Original ArticleCardiac systolic function in Greek children with obstructive sleep-disordered breathing
Introduction
Accumulating evidence indicates that severity of obstructive sleep-disordered breathing (SDB) in childhood correlates with surrogate measures of future cardiovascular morbidity [1], [2], [3], [4], [5], [6], [7], [8], [9], [10]. Elevated serum concentrations of C-reactive protein (CRP) have been demonstrated in subgroups of children with sleep apnea [2], [11], and increased fasting insulin levels have been found mostly in obese children with SDB [12], [13], [14]. Moreover, a significant association has been identified between the metabolic syndrome and sleep apnea in children and adolescents [3], [9]. Treatment of intermittent upper airway obstruction during sleep with adenotonsillectomy is accompanied by improved lipid profile and endothelial function and reduced CRP levels [1], [4].
In addition, several studies have revealed that obstructive SDB is associated with blood pressure elevation [5], [10], [15] and changes in myocardial structure and function [7], [8], [16], [17]. Children with snoring and apnea-hypopnea index > 5 episodes/h have significantly higher wake systolic and wake and sleep diastolic blood pressure compared to healthy controls [5], and successful treatment of upper airway obstruction by adenotonsillectomy seems to decrease mainly the diastolic component of blood pressure [2], [6], [18]. Subjects with severe sleep apnea can present with pulmonary hypertension [19] and decreased right ventricle systolic function [16], [17]. A recent echocardiography study has identified increased right ventricle end-diastolic dimension and left ventricle mass index [7]. Finally, a negative correlation has been reported between severity of obstructive SDB and left ventricle (LV) diastolic function [8], which improves after surgical removal of adenoids and tonsils [20].
In contrast to older reports [16], [17], recent echocardiography studies have not detected a negative impact of sleep apnea on systolic myocardial function [8], [20]. Children with obstructive SDB, however, have increased blood and urine norepinephrine levels [21], [22], and, at least in adults with sleep apnea, increased release of catecholamines has been associated with decreased sensitivity of β-adrenergic receptors [23]. Desensitization of the β-adrenergic receptors may conceivably lead to isolated reduced systolic function even without the presence of diastolic dysfunction or cardiac structure abnormalities. Therefore, we performed an exploratory study to assess cardiac systolic function in children with moderate-to-severe SDB in comparison to subjects with mild SDB or with primary snoring.
Section snippets
Participants
The study protocol was approved by the University of Thessaly Ethics Committee. Informed consent was obtained from parents of participants and child’s assent from subjects older than 6 years. Consecutive children with snoring (>3 nights/week) who were referred to the Sleep Disorders Laboratory for polysomnography were offered the chance to participate in the study if they did not have (1) symptoms of upper respiratory tract infection; (2) history of cardiovascular, neuromuscular or genetic
Subjects’ characteristics and polysomnography findings
A total of 48 children who had polysomnography at the sleep lab were recruited to the study and underwent echocardiography (age range of 2.3–12.2 years). Two of them were excluded due to patent ductus arteriosus that was diagnosed during echocardiography. Thus, data collected from 46 subjects (22 female; 47.8%) with a mean age of 6.4 ± 2.6 years were analyzed. Their characteristics and polysomnography findings are summarized in Table 1.
Primary outcome measures: indices of systolic ventricular function
The three study groups were similar regarding right ventricle
Discussion
The main finding of the current investigation is the lower LV systolic function in children with moderate-to-severe SDB compared to subjects with primary snoring. This result is in agreement with older pediatric reports that have identified an increase of the right and left ventricle EF after adenotonsillectomy for obstructive sleep apnea [16], [17]. Although the size of the current cohort is modest, the findings add to the scarce literature on the topic and could be utilized in future
Conflict of interest
None of the authors has any conflicts of interest to disclose.
Acknowledgement
Funded by the University of Thessaly Research Committee.
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Left ventricular dysfunction in pediatric sleep apnea
2023, Progress in Pediatric CardiologyEchocardiographic findings in children with obstructive sleep apnea: A systematic review
2021, International Journal of Pediatric OtorhinolaryngologyThe effects of adenotonsillar hypertrophy corrective surgery on left ventricular functions and pulmonary artery pressure in children
2017, International Journal of Pediatric OtorhinolaryngologyCitation Excerpt :In a study of Görür et al. on children with ATH, LVedD and IVSD values were reported to be significantly higher in preoperative group [32]. In another study in children with moderate-severe OSAS, left ventricular ejection fraction and LVFS were determined to be lower compared with patients having mild OSAS or primary snoring and the authors defined a negative correlation between LV systolic functions and the degree of UAO [33]. In our study we did not determine a significant difference between groups regarding LVpWD, LVedD, LVesD or LVFS.
A systematic review and meta-analysis of cohort studies of echocardiographic findings in OSA children after adenotonsilectomy
2014, International Journal of Pediatric OtorhinolaryngologyCitation Excerpt :Following assessment of the full articles seven [25–31] met all the inclusion criteria and methodological requirements. The detailed characteristics of the excluded studies [32–75] are described in Table 2. All the included studies were classified as cohort studies [25–31].
Chemoreceptors, baroreceptors, and autonomic deregulation in children with obstructive sleep apnea
2013, Respiratory Physiology and NeurobiologyCitation Excerpt :Subsequently, several groups of investigators have confirmed the presence of systemic blood pressure abnormalities in pediatric OSA, with such changes being more pronounced during NREM sleep and also more likely to occur in the context of repeated arousals (O’Driscoll et al., 2009a,b; Kohyama et al., 2003; Leung et al., 2006; Bixler et al., 2008; Amin et al., 2004). Furthermore, severity-dependent reductions in left ventricular function with decreased diastolic relaxation and systolic contractility have also been clearly identified in pediatric OSA (Amin et al., 2008; Kaditis et al., 2010; Ugur et al., 2008). Again, the contributions of specific autonomic alterations to these vascular changes remain unexplored in children.
Algorithm for the diagnosis and treatment of pediatric OSA: A proposal of two pediatric sleep centers
2012, Sleep MedicineCitation Excerpt :Uncontrolled studies have shown decreased frequency or complete resolution of enuresis after adenotonsillectomy [66,67]. Note: In addition to clinically apparent morbidity, which has been associated with OSA in population-based studies, smaller reports have identified increased risk for maladaptive responses to intermittent upper airway obstruction during sleep, such as increased oxidative stress, sympathetic nervous system activation, endothelial dysfunction, enhanced systemic inflammation, insulin resistance, dyslipidemia, and changes in cardiac structure and function [53,68–77] (Evidence B). It is unknown whether these abnormalities ultimately lead to cardiovascular and central nervous systems morbidity and, hence, they currently have limited value in the management of pediatric OSA.