Condition category
Nervous System Diseases
Date applied
Date assigned
Last edited
Retrospectively registered
Overall trial status
Recruitment status
No longer recruiting

Plain English Summary

Not provided at time of registration

Trial website

Contact information



Primary contact

Dr Renata Riha


Contact details

Department of Sleep Medicine
Royal Infirmary of Edinburgh
51 Little France Crescent
EH16 4SA
United Kingdom

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

Aortic distensibility in obstructive sleep apnoea/hypopnoea syndrome (OSAHS) using cardiovascular magnetic resonance imaging and and pulse wave analysis: effect of continuous positive airway pressure (CPAP) therapy


Study hypothesis

Obstructive sleep apnoea/hypopnoea syndrome (OSAHS) affects 1 - 4 % of the middle-aged population causing excessive daytime sleepiness. A greater proportion of the population will exhibit sleep disordered breathing, but will not complain of excessive daytime sleepiness. OSAHS is associated with a significantly increased risk of cardiovascular disease and hypertension. The causes of this are likely to be multifactorial and may include repeated oxygen desaturations or factors associated with the excessive daytime sleepiness. Postulated mechanisms for this increased risk include increased arterial stiffness and endothelial dysfunction, which can be measured non-invasively using applanation tonometry (pulse wave velocity and analysis) and cardiovascular magnetic resonance imaging (MRI). Continuous positive airway pressure (CPAP) therapy is an established treatment for OSAHS and is useful in reducing symptoms, it has also been shown to reduce blood pressure in sleepy patients with OSAHS.

This study aims to measure the effect that CPAP therapy has upon arterial stiffness and endothelial function in patients with OSAHS. By studying patients with varying degrees of OSAHS, both in terms of nocturnal oxygen desaturation and levels of daytime sleepiness, but without known cardiovascular disease we hope to further examine the factors that are important in determining arterial stiffness and endothelial dysfunction in these patients.

Ethics approval

Lothian Local Research Ethics Committee 02, 24/01/2007, ref: 06/S1102/54

Study design

Randomised double blind placebo-controlled crossover trial

Primary study design


Secondary study design

Randomised controlled trial

Trial setting


Trial type


Patient information sheet

Not available in web format, please use the contact details below to request a patient information sheet


Obstructive sleep apnoea/hypopnoea syndrome (OSAHS)


Patients meeting the inclusion criteria will be recruited from the Department of Sleep Medicine. This is a randomised controlled crossover trial with 12 weeks in each limb. The active treatment limb consists of CPAP set to provide optimal pressures for treatment and the placebo limb utilises sham CPAP set to provide a sub-optimal pressure. At baseline and after each limb of the study patients will undergo the following measurements:
1. Pulse wave velocity (PWV) and pulse wave analysis (PWA) - before and after administration of GTN and salbutamol
2. Cardiovascular MRI of aorta
3. Blood pressure recording
4. Epworth Sleepiness Score

Control subjects will undergo the above investigations once.

Patients spent approximately 12 weeks in each limb; total duration of treatment is therefore approximately 24 weeks in total for intervention group. Control subjects were assessed once and there was no further follow up after this.

Intervention type



Not Applicable

Drug names

Primary outcome measure

Arterial stiffness as measured by PWV/PWA and aortic distensibility as measured by cardiovascular MRI, at timepoints 0, 12 and 24 weeks

Secondary outcome measures

Measured at timepoints 0, 12 and 24 weeks:
1. Endothelial function as measured by pulse wave analysis (before and after administration of GTN and salbutamol)
2. Blood pressure changes

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Males and females aged 18 - 65 years

2. Apnoea Hypopnoea Index (AHI) greater than or equal to 15 at polysomnography
3. CPAP naive
4. Ability to give written informed consent

Control subjects:
5. AHI less than or equal to 10 at polysomnography
6. Epworth Sleepiness Score (ESS) less than 11
7. Ability to give written informed consent

Participant type


Age group




Target number of participants

80 (including 60 patients with varying severity of disease and 20 controls)

Participant exclusion criteria

1. Inability to give written informed consent
2. Known cardiovascular disease or diabetes
3. History of respiratory failure
4. Medications affecting blood pressure
5. Reported sleepiness when driving or those who drive for a living
6. Claustrophobia precluding magnetic resonance imaging (MRI) scanning
7. Implanted/foreign bodies precluding MRI scanning

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

Department of Sleep Medicine
EH16 4SA
United Kingdom

Sponsor information


University of Edinburgh (UK)

Sponsor details

Queen's Medical Research Institute
47 Little France Crescent
EH16 4TJ
United Kingdom

Sponsor type




Funder type


Funder name

British Heart Foundation (BHF) (UK) (ref: PG/06/092/21267)

Alternative name(s)


Funding Body Type

private sector organisation

Funding Body Subtype



United Kingdom

Results and Publications

Publication and dissemination plan

Not provided at time of registration

Intention to publish date

Participant level data

Not provided at time of registration

Basic results (scientific)

Publication list

2013 results in:
2013 results in:

Publication citations

  1. Results

    Jones A, Vennelle M, Connell M, McKillop G, Newby DE, Douglas NJ, Riha RL, Arterial stiffness and endothelial function in obstructive sleep apnoea/hypopnoea syndrome., Sleep Med., 2013, 14, 5, 428-432, doi: 10.1016/j.sleep.2013.01.001.

  2. Results

    Jones A, Vennelle M, Connell M, McKillop G, Newby DE, Douglas NJ, Riha RL, The effect of continuous positive airway pressure therapy on arterial stiffness and endothelial function in obstructive sleep apnea: a randomized controlled trial in patients without cardiovascular disease., Sleep Med., 2013, 14, 12, 1260-1265, doi: 10.1016/j.sleep.2013.08.786.

Additional files

Editorial Notes