title: Effects of continuous positive airway pressure on early signs of atherosclerosis in obstructive sleep apnea.
abstract: BACKGROUND
  Obstructive sleep apnea (OSA) is associated with adverse cardiovascular outcomes, including myocardial infarction and stroke. Atherosclerosis is a key mechanism for these cardiovascular events. Recent cross-sectional studies showed the presence of early signs of atherosclerosis in patients with OSA who were free of comorbidities.
  
  
  OBJECTIVE
  To determine the impact of treatment with continuous positive airway pressure (CPAP) on atherosclerosis.
  
  
  METHODS
  We randomly assigned 24 patients with severe OSA (age, 46 +/- 6 yr) who were free of comorbidities to receive no treatment (control, n = 12) or CPAP (n = 12) for 4 months. Carotid intima-media thickness, arterial stiffness (evaluated by pulse-wave velocity), carotid diameter, 24-hour blood pressure monitoring, C-reactive protein, and catecholamines were determined at baseline and after 4 months.
  
  
  RESULTS
  At baseline, all measurements were similar in both groups and did not change in the control group after 4 months. In contrast, a significant decrease occurred in carotid intima-media thickness (707 +/- 105 vs. 645 +/- 95 microm, P = 0.04), pulse-wave velocity (10.4 +/- 1.0 vs. 9.3 +/- 0.9 m/s, P < 0.001), C-reactive protein (3.7 +/- 1.8 vs. 2.0 +/- 1.2 mg/L, P = 0.001), and catecholamines (365 +/- 125 vs. 205 +/- 51 ng/ml, P < 0.001) after 4 months of CPAP. Carotid diameter did not change significantly. Regarding the whole group, changes in carotid intima-media thickness were correlated with changes in catecholamines (r = 0.41, P < 0.05). Changes in pulse-wave velocity were correlated with changes in C-reactive protein (r = 0.58, P < 0.01) and catecholamines (r = 0.54, P < 0.01).
  
  
  CONCLUSIONS
  The treatment of OSA significantly improves early signs of atherosclerosis, supporting the concept that OSA is an independent risk factor for atherosclerosis. Clinical trial registered with www.clinicaltrials.gov (NCT 00400543).
authors.affiliation: Hypertension Unit, Heart Institute (InCor), University of São Paulo Medical School, São Paulo, Brazil. luciano.drager@incor.usp.br
authors.forename: Luciano F
authors.initials: LF
authors.lastname: Drager
authors.forename: Luiz A
authors.initials: LA
authors.lastname: Bortolotto
authors.forename: Adelaide C
authors.initials: AC
authors.lastname: Figueiredo
authors.forename: Eduardo M
authors.initials: EM
authors.lastname: Krieger
authors.forename: Geraldo Filho
authors.initials: GF
authors.lastname: Lorenzi
mesh_terms: D000328:Adult; D050197:Atherosclerosis / Q000175:diagnosis* / Q000209:etiology; D018660:Blood Pressure Monitoring, Ambulatory; D002097:C-Reactive Protein / Q000032:analysis; D017536:Carotid Artery, Common / Q000473:pathology; D045422:Continuous Positive Airway Pressure; D006801:Humans; D008297:Male; D008875:Middle Aged; D020181:Sleep Apnea, Obstructive / Q000150:complications / Q000628:therapy*; D017539:Tunica Intima / Q000473:pathology; D017540:Tunica Media / Q000473:pathology
chemical_list: D002097:C-Reactive Protein