Cardiovascular complications of sleep disordered breathing in the population with Down syndrome

Background: Individuals with Down syndrome (DS), or trisomy 21, are at high risk of developing sleep disordered breathing (SDB) secondary to anatomic, metabolic, endocrinologic, and neurologic reasons. SDB can contribute to the development of cardiovascular disease in the general population; however, a thorough understanding of the relationship between SDB and cardiovascular disease in the population with DS is lacking. Aim of review: The aim of this review is to evaluate the available scientific literature describing cardiovascular complications of sleep disordered breathing in the population with DS. Key scientific concepts of review: Individuals with DS are at high risk of developing sleep disordered breathing. This may contribute to the earlier onset of cardiovascular disease including arrhythmias, cardiac dysfunction, reduced heart rate variability, and pulmonary hypertension. It seems apparent that there is a disruption in the normal homeostatic neurohormonal response to apnea events during sleep in the population with DS, with a notably reduced catecholamine surge during apnea events. This reduced response appears to manifest with a lack of neurophysiologic stimulation to arouse the individual with an associated softened increase in heart rate. These dampened responses may allow for more prolonged hypoxia. Curiously, while this may reduce the incidence of developing systemic hypertension, it may increase the risk of acquiring pulmonary hypertension. Despite these findings, much remains unknown about the impact of sleep disordered breathing on the cardiovascular system in individuals with Down syndrome.