title: A prospective cohort study of the long-term effects of CPAP on carotid artery intima-media thickness in obstructive sleep apnea syndrome.
abstract: OBJECTIVE
  To examine the long-term effect of CPAP on carotid artery intima-media thickness (IMT) in patients with Obstructive sleep apnea syndrome(OSAS).
  
  
  METHODS
  A prospective observational study over 12 months at a teaching hospital on 50 patients newly diagnosed with OSAS who received CPAP or conservative treatment (CT). Carotid IMT was assessed with B-mode Doppler ultrasound from both carotid arteries using images of the far wall of the distal 10 mm of the common carotid arteries at baseline, 6 months and 12 months. MEASUREMENTS AND RESULTS [MEAN (SE)]: Altogether 28 and 22 patients received CPAP and CT respectively without significant differences in age 48.8(1.8) vs 50.5(2.0)yrs, BMI 28.2(0.7) vs 28.0(1.2)kg/m2, ESS 13.1(0.7) vs 12.7(0.6), AHI 38(3) vs 39(3)/hr, arousal index 29(2) vs 29(2)/hr, minimum SaO2 75(2) vs 77(2)% and existing co-morbidities. CPAP usage was 4.6(0.3) and 4.7(0.4)hrs/night over 6 months and 1 year respectively. Carotid artery IMT at baseline, 6 months, and 12 months were 758(30), 721(20), and 705(20)micron for the CPAP group versus 760(30), 770(30), and 778(30)micron respectively for the CT group, p = 0.002. Among those free of cardiovascular disease(n = 24), the carotid artery IMT at baseline, 6 months and 12 months were 722(40), 691(40), and 659(30)micron for the CPAP group (n = 12) with usage 4.5(0.7) and 4.7(0.7) hrs/night over 6 months and 12 months whereas the IMT data for the CT group(n = 12) were 660(20), 685(10), and 690(20)micron respectively, p = 0.006.
  
  
  CONCLUSIONS
  Reduction of carotid artery IMT occurred mostly in the first 6 months and was sustained at 12 months in patients with reasonable CPAP compliance.
authors.affiliation: SH Ho Sleep Apnea Management Center, Department of Medicine & Therapeutics, The Chinese University of Hong Kong, Prince of Wales Hospital, 30-32 Ngan Shing St., Shatin, New Territories, Hong Kong, China. dschui@cuhk.edu.hk
authors.forename: David S
authors.initials: DS
authors.lastname: Hui
authors.forename: Qing
authors.initials: Q
authors.lastname: Shang
authors.forename: Fanny W
authors.initials: FW
authors.lastname: Ko
authors.forename: Susanna S
authors.initials: SS
authors.lastname: Ng
authors.forename: Cheuk-Chun
authors.initials: CC
authors.lastname: Szeto
authors.forename: Jenny
authors.initials: J
authors.lastname: Ngai
authors.forename: Alvin H
authors.initials: AH
authors.lastname: Tung
authors.forename: Kin-Wang
authors.initials: KW
authors.lastname: To
authors.forename: Tat-On
authors.initials: TO
authors.lastname: Chan
authors.forename: Cheuk-Man
authors.initials: CM
authors.lastname: Yu
mesh_terms: D000428:Alcohol Drinking / Q000517:prevention & control; D002339:Carotid Arteries / Q000000981:diagnostic imaging*; D059168:Carotid Intima-Media Thickness; D015331:Cohort Studies; D045422:Continuous Positive Airway Pressure; D005081:Exercise Therapy; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D010349:Patient Compliance; D011446:Prospective Studies; D020181:Sleep Apnea, Obstructive / Q000000981:diagnostic imaging* / Q000628:therapy*; D012892:Sleep Deprivation / Q000517:prevention & control; D013997:Time Factors; D015431:Weight Loss