Relationship of Circadian Blood Pressure Dysregulation With Left Ventricular Structure and Function in Children With Obstructive Sleep Apnea.

Obstructive sleep apnea (OSA) in children alters circadian blood pressure (BP) rhythms. We hypothesised that circadian BP dysregulation in paediatric OSA is associated with structural and functional cardiac changes. This was a single-centre, cross-sectional, observational study of children 5-14 years with OSA and healthy controls. Participants underwent polysomnography, 24-h ambulatory BP monitoring, and echocardiography. Circadian BP parameters included times arrived at BP and BP velocity peaks and nadirs, and nocturnal BP dipping. Regression and mediation analyses assessed the relationship between circadian BP parameters and cardiac structure and function. There were 100 children with OSA and 94 controls enrolled with mean ± SD obstructive apnea hypopnea index (OAHI) of 8.2 ± 9.0 and 0.3 ± 0.3 respectively. Earlier diastolic BP and BP velocity peaks were associated with decreased left ventricular relaxation (e' velocity) and increased left atrial pressure (E/e' ratio). Diastolic nocturnal dipping was greater in controls than in the OSA group. Lower nocturnal dipping was also associated with decreased left ventricular relaxation and increased left atrial pressure. Systolic BP dipping was negatively associated with isovolumetric relaxation time. OAHI was a significant covariate in many models. Diastolic nocturnal dipping was a significant mediator in the associations between OAHI and left ventricular relaxation. Circadian BP parameters were not significantly associated with pulmonary artery pressure or cardiac geometry. Shifts in circadian BP parameters and reduced BP dipping were associated with diastolic dysfunction in children; OSA severity influenced many associations highlighting the relevance of OSA severity to cardiac function. Trial Registration: ClinicalTrials.gov identifier: NCT00059111, NCT01837459.