Long-term changes in blood pressure control in elementary school-aged children with sleep-disordered breathing

In adults sleep-disordered breathing (SDB) has been associated with impaired baroreflex control of blood pressure (BP), which has been linked to increased cardiovascular morbidity. In children, the long-term effects of SDB on baroreflex sensitivity (BRS) and BP variability (BPV) are unknown.

Children previously diagnosed with SDB (n=40) and 20 nonsnoring controls aged 11-16 y underwent overnight polysomnography with continuous BP measurement, four years after the original diagnosis. At follow-up, SDB was categorized as resolved (absence of snoring and obstructive apnea hypopnea index (OAHI)≤1) or unresolved (continued to snore or had an OAHI>1). BRS and BPV were calculated using cross-spectral analysis and power spectral analysis, respectively.

Only children with resolved obstructive sleep apnea (OSA) at follow-up demonstrated an increase in BRS from 9.7±3 (ms mmHg(-1)) at baseline to 11.8±4 (ms mmHg(-1)) at follow-up (P=.03). However, children with all severities of both resolved and unresolved SDB showed a significant decrease in BPV from baseline to follow-up (a decrease in total power BPV (P<.05) and a shift in BPV spectra away from respiratory-related frequencies (increased low-frequency/high-frequency [LF/HF] ratio, P<.01). The change in OAHI was the sole determinant of change in BRS, HF power, and LF/HF ratio.

Improvement in SDB was associated with improved BP control, regardless if SDB was treated or spontaneously resolved four years after initial diagnosis. Our findings highlight the importance of monitoring children to ensure improvement of SDB and reduce the risk for cardiovascular morbidity in the future.