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

Objective/Background: 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. Patients/Methods: 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. Results: 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 SpO(2) nadir (r=-0.61, p = 0.002). Participants with OSAS had a high pediatric Epworth score [median interquartile range (IQR) = 8(4,9)1,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). Conclusions: 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. (C) 2015 Elsevier B.V. All rights reserved.