Baroreflex gain in children with obstructive sleep apnea.
BACKGROUND
We previously demonstrated that children with obstructive sleep apnea have increased blood pressure associated with changes in left ventricular mass index. Others have shown in adults that blood pressure variability is an important predictor of changes in left ventricular mass. The baroreflex system buffers blood pressure changes by varying heart rate. We have thus hypothesized that (1) baroreflex system gain is increased during sleep, improving blood pressure buffering; (2) children with obstructive sleep apnea lack this baroreflex gain increase; and (3) reduced blood pressure buffering results in exaggerated blood pressure variability that is associated with end-organ damage.


OBJECTIVE
Compare measures of left ventricular mass index and nighttime baroreflex gain of healthy children to those of children with obstructive sleep apnea.


METHODS
A total of 169 children (50 control subjects, 63 with mild obstructive sleep apnea, and 56 with severe obstructive sleep apnea) with a mean age of 9.9 years (+/-2.2) underwent echocardiography followed by polysomnography with continuous blood pressure measurement. Baroreflex gain was calculated in time and frequency domains.


RESULTS
Healthy children demonstrated a nighttime pattern of increasing baroreflex gain. Children with obstructive sleep apnea had decreased nighttime baroreflex gain compared with control subjects. Nighttime blood pressure and blood pressure variability were significantly correlated with left ventricular mass index.


CONCLUSIONS
Obstructive sleep apnea is associated with a decrease in nighttime baroreflex gain and an increase in blood pressure variability. This increase is correlated with changes in left ventricular mass index.
McConnell
Keith
K
Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.
Somers
Virend K
VK
Kimball
Thomas
T
Daniels
Stephen
S
VanDyke
Rhonda
R
Fenchel
Matthew
M
Cohen
Aliza
A
Willging
Paul
P
Shamsuzzaman
Abu
A
Amin
Raouf
R
D017704:Baroreflex / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology*; D016022:Case-Control Studies; D002648:Child; D004452:Echocardiography; D005260:Female; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000209:etiology; D008297:Male; D017286:Polysomnography; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology*