Relationship between obstructive sleep apnea cardiac complications and sleepiness in children with Down syndrome

Children with Down syndrome (DS) have a high rate of pulmonary hypertension and sleepiness. They also have a high prevalence of obstructive sleep apnea syndrome (OSAS). We hypothesized that OSAS was associated with cardiovascular dysfunction and sleepiness in children with DS, and that this dysfunction was partly reversible.

A total of 23 children with DS, aged 8-19 years, were evaluated with polysomnography, echocardiography, and measurement of brain natriuretic peptide (BNP). Children having OSAS were randomized to four months of actual or sham continuous positive airway pressure (CPAP) in a double-blinded fashion.

Of the total participants, 20 (87%) had OSAS. On echocardiography, no participant was found to have pulmonary hypertension, and all participants had a BNP <10 pg/mL. The early/tissue Doppler (E/e') of the lateral mitral annulus, a measure of worse left ventricular (LV) diastolic function, correlated with the arousal index (r = 0.42, p = 0.043) and apnea hypopnea index (AHI; r = 0.61, p = 0.002) and inversely with the SpO2 nadir (r = -0.61, p = 0.002). Participants with OSAS had a high pediatric Epworth score [median interquartile range (IQR) = 8(4,9)],correlating with the arousal index (r = 0.49, p = 0.016). At four months, there were no changes in cardiovascular outcomes or sleepiness between those on actual versus sham CPAP. Hours of actual CPAP use was associated with improved E/e' mitral lateral (r = -0.48, p = 0.044), but surprisingly also correlated with LV mass z-score (r = 0.54, p = 0.018).

In children with DS, LV diastolic function correlated with OSAS severity, with improvement with CPAP use. There was a tendency towards increased sleepiness in those with OSAS, which correlated with the arousal index. Larger studies are warranted to confirm these findings.