant with CPAP; OSA patients established on CPAP therapy (high compliance, > 80% nightly use for ≥ 4 h per night)
OSA patients poorly compliant with CPAP; OSA patients established on CPAP therapy (poor compliance, 10% < nightly use < 50% or < 4 h per night)
Age and BMI-matched controls; Age and BMI-matched controls without OSA

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Flow-mediated dilatation of the brachial artery	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.	Baseline only

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
GTN-mediated dilatation of the brachial artery	The brachial artery vasodilator response to a 400 microgram sublingual dose of glyceryl trinitrate will be measured using vascular ultrasound imaging.	Baseline only
Forearm skin blood flow response to 5-min proximal-cuff arterial occlusion	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.	Baseline only
Forearm skin blood flow response to localised heating at 42 degrees C	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.	Baseline only

Collaborators and Investigators

• Sponsor: Sheffield Teaching Hospitals NHS Foundation Trust
• Collaborators: 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 record dates

Study Major Dates

• Study Start: June 1, 2012
• Primary Completion (Actual): April 1, 2013
• Study Completion (Actual): June 1, 2013

Study Registration Dates

• First Submitted: June 8, 2012
• First Submitted That Met QC Criteria: June 12, 2012
• First Posted (Estimate): June 14, 2012

Study Record Updates

• Last Update Posted (Estimate): August 7, 2013
• Last Update Submitted That Met QC Criteria: August 6, 2013
• Last Verified: August 1, 2013

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Nervous System Diseases; Respiratory Tract Diseases; Respiration Disorders; Sleep Disorders, Intrinsic; Dyssomnias; Sleep Wake Disorders; Signs and Symptoms, Respiratory; Sleep Apnea Syndromes; Sleep Apnea, Obstructive; Apnea
• Other Study ID Numbers: STH-16309