Obstructive sleep apnea, masked hypertension, and arterial stiffness in men.
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.
Drager
Luciano F
LF
Hypertension Unit, Heart Institute (InCor), University of São Paulo Medical School, São Paulo, Brazil. luciano.drager@incor.usp.br
Diegues-Silva
Luzia
L
Diniz
Patrícia M
PM
Bortolotto
Luiz A
LA
Pedrosa
Rodrigo P
RP
Couto
Roberta B
RB
Marcondes
Bianca
B
Giorgi
Dante M A
DM
Lorenzi-Filho
Geraldo
G
Krieger
Eduardo M
EM
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