title: Predictors of impaired endothelial function in obstructive sleep apnea syndrome.
abstract: OBJECTIVE
  Obstructive sleep apnea syndrome (OSA) is associated with increased cardiovascular morbidity and mortality. Endothelial dysfunction (ED), accelerated atherosclerosis and autonomic dysfunction might be the key players responsible for development of vascular diseases in patients with OSA. In a population with suspected OSA and low burden of cardiovascular risk factors, we therefore aimed to investigate the association between potential cardiovascular risk factors including OSA-specific indices, ED and autonomic activity.
  
  
  METHODS
  ED was investigated using reperfusion hyperaemia index (RHI). OSA was assessed using standard polysomnography, autonomic activity was assessed using baroreflex sensitivity (BRS).
  
  
  RESULTS
  We enrolled 31 patients (42.1±11.7 years) with OSA. Significant inverse correlation was found between RHI and apnea-hypopnea index (AHI) (r=-0.550, p=0.001) and between RHI desaturation index (r=-0.533, p=0.002). Positive correlation was found between RHI and minimal nocturnal oxygen saturation (r=0.394, p=0.028). In a multiple regression model AHI was the only significant variable to predict RHI (β=-0.522, p=0.003). We found no correlation between RHI and BRS. RHI in the population with severe OSA (AHI above 30) was significantly lower than RHI in the rest of the population (p=0.012).
  
  
  CONCLUSIONS
  AHI was the only significant independent predictor of impaired endothelial function as expressed by RHI. RHI showed no association with BRS in patients with OSA.
authors.affiliation: 1st Department of Neurology, Faculty of Medicine, Comenius University, Bratislava, Slovakia.
authors.forename: Pavel
authors.initials: P
authors.lastname: Siarnik
authors.affiliation: 1st Department of Neurology, Faculty of Medicine, Comenius University, Bratislava, Slovakia.
authors.forename: Zuzana
authors.initials: Z
authors.lastname: Carnicka
authors.affiliation: 1st Department of Neurology, Faculty of Medicine, Comenius University, Bratislava, Slovakia.
authors.forename: Lucia
authors.initials: L
authors.lastname: Krizova
authors.affiliation: 1st Department of Neurology, Faculty of Medicine, Comenius University, Bratislava, Slovakia.
authors.forename: Helena
authors.initials: H
authors.lastname: Wagnerova
authors.affiliation: 1st Department of Neurology, Faculty of Medicine, Comenius University, Bratislava, Slovakia.
authors.forename: Stanislav
authors.initials: S
authors.lastname: Sutovsky
authors.affiliation: 1st Department of Neurology, Faculty of Medicine, Comenius University, Bratislava, Slovakia.
authors.forename: Katarina
authors.initials: K
authors.lastname: Klobucnikova
authors.affiliation: 1st Department of Neurology, Faculty of Medicine, Comenius University, Bratislava, Slovakia.
authors.forename: Branislav
authors.initials: B
authors.lastname: Kollar
authors.affiliation: 1st Department of Neurology, Faculty of Medicine, Comenius University, Bratislava, Slovakia.
authors.forename: Peter
authors.initials: P
authors.lastname: Turcani
authors.affiliation: Department of Neurology, University of Heidelberg, Heidelberg, Germany.
authors.forename: Marek
authors.initials: M
authors.lastname: Sykora
mesh_terms: D000328:Adult; D017704:Baroreflex / Q000502:physiology; D002318:Cardiovascular Diseases / Q000175:diagnosis* / Q000209:etiology* / Q000503:physiopathology; D004730:Endothelium, Vascular / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D011379:Prognosis; D012307:Risk Factors; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology*