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11 February 2012
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| [ Print-friendly version ] |
| Effect of continuous positive airway pressure (CPAP) therapy on arterial stiffness in patients with obstructive sleep apnoea/hypopnoea syndrome (OSAHS) |
| ISRCTN | ISRCTN48783995 |
| ClinicalTrials.gov identifier | |
| Public title | Effect of continuous positive airway pressure (CPAP) therapy on arterial stiffness in patients with obstructive sleep apnoea/hypopnoea syndrome (OSAHS) |
| 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 |
| Acronym | N/A |
| Serial number at source | PG/06/092/21267 |
| 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. |
| Lay summary | |
| Ethics approval | Lothian Local Research Ethics Committee 02 approved on the 24th January 2007 (ref: 06/S1102/54) |
| Study design | Randomised double blind placebo-controlled crossover trial |
| Countries of recruitment | United Kingdom |
| Disease/condition/study domain | Obstructive sleep apnoea/hypopnoea syndrome (OSAHS) |
| Participants - inclusion criteria |
Both:
1. Males and females aged 18 - 65 years Patients: 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 |
| Participants - 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 |
| Anticipated start date | 01/02/2007 |
| Anticipated end date | 04/08/2009 |
| Status of trial | Completed |
| Patient information material | Not available in web format, please use the contact details below to request a patient information sheet |
| Target number of participants | 80 (including 60 patients with varying severity of disease and 20 controls) |
| Interventions |
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. |
| Primary outcome measure(s) | Arterial stiffness as measured by PWV/PWA and aortic distensibility as measured by cardiovascular MRI, at timepoints 0, 12 and 24 weeks |
| Secondary outcome measure(s) |
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 |
| Sources of funding | British Heart Foundation (BHF) (UK) (ref: PG/06/092/21267) |
| Trial website | |
| Publications | |
| Contact name | Dr Renata Riha |
| Address |
Department of Sleep Medicine
Royal Infirmary of Edinburgh 51 Little France Crescent |
| City/town | Edinburgh |
| Zip/Postcode | EH16 4SA |
| Country | United Kingdom |
| Sponsor | University of Edinburgh (UK) |
| Address |
Queen's Medical Research Institute
47 Little France Crescent |
| City/town | Edinburgh |
| Zip/Postcode | EH16 4TJ |
| Country | United Kingdom |
| Sponsor website: | http://www.ed.ac.uk |
| Date applied | 07/07/2010 |
| Last edited | 27/07/2010 |
| Date ISRCTN assigned | 27/07/2010 |
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