title: Case control study of cerebrovascular damage defined by magnetic resonance imaging in patients with OSA and normal matched control subjects.
abstract: OBJECTIVE
  To assess whether MRI detectable evidence of silent cerebrovascular disease is more prevalent in patients with obstructive sleep apnea (OSA) when compared to carefully matched control subjects.
  
  
  METHODS
  Case-control study of patients with OSA attending a specialist sleep clinic and matched control subjects drawn from the normal community.
  
  
  METHODS
  Forty-five sleep clinic patients with moderate to severe OSA and excessive daytime sleepiness, matched to 45 control subjects without excessive sleepiness or evidence of OSA on a sleep study. Matched variables included age, body mass index (BMI), alcohol and cigarette consumption, treated hypertension, and ischaemic heart disease.
  
  
  METHODS
  N/A.
  
  
  RESULTS
  All subjects underwent 24-hour ambulatory blood pressure recordings (before treatment in OSA patients) and sagittal T1, axial T2, and coronal dual echo cerebral MRI imaging to detect clinically silent abnormalities related to hypertensive cerebrovascular disease; areas of high signal foci in deep white matter (DWM), lacunae, and periventricular hyperintensity. Lacunae/high signal foci in DWM and/or periventricular hyperintensity were present in 15 (33%) OSA subjects and 16 (35%) controls, despite significant increases in mean daytime diastolic blood pressure (4.6mmHg, p<0.05), and both nighttime diastolic (7.2mmHg, p<0.001) and systolic blood pressures (9.2mmHg, p<0.05) in OSA subjects. These data exclude more than a 17% excess prevalence of MRI detected minor cerebrovascular disease in the OSA patients, with 95% confidence.
  
  
  CONCLUSIONS
  Sub-clinical cerebrovascular disease is prevalent in both clinic patients with OSA and their matched control subjects. Despite the increased arterial blood pressures, there is, however, no apparent excess of MRI-evident subclinical cerebrovascular disease in patients with OSA compared to appropriately matched control subjects.
authors.affiliation: Department of Respiratory Medicine, Royal Berkshire Hospital, Reading, UK. cwhdavies@doctors.org.uk
authors.forename: C W
authors.initials: CW
authors.lastname: Davies
authors.forename: J H
authors.initials: JH
authors.lastname: Crosby
authors.forename: R L
authors.initials: RL
authors.lastname: Mullins
authors.forename: Z C
authors.initials: ZC
authors.lastname: Traill
authors.forename: P
authors.initials: P
authors.lastname: Anslow
authors.forename: R J
authors.initials: RJ
authors.lastname: Davies
authors.forename: J R
authors.initials: JR
authors.lastname: Stradling
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018660:Blood Pressure Monitoring, Ambulatory; D015992:Body Mass Index; D001921:Brain / Q000473:pathology*; D002561:Cerebrovascular Disorders / Q000175:diagnosis*; D002940:Circadian Rhythm; D003937:Diagnosis, Differential; D006970:Disorders of Excessive Somnolence / Q000175:diagnosis / Q000209:etiology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D020181:Sleep Apnea, Obstructive / Q000150:complications / Q000175:diagnosis*