title: Obstructive sleep apnea, masked hypertension, and arterial stiffness in men.
abstract: BACKGROUND
  Obstructive sleep apnea (OSA) is an established cause of hypertension. However, it is not clear whether the frequency of masked hypertension in patients with OSA and whether OSA have an independent role on arterial stiffness taking into account ambulatory blood pressure (BP) monitoring (ABPM).
  
  
  METHODS
  We evaluated 61 male normotensive participants as determined by casual clinic BP level <140/90 mm Hg without clinical evidence of cardiovascular disease and on no medications (43 patients with moderate-to-severe OSA (apnea-hypopnea index (AHI) > or = 15 events/hour by polysomnography) and 18 age- and body mass index-matched controls without OSA (AHI <5 events/hour)). Pulse wave velocity (PWV), an index of arterial stiffness, and 24-h ABPM were performed in a blinded fashion. Masked hypertension was defined when abnormal daytime ABPM was > or = 135 or > or = 85 mm Hg.
  
  
  RESULTS
  The AHI and lowest oxygen saturation were 2.6 +/- 1.6 and 90 +/- 2 vs. 52.8 +/- 21.0 events/hour and 75 +/- 10% for controls and OSA patients, respectively; P < 0.001. Compared with controls, patients with OSA had higher office systolic BP (113 +/- 9 vs. 118 +/- 10 mm Hg; P = 0.05) and a higher unadjusted proportion of masked hypertension (2 controls (11.1%) vs. 13 patients (30.2%); P < 0.05). PWV was 8.7 +/- 0.7, 9.4 +/- 1.0, and 10.6 +/- 1.1 m/s in the control, OSA without and with masked hypertension groups, respectively (P < 0.01 for each comparison). Multiple regression showed that systolic daytime ABPM and the lowest oxygen saturation were independently related to PWV (adjusted R2 = 0.34; P < 0.01).
  
  
  CONCLUSIONS
  Patients with OSA presented a higher unadjusted rate of masked hypertension than matched controls. Lowest oxygen saturation has an independent association with arterial stiffness.
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: Luzia
authors.initials: L
authors.lastname: Diegues-Silva
authors.forename: Patrícia M
authors.initials: PM
authors.lastname: Diniz
authors.forename: Luiz A
authors.initials: LA
authors.lastname: Bortolotto
authors.forename: Rodrigo P
authors.initials: RP
authors.lastname: Pedrosa
authors.forename: Roberta B
authors.initials: RB
authors.lastname: Couto
authors.forename: Bianca
authors.initials: B
authors.lastname: Marcondes
authors.forename: Dante M A
authors.initials: DM
authors.lastname: Giorgi
authors.forename: Geraldo
authors.initials: G
authors.lastname: Lorenzi-Filho
authors.forename: Eduardo M
authors.initials: EM
authors.lastname: Krieger
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity; D001794:Blood Pressure; D004548:Elasticity; D006801:Humans; D006973:Hypertension / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology*; D000860:Hypoxia / Q000150:complications*; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011673:Pulsatile Flow; D020181:Sleep Apnea, Obstructive / Q000150:complications* / Q000503:physiopathology*; D014655:Vascular Resistance