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Cerebrovascular Reactivity in Obstructive Sleep Apnea (OSA) Subjects

16. december 2014 opdateret af: University Health Network, Toronto

Spatial and Temporal Response of Cerebrovascular Response in OSA

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.

Studieoversigt

Status

Ukendt

Betingelser

Detaljeret beskrivelse

OSA is associated with increased risk of cardiovascular and cerebrovascular disease compared to the general population. The mechanism for the increased stroke risk in OSA is unknown. However, the constellation of adverse pathophysiological consequences, including intermittent hypoxia and carbon-dioxide retention as a result of OSA may be detrimental to CVR and predispose the brain to ischemia. Previous studies in OSA subjects have measured CVR only using TCD. Therefore, our study will examine CVR by two methods (TCD and BOLD-MRI) with reliable and reproducible hypercapnia and independent control of oxygen saturation (RespiractTM). Patterns seen on CVR may eventually allow the identification of OSA patients who will be at greatest risk for stroke and will therefore, require aggressive risk reduction and/or treatment irrespective of symptoms.

Undersøgelsestype

Observationel

Tilmelding (Forventet)

60

Kontakter og lokationer

Dette afsnit indeholder kontaktoplysninger for dem, der udfører undersøgelsen, og oplysninger om, hvor denne undersøgelse udføres.

Studiesteder

    • Ontario
      • Toronto, Ontario, Canada, M5G 2N2
        • Rekruttering
        • Toronto Gneral Hospital
        • Ledende efterforsker:
          • Clodagh Ryan, MD
        • Underforsker:
          • J Fisher, MD
        • Underforsker:
          • J Duffin, PhD
        • Underforsker:
          • D Mikulis, MD
        • Underforsker:
          • a Battisti, BSc
        • Underforsker:
          • O Pucci, BSc

Deltagelseskriterier

Forskere leder efter personer, der passer til en bestemt beskrivelse, kaldet berettigelseskriterier. Nogle eksempler på disse kriterier er en persons generelle helbredstilstand eller tidligere behandlinger.

Berettigelseskriterier

Aldre berettiget til at studere

18 år til 80 år (Voksen, Ældre voksen)

Tager imod sunde frivillige

Ingen

Køn, der er berettiget til at studere

Alle

Prøveudtagningsmetode

Ikke-sandsynlighedsprøve

Studiebefolkning

Community Population

Beskrivelse

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.

Studieplan

Dette afsnit indeholder detaljer om studieplanen, herunder hvordan undersøgelsen er designet, og hvad undersøgelsen måler.

Hvordan er undersøgelsen tilrettelagt?

Design detaljer

  • Observationsmodeller: Kohorte
  • Tidsperspektiver: Fremadrettet

Kohorter og interventioner

Gruppe / kohorte
Control without Sleep Apnea
Subjects with Sleep Apnea

Hvad måler undersøgelsen?

Primære resultatmål

Resultatmål
Tidsramme
Document the diurnal differences in global CVR as measured by TCD, between those with and without OSA
Tidsramme: Between 8pm and 7am approximately
Between 8pm and 7am approximately

Sekundære resultatmål

Resultatmål
Tidsramme
Use BOLD MRI to quantify global and regional CVR in various regions and vascular territories of the brain in subjects with OSA.
Tidsramme: one week
one week

Samarbejdspartnere og efterforskere

Det er her, du vil finde personer og organisationer, der er involveret i denne undersøgelse.

Efterforskere

  • Ledende efterforsker: Clodagh M Ryan, Toronto General Hospital

Datoer for undersøgelser

Disse datoer sporer fremskridtene for indsendelser af undersøgelsesrekord og resumeresultater til ClinicalTrials.gov. Studieregistreringer og rapporterede resultater gennemgås af National Library of Medicine (NLM) for at sikre, at de opfylder specifikke kvalitetskontrolstandarder, før de offentliggøres på den offentlige hjemmeside.

Studer store datoer

Studiestart

1. februar 2010

Primær færdiggørelse (Forventet)

1. februar 2015

Studieafslutning (Forventet)

1. april 2015

Datoer for studieregistrering

Først indsendt

20. maj 2010

Først indsendt, der opfyldte QC-kriterier

28. maj 2010

Først opslået (Skøn)

31. maj 2010

Opdateringer af undersøgelsesjournaler

Sidste opdatering sendt (Skøn)

18. december 2014

Sidste opdatering indsendt, der opfyldte kvalitetskontrolkriterier

16. december 2014

Sidst verificeret

1. oktober 2010

Mere information

Disse oplysninger blev hentet direkte fra webstedet clinicaltrials.gov uden ændringer. Hvis du har nogen anmodninger om at ændre, fjerne eller opdatere dine undersøgelsesoplysninger, bedes du kontakte register@clinicaltrials.gov. Så snart en ændring er implementeret på clinicaltrials.gov, vil denne også blive opdateret automatisk på vores hjemmeside .

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