Cerebrovascular Reactivity in Obstructive Sleep Apnea (OSA) Subjects
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ClinicalTrials.gov Identifier: NCT01133717 |
Recruitment Status
: Unknown
Verified October 2010 by University Health Network, Toronto.
Recruitment status was: Recruiting
First Posted
: May 31, 2010
Last Update Posted
: December 18, 2014
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Obstructive sleep apnea (OSA) is a prevalent sleep breathing disorder in the general population in which recurrent collapse of the upper airway occurs during sleep. OSA is more prevalent in subjects with stroke and is associated with a 3 fold increased risk of stroke. This makes it a serious public health problem. Approximately 50% of subjects with OSA are asymptomatic and are often only detected following investigation for the cause of heart disease or a stroke. In subjects who are treated for OSA many are intolerant or poorly compliant with treatment. Therefore, the identification of those subjects with OSA most at risk of adverse consequences such as stroke is important, so that treatment compliance can be improved.
Therfore, the investigators want to determine if compared to subjects without OSA, subjects with OSA have evidence of increased stroke risk by assessment of changes in cerebral blood flow (cerebrovascular reactivity) as measured on Doppler ultrasound of the middle cerebral artery (TCD) and blood oxygen level-dependent magnetic resonance imaging of patterns of cerebral blood flow (BOLD MRI) to two stimuli. These stimuli include increased carbon dioxide concentrations (causes increased cerebral blood flow) and reduced oxygen concentrations (causing decreased cerebral blood flow). In order to deliver these stimuli the investigators will use a special machine (RespiractTM) which allows for the precise control of carbon dioxide and oxygen concentrations in the lungs and blood. The precise control of carbon dioxide and oxygen in conjunction with BOLD MRI has enabled the production of detailed maps of the brain that identify areas of healthy and abnormal blood supply.
Condition or disease |
---|
Sleep Apnea |
Study Type : | Observational |
Estimated Enrollment : | 60 participants |
Observational Model: | Cohort |
Time Perspective: | Prospective |
Official Title: | Spatial and Temporal Response of Cerebrovascular Response in OSA |
Study Start Date : | February 2010 |
Estimated Primary Completion Date : | February 2015 |
Estimated Study Completion Date : | April 2015 |

Group/Cohort |
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Control without Sleep Apnea |
Subjects with Sleep Apnea |
- Document the diurnal differences in global CVR as measured by TCD, between those with and without OSA [ Time Frame: Between 8pm and 7am approximately ]
- Use BOLD MRI to quantify global and regional CVR in various regions and vascular territories of the brain in subjects with OSA. [ Time Frame: one week ]

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Ages Eligible for Study: | 18 Years to 80 Years (Adult, Senior) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | Yes |
Sampling Method: | Non-Probability Sample |
Inclusion Criteria:
- Subjects referred for sleep studies
Exclusion Criteria:
- Known cardiac, neurological or major liver or kidney disease -
- Cardioverter/defibrillator metal heart valve or pacemaker
- Vascular stent implanted within 6 weeks
- Severe claustrophobia
- Pregnancy
- Shrapnel or history of ophthalmic foreign body
- Resting oxygen saturation on room air < 95%
- Insulin-dependent diabetes
- Obstructive or restrictive lung disease such that subject is unable to walk up 2 flights of stairs
- Major depression.

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT01133717
Contact: Clodagh M Ryan, MD | 4163404719 | clodagh.ryan@uhn.on.ca | |
Contact: Ann battisti, BSc | abattist@uhnres.utoronto.ca |
Canada, Ontario | |
Toronto Gneral Hospital | Recruiting |
Toronto, Ontario, Canada, M5G 2N2 | |
Principal Investigator: Clodagh Ryan, MD | |
Sub-Investigator: J Fisher, MD | |
Sub-Investigator: J Duffin, PhD | |
Sub-Investigator: D Mikulis, MD | |
Sub-Investigator: a Battisti, BSc | |
Sub-Investigator: O Pucci, BSc |
Principal Investigator: | Clodagh M Ryan | Toronto General Hospital |
Responsible Party: | University Health Network, Toronto |
ClinicalTrials.gov Identifier: | NCT01133717 History of Changes |
Other Study ID Numbers: |
09-0831-BE |
First Posted: | May 31, 2010 Key Record Dates |
Last Update Posted: | December 18, 2014 |
Last Verified: | October 2010 |
Keywords provided by University Health Network, Toronto:
Sleep Apnea Cerebrovascular Reactivity |
Additional relevant MeSH terms:
Apnea Sleep Apnea Syndromes Respiration Disorders Respiratory Tract Diseases Signs and Symptoms, Respiratory |
Signs and Symptoms Sleep Disorders, Intrinsic Dyssomnias Sleep Wake Disorders Nervous System Diseases |