Efficacy of adenotonsillectomy on pediatric obstructive sleep apnea and related outcomes: A narrative review of current evidence

This review summarizes the current evidence in systematic reviews, meta-analysis and randomized controlled trials regarding adenotonsillectomy outcomes in pediatric obstructive sleep apnea (OSA). Adenotonsillectomy is effective in treating OSA in children without co-morbidities, despite postoperative residual OSA remained in roughly half of these children. For children with comorbidities such as Down syndrome, Prader-Willi syndrome, sickle cell disease, or cerebral palsy, adenotonsillectomy is less effective and associated with more postoperative complications than that in children without comorbidities. For other OSA-related outcomes, evidence from meta-analyses and randomized controlled trials confirm adenotonsillectomy results in improvement of subjective OSA-related outcomes (e.g. symptoms, behaviors, and quality of life), but the results in objective OSA-related outcomes (e.g. cardiometabolic parameters or neurocognitive functions) are inconsistent. Future studies should focus on randomized controlled trials comparing objective OSA-related outcomes and the long-term effects of adenotonsillectomy in children with OSA.

Effects of childhood obstructive sleep apnea with and without daytime sleepiness on behaviors and emotions

OBJECTIVE

To investigate the relationship between obstructive sleep apnea (OSA) with and without excessive daytime sleepiness (EDS) and behavioral and emotional outcomes in non-obese prepubertal children.

METHODS

This was a retrospective analysis of children aged 5-11 years who presented to our unit for assessment of their sleep-related complaints. All children underwent polysomnography (PSG). They also completed the Pediatric Daytime Sleepiness Scale (PDSS) and a sleep diary. OSA was diagnosed if the obstructive apnea-hypopnea index (OAHI) was ≥1 event/hour. EDS was defined as PDSS >15. Behavioral and emotional outcomes were assessed using the Child Behavioral Checklist (CBCL).

RESULTS

Data from 391 children (mean age of 8.6 ± 1.7 years; 67 % male) were analyzed. Seventy children did not have OSA or EDS, 137 had OSA, 50 had reported having EDS but without OSA, and 134 children had both OSA and EDS. There were significantly higher CBCL total problems score in the combined group (61 ± 9) compared to the non-OSA/EDS group (54 ± 10), and the OSA-only group (54 ± 10) (p < 0.001). The presence of EDS was significantly associated with higher CBCL T score and higher odds for clinically significant behavioral problems (T score ≥65) after adjusting for age, sex, BMI z-score and average sleep duration (p < 0.001).

CONCLUSION

Excessive daytime sleepiness is an important contributory factor associated with suboptimal behavioral and emotional outcomes in children with OSA.

The association of tonsillar microbiota with biochemical indices based on obesity and tonsillar hypertrophy in children

The correlation between tonsil microbiome and tonsillar hypertrophy has not been well established. Given that oral dysbiosis is related to several metabolic diseases and that tonsillar hypertrophy leads to disordered breathing during sleep and obesity in children, it is necessary to investigate the relationship between the oral microbiome and tonsillar hypertrophy. After 16S rRNA amplicon sequencing of tonsillectomy samples, we evaluated the correlation between the tonsil microbiome and biochemical blood indices in pediatric patients who underwent tonsillectomy. Groups are classified into two categories: based on BMI, and grades 2, 3, and 4 based on tonsil size. Children with obesity and tonsillar hypertrophy have similar microbiome compositions and induce comparable changes in microbiome abundance and composition, confirming the association from a metagenomic perspective. In addition, obesity and tonsillar hypertrophy demonstrated a strong correlation with the Proteobacteria to Firmicutes (P/F) ratio, and among various biochemical indicators, alanine aminotransferase (ALT) levels increase with obesity and tonsillar hypertrophy, indicating a possible association of tonsil microbiome and liver metabolism. These novel findings demonstrate the significance of the tonsil microbiome and suggest the need for tonsil regulation, particularly during childhood.

The First-Line Approach in Children with Obstructive Sleep Apnea Syndrome (OSA)

Obstructive sleep apnea syndrome (OSA) is the main manifestation of sleep-disordered breathing in children. Untreated OSA can lead to a variety of complications and adverse consequences mainly due to intermittent hypoxemia. The pathogenesis of OSA is multifactorial. In children aged 2 years or older, adenoid and/or tonsil hypertrophy are the most common causes of upper airway lumen reduction; obesity becomes a major risk factor in older children and adolescents since the presence of fat in the pharyngeal soft tissue reduces the caliber of the lumen. Treatment includes surgical and non-surgical options. This narrative review summarizes the evidence available on the first-line approach in children with OSA, including clinical indications for medical therapy, its effectiveness, and possible adverse effects. Literature analysis showed that AT is the first-line treatment in most patients with adenotonsillar hypertrophy associated with OSA but medical therapy in children over 2 years old with mild OSA is a valid option. In mild OSA, a 1- to 6-month trial with intranasal steroids (INS) alone or in combination with montelukast with an appropriate follow-up can be considered. Further studies are needed to develop an algorithm that permits the selection of children with OSA who would benefit from alternatives to surgery, to define the optimal bridge therapy before surgery, to evaluate the long-term effects of INS +/- montelukast, and to compare the impact of standardized approaches for weight loss.

Impact of obstructive sleep apnea in cardiovascular risk in the pediatric population: A systematic review

While the association of obstructive sleep apnea (OSA) with an increased cardiovascular risk (CVR) in the adult population is well known, there is insufficient evidence to affirm something similar in the pediatric population. On the other hand, adenotonsillectomy has been shown to be an effective treatment. Our objective was to evaluate the association of sleep respiratory disorders in children with increased CVR and the impact of adenotonsillectomy in the literature. To this aim, a literature search was conducted, between 2002 to the present. After carrying out a systematic review, the following results were provided: thoracic echocardiography after surgery found improvements in terms of cardiac function and structure; blood pressure (BP) measurement, verified a tendency to higher BP values in the OSA pediatric population, which improved after surgery; different biomarkers of CVR, were increased in OSA patients and improved after treatment and finally; some studies found endothelial dysfunction in pediatric OSA, a measurement of vascular system function, was reversible with adenotonsillectomy. Increases in BP parameters, biological markers related to CVR and alterations in cardiac function structure, have been reported in pediatric patients with OSA. At least, some of these parameters would be reversible after adenotonsillectomy, reflecting a possible reduction in CVR.

Effect of surgical intervention for childhood OSA on blood pressure: A randomized controlled study

OBJECTIVE

To investigate the effect of surgical intervention on 24-h ABP in children with OSA. It was hypothesized that blood pressure would improve following adenotonsillectomy.

METHODS

This was a two-centered investigator-blinded randomized controlled trial. Non-obese pre-pubertal children aged 6-11 years with OSA (obstructive apnea-hypopnea index, OAHI >3/h) underwent 24-h ABP monitoring at baseline and 9 months after the randomly assigned intervention, i.e. Early Surgery (ES) or Watchful Waiting (WW). Intention-to-treat analysis was performed.

RESULTS

137 subjects were randomized. Sixty-two (Age: 7.9y ± 1.3, 71% boys) and 47 (Age: 8.5y ± 1.6, 77% boys) participants from the ES and WW groups, respectively completed the study. Changes in ABP parameters were similar in the ES and WW groups (nighttime systolic BP z-scores: +0.03 ± 0.93 vs. -0.06 ± 1.04, p = 0.65; nighttime diastolic BP z-scores: -0.20 ± 0.95 vs. -0.02 ± 1.00, p = 0.35) despite a greater improvement in OSA in the ES group. However, a reduction in nighttime diastolic BP z-score correlated with improvements in OSA severity indexes (r = 0.21-0.22, p < 0.05), and a significant improvement in nighttime diastolic BP z-score [-0.43 ± 1.01, p = 0.027] following surgery was observed in participants with severe preoperative OSA (OAHI ≥10/h). The ES group had a significant increase in body mass index z-score after surgery [+0.27 ± 0.57, p < 0.001], which correlated with the increase in daytime systolic BP z-score (r = 0.2, p < 0.05).

CONCLUSION

Surgical treatment did not lead to significant improvements in ABP in OSA children except in those with more severe disease. The improvement in BP was partially masked by the weight gain following surgery.

CLINICAL TRIAL REGISTRATION

The trial was registered with the Chinese Clinical Trial Registry (http://www.chictr.org.cn.

REGISTRATION NUMBER

ChiCTR-TRC-14004131).

Surfactant protein D concentration in a pediatric population with suspected sleep disorder

Obstructive sleep apnea (OSA) affects between 2% and 4% in children and there is a search for new biomarkers that can be useful both in the diagnosis and in the evolution of the disease. The surfactant protein D (SP-D) is a collection that is part of the innate immune system exerting an anti-inflammatory and antimicrobial effect. Thus, the objective of this study was to evaluate the concentration of SP-D in the suspect OSA pediatric population. A total of 178 children were recruited in this prospective study. Blood samples, sleep parameters, feeding habits, anthropometric, sociodemographic, and family data were collected. Specific biochemical determinations were made, and the plasmatic concentrations of SP-D were measured by enzyme-linked immunosorbent assay. We found no statistical correlation between the SP-D concentration and the apnea-hypopnea index (AHI) from the data. Nevertheless, the changes in SP-D levels could be correlated to a large extent by the arousals that often go along with hypopneas (r = -0.258, p = 0.011 unadjusted; r = -0.258, p = 0.014 adjusted by age and body mass inded [BMI] Z-score). Intermittent hypoxia was correlated with C-reactive protein levels (r = 0.547, p < 0.001 unadjusted; r = 0.542, p < 0.001 adjusted by age and BMI Z-score). Although AHI and SP-D did not appear to correlate, a secondary analysis suggests that sleep fragmentation, which is produced by arousals, may do, and further research is needed to determine the mechanisms by which changes in SP-D occur in OSA.

Impact of Tonsillectomy on Obesity in Pediatric Patients With Sleep-Disordered Breathing

Objective

Both tonsillar hypertrophy and obesity contribute to pediatric sleep-disordered breathing (SDB). Tonsillectomy addresses anatomical obstruction causing SDB; however, it may adversely affect the obesity profile postoperatively. Herein, we investigate posttonsillectomy body mass index (BMI) changes in pediatric patients.

Study Design

Retrospective case series.

Setting

Tertiary, pediatric urban academic center.

Methods

All patients undergoing tonsillectomy from January 1, 2016, to December 31, 2016, were included. Patients’ age, sex, surgical indication, and preoperative BMI were recorded. Postoperative BMI data were collected between March 1, 2016, and December 31, 2017. Statistical analysis was performed using a generalized regression model, using BMI percentile-for-age weight status.

Results

A total of 1153 patients were included (50% female), with age ranging from 2.0 to 19.5 years (mean [SD], 7.6 [4.0]). The majority (87.8%) had tonsillectomy for SDB. Of the cohort, 560 (48.6%) had available follow-up BMI data. The BMI percentile on the day of the surgery had a median of 65.8, and the BMI percentile on follow-up had a median of 76.4. The median time to follow-up was 197 days with a range of 50 to 605 days. Higher postoperative BMI percentile strongly correlated to higher preoperative BMI percentile (P < .001), as well as younger age (P < .001), male sex (P = .0005), and SDB as a surgical indication (P = .003).

Conclusion

We observed a significant increase in BMI percentile following tonsillectomy, which accounted for a significantly higher proportion of the cohort being classified as overweight or obese postoperatively. These findings necessitate greater preoperative counseling, closer follow-up, and adjunctive measures for obesity management in pediatric patients undergoing tonsillectomy.

Effect of adenotonsillectomy on blood pressure in children with obstructive sleep apnea: a meta-analysis

BACKGROUND

While adenotonsillectomy (T&A) is widely recognized as the first-line therapy for pediatric obstructive sleep apnea (OSA), effects of T&A on blood pressure (BP) remain unclear. This meta-analysis evaluates the associations between T&A and BP in children with OSA.

METHODS

The study protocol was registered on PROSPERO (CRD42020154425). Two authors independently searched the PubMed, Medline, EMBASE, and Cochrane databases. The keywords used were "sleep apnea syndromes," "adenotonsillectomy," and "child." A random-effects model was applied to determine office systolic BP (SBP), diastolic BP (DBP), and ambulatory BP changes.

RESULT

Twelve studies with 1193 children were analyzed (mean age: 7.6 y; 54% boys). The apnea-hypopnea index significantly reduced of 9.4 events/h (95% CI, -12.0 to -6.8) after T&A. Office SBP (-0.24 mmHg; 95% CI, -1.64 to 1.16) and DBP (-1.65 mmHg; 95% CI, -3.47 to 0.17) did not decrease significantly after surgery. No significant decreases were observed in 24-h ambulatory BP after T&A. Subgroup analysis showed a significant postoperative decrease in office SBP (-6.23 mmHg; 95% CI, -7.78 to -4.67) and DBP (-7.93 mmHg; 95% CI, -10.37 to -5.48) among children with hypertension but a slight increase in office SBP (2.50 mmHg; 95% CI, 1.14 to 3.86) and DBP (1.98 mmHg; 95% CI, -0.02 to 3.98) in those without (P for heterogeneity < 0.001).

CONCLUSION

This meta-analysis suggests the office and ambulatory BP changes after T&A in children with OSA are trivial. Moreover, children with hypertension experience a significantly greater decrease in office BP than children without hypertension.

Cardiovascular risks of children with primary snoring: A 5-year follow-up study

BACKGROUND AND OBJECTIVE

This study aimed to investigate if childhood primary snoring (PS) was associated with adverse cardiovascular outcomes at 5-year follow-up.

METHODS

This was a prospective matched cohort study. Subjects were recruited from a hospital-based cohort established from years 2006 to 2012 and they were aged 6-18 years at baseline. Each subject with PS was gender, age and BMI z-score matched with a control who had normal sleep study (obstructive apnoea-hypopnoea index [OAHI] < 1/h) and without habitual snoring (<3 nights/week) at baseline. All subjects underwent measurements of flow-mediated dilation (FMD) and carotid intima-media thickness (cIMT) and sleep study at baseline and follow-up visits. Twenty-four hour ambulatory blood pressure (ABP) was also recorded at follow-up.

RESULTS

Fifty-five case-control pairs were recruited and the length of follow-up was 5.1 ± 1.3 years. At follow-up visit, subjects with PS at baseline had significantly lower FMD (-0.34% [-0.59 to -0.10]), greater cIMT (+0.01 mm [+0.001 to +0.013]), higher wake systolic blood pressure (SBP) (+2.6 mm Hg [+0.02 to +5.1]), sleep SBP (+3.0 mm Hg [+0.3 to +5.6]), sleep diastolic blood pressure (+2.2 mm Hg [+0.04 to +4.4]) and sleep mean arterial pressure (+2.2 mm Hg [+0.1 to +4.2]) compared to matched controls in the fully adjusted model for variables including change in OAHI and parental history of cardiovascular diseases.

CONCLUSION

Childhood PS is associated with poorer endothelial function, greater cIMT and higher ABP at 5-year follow-up irrespective of change in obstructive sleep apnoea severity.

Extracellular Vesicles Derived from Intermittent Hypoxia-Treated Red Blood Cells Impair Endothelial Function Through Regulating eNOS Phosphorylation and ET-1 Expression

PURPOSE

Intermittent hypoxia (IH), a main characteristic of obstructive sleep apnea (OSA) syndrome, has been known as a dominant cause of OSA-related endothelial dysfunction and hypertension. However, the underlying mechanism still remains unclear. Extracellular vesicles (EVs), small vesicles secreted by various cells, can be absorbed by endothelial cells and then influence vascular function. The aim of this research is to clarify whether and how EVs shedding from red blood cells (RBCs) are involved in IH-induced endothelial dysfunction.

METHODS

EVs were extracted by ultracentrifugation. After the identification of property and purity, EVs from IH-exposed RBCs (IH REVs) and normoxia-exposed RBCs (NOR REVs) or from OSA and non-OSA patient RBCs were utilized to treat C57BL/6 mouse aortas or human umbilical vein endothelial cells (HUVECs) for mechanistic exploration.

RESULTS

Functional results demonstrated that REVs from OSA patients dramatically impaired endothelium-dependent relaxations (EDRs). Similarly, in vivo and ex vivo studies showed that IH REVs caused significant endothelial dysfunction compared to control group. Further results presented that IH REVs blocked endothelial nitric oxide synthase (eNOS) phosphorylation through inhibiting PI3K/Akt pathway and enhanced endothelin-1 (ET-1) expression through activating Erk1/2 pathway in endothelial cells. Meanwhile, endothelial dysfunction caused by IH REVs was reversed by Akt activator SC79 as well as Erk kinase inhibitor PD98059, suggesting that PI3K/Akt/eNOS and Erk1/2/ET-1 pathways were implicated in IH REV-induced impaired EDRs.

CONCLUSIONS

This study reveals a novel role of REVs in endothelial dysfunction under IH and dissects the relevant mechanism involved in this process, which will help to establish a comprehensive understanding of OSA or IH-related endothelial dysfunction from a new scope.

Childhood OSA is an independent determinant of blood pressure in adulthood: longitudinal follow-up study

BACKGROUND

Current literature supports cross-sectional association between childhood obstructive sleep apnoea (OSA) and elevated blood pressure (BP). However, long-term cardiovascular outcomes in children with OSA remain unexplored.

OBJECTIVE

To evaluate the associations of childhood OSA with BP parameters in a prospective 10 year follow-up study.

METHODS

Participants were recruited from a cohort established for our previous OSA epidemiological study. They were invited to undergo clinical examination, overnight polysomnography and 24-hour ambulatory BP monitoring. Multivariate linear regression was used to assess the associations of baseline childhood OSA with BP outcomes at follow-up. Multivariable log-binomial regression was used with inverse probability weighting to assess the adjusted associations of childhood OSA with hypertension and non-dipping of nocturnal BP in adulthood.

RESULTS

243 participants (59% male) attended the follow-up visit. The mean age was 9.8 (SD ±1.8) and 20.2 (SD ±1.9) years at baseline and follow-up respectively, with a mean follow-up duration of 10.4 (SD ±1.1) years. Childhood moderate-to-severe OSA was associated with higher nocturnal systolic blood pressure (SBP) (difference from normal controls: 6.5 mm Hg, 95% CI 2.9 to 10.1) and reduced nocturnal dipping of SBP (-4.1%, 95% CI -6.3% to 1.8%) at follow-up, adjusted for age, sex, Body Mass Index and height at baseline, regardless of the presence of OSA at follow-up. Childhood moderate-to-severe OSA was also associated with higher risk of hypertension (relative risk (RR) 2.5, 95% CI 1.2 to 5.3) and non-dipping of nocturnal SBP (RR 1.3, 95% CI 1.0 to 1.7) at follow-up.

CONCLUSION

Childhood OSA was found to be an independent risk factor for adverse BP outcomes in adulthood.

The cardiovascular risk in paediatrics: the paradigm of the obstructive sleep apnoea syndrome

BACKGROUND

Obstructive sleep apnoea syndrome (OSAS) describes a spectrum of abnormal breathing patterns during sleep characterised by snoring, increased upper airway resistance and pharyngeal collapsibility, with alteration of normal oxygenation and ventilation. Intermittent desaturations during sleep have multi-organ implications. Adults with OSAS have an increased risk of developing a dysfunctional endothelium that is characterised by greater adherence of inflammatory mediators to endothelial cells and hypercoagulability. There is increasing evidence to show that risk factors for comorbid cardiovascular disease (CVD) can develop during childhood and adolescence and are likely to continue over time. Risk factors for CVD include both modifiable factors and factors that cannot be changed.

MATERIALS AND METHODS

Using the MEDLINE^® electronic database, we reviewed the scientific literature for published studies evaluating the association between sleep-disordered breathing and cardiovascular damage in children.

RESULTS

In this review, we show the role of blood markers in demonstrating the inflammation caused by intermitted oxygen desaturations during sleep in both healthy and obese children. Several instrumental techniques, in addition to serum biomarkers, can be used to assess vascular endothelial damage and its deterioration in the form of a pre-atherosclerotic condition. The confirmation of their role as markers of inflammation and vascular damage is supported by normalisation after resolution or improvement of the sleep-disordered breathing with surgery.

DISCUSSION

Great attention should be given to this condition in infants and children as it will significantly affect their present and future well-being as they grow into adulthood. Healthcare professionals, especially paediatricians, should be trained to recognise the signs and symptoms of the disease in order to send children forward for specialist care in centres dealing with sleep-disordered breathing.

Study of Sleep Disorders among Young Children Using Hindi Translated and Validated Version of Pediatric Sleep Questionnaire

OBJECTIVE

The objective of this study is to assess the prevalence of sleep disorders among children aging between 4 and 9 years using Hindi version of Pediatric Sleep Questionnaire (PSQ).

METHODS

This study had two parts first, translation and validation of PSQ into Hindi language, and second, assessment of the prevalence of sleep disorders using PSQ Hindi version. Hindi PSQ was distributed in randomly chosen primary schools in a semi-urban area. The children were requested to get them filled by their parents. When the questionnaires were returned, responses were analyzed.

RESULTS

Most of the items of the Hindi version had perfect agreement with original questionnaire in a bilingual population (κ =1). Totally, 435 children were included in the field study having average age of 6.3 years. Obstructive sleep apnea was reported in 7.5% children; symptoms suggestive of restless legs syndrome were reported by 2%-3%; teeth grinding by 13.9% and sleep talking by 22.6% children.

CONCLUSION

PSQ Hindi version is a validated tool to screen for sleep disorders among children. Sleep disorders are fairly prevalent among young children in India.

Obstructive sleep apnoea syndrome and endothelial function: potential impact of different treatment strategies-meta-analysis of prospective studies

PURPOSE

Previous studies have shown an association between obstructive sleep apnoea syndrome (OSAS) and cardiovascular events. Whether this association is mediated by an impairment of endothelial function, which is itself a driver of elevated cardiovascular risk, has yet to be clarified, as it is the eventual protective role of several OSAS treatments. The aim of our meta-analysis is to evaluate the effect of various OSAS treatments on endothelial function calculated by means of flow-mediated dilatation (FMD).

METHODS

We conducted a meta-analysis of prospective studies including patients affected by mild to severe OSAS treated with continuous positive airway pressure (CPAP), surgery, oral appliance and medical treatments. FMD was measured before and after treatment RESULTS: After pooling results from different treatment strategies, OSAS treatment showed a positive impact on endothelial function (Mean Difference [MD] = 2.58; 95% CI 1.95-3.20; p < 0.00001).

CONCLUSIONS

Our study supports the hypothesis that several modalities of treatment for OSAS positively impact endothelial function. Whether this effect also associates with an improvement of clinical outcomes remains to be ascertained.

How OSA Evolves From Childhood to Young Adulthood: Natural History From a 10-Year Follow-up Study

BACKGROUND

Understanding the natural history of childhood OSA can help to determine disease prognosis and to guide risk stratification and management strategies.

METHODS

To evaluate the natural history of childhood OSA and factors associated with spontaneous remission and persistent and incident OSA from childhood to late adolescence/early adulthood, a longitudinal analysis of a prospective community-based cohort was designed. Subjects from a cohort established for an OSA prevalence study were invited to participate in this 10-year follow-up study.

RESULTS

Two hundred and forty-three participants (59% male) took part, and their mean age was 9.8 (SD, ± 1.8) and 20.2 (SD, ± 1.9) years at baseline and follow-up, respectively. The mean follow-up duration was 10.4 (SD, ± 1.1) years. Associations between baseline and follow-up log-transformed obstructive apnea-hypopnea index (OAHI) differed by age; a significant positive association was observed only among participants aged 10 years or older at baseline. Overall polysomnographic remission rate (with OAHI < 1 event/h at follow-up) of childhood OSA was 30%, and 69% had an OAHI < 5 events/h at follow-up. Complete remission of OSA was associated with female sex. Incidence of adolescent/adult OSA with an OAHI ≥ 5 events/h at follow-up was 22%. Male sex and higher baseline BMI z score were associated with incident OSA.

CONCLUSIONS

A proportion of children with OSA, particularly female children, had complete resolution during transition to late adolescence or early adulthood. Childhood and adolescent OSA are distinct entities, with the latter more likely to persist into adulthood. Obesity and male sex are consistent key risk factors for incident OSA.

Polysomnographic correlates of endothelial function in children with obstructive sleep apnea

OBJECTIVES

To evaluate endothelial function in a large cohort of children clinically referred for suspected obstructive sleep apnea syndrome (OSAS), and to identify risk factors contributing to the presence of endothelial dysfunction (ED).

METHODS

Habitually snoring children (age range, 3-11 years) were recruited. All participants underwent overnight polysomnography (PSG). Endothelial function test used peripheral arterial tonometry (PAT) to derive the reactive hyperemia index (RHI). Subjects were then divided into mild OSA, moderate-severe OSA and primary snorers (PS), according to their obstructive apnea-hypopnea index (OAHI).

RESULTS

A total of 355 subjects were recruited. There were no differences in age, gender, or BMI z score among the three groups. Both mild and moderate-severe OSA groups had lower RHI than PS (P < 0.001, P = 0.001, respectively). Linear regression analysis revealed that RHI was positively correlated with age (r = 0.17, P = 0.002), BMI z score (r = 0.14, P = 0.008) and oxygen saturation nadir (r = 0.15, P = 0.006), but negatively correlated with oxygen desaturation index (ODI_3%; r = -0.19, P = 0.001) and respiratory-related arousal index (ArI-resp) (r = -0.24, P < 0.001). In stepwise regression analysis, age, BMI z score, and ArI-resp were independently associated with endothelial function (r = 0.34, P < 0.001).

CONCLUSION

Children with OSA are at increased risk for abnormal endothelial function than habitually snoring children. Furthermore, in addition to age and BMI, which are well-established factors affecting endothelial function, both intermittent hypoxia and sleep fragmentation during sleep also emerge as candidate risk factors contributing to endothelial dysfunction in snoring children.

CLINICAL TRIAL

Follow up of PS and OSAHS in Chinese children, https://clinicaltrials.gov/, Clinical number: NCT02447614.

Which place of pharmacological approaches beyond continuous positive airway pressure to treat vascular disease related to obstructive sleep apnea?

Obstructive sleep apnea (OSA) is characterized by recurrent episodes of partial or complete upper airway obstruction, occurring during sleep, leading to chronic intermittent hypoxia (IH), which harms the cardiovascular system. OSA is associated with both functional and structural vascular alterations that contribute to an increased prevalence of fatal and non-fatal cardiovascular events. OSA is a heterogeneous disease with respect to the severity of hypoxia, the presence of daytime symptoms, obesity, and cardiovascular comorbidities. Various clusters of OSA phenotypes have been described leading to more highly personalized treatment. The aim of this review is to describe the various therapeutic strategies including continuous positive airway pressure (CPAP), oral appliances, surgery, weight loss, and especially pharmacological interventions that have been evaluated to reduce vascular alterations in both OSA patients and preclinical animal models. Conventional therapies, predominantly CPAP, have a limited impact on vascular alterations in the presence of co-morbidities. A better knowledge of pharmacological therapies targeting IH-induced vascular alterations will facilitate the use of combined therapies and is crucial for designing clinical trials in well-defined OSA phenotypes.

Longitudinal Cardiovascular Outcomes of Sleep Disordered Breathing in Children: A Meta-Analysis and Systematic Review

Objectives

The presence of sleep disordered breathing (SDB) is known to impact long-term cardiovascular morbidity in adults; however, the long-term effects in children are poorly understood. We aimed to systematically review and synthesize studies published to date on the long-term effects of SDB in children.

Study Design

Meta-analysis and systematic review using PubMed, CINAHL, Embase, and Scopus (all indexed years).

Methods

We searched for English-language articles containing original human data from prospective studies, with ≥7 participants, in children ≤18 years of age. Data regarding study design, demographics, clinical characteristics, outcomes, level of evidence, and risk of bias were obtained. Articles were independently reviewed by three investigators. Retrospective and cross-sectional studies were excluded.

Results

Of 1701 identified abstracts, 25 articles (combined n = 1418) were ultimately included. All studies reported longitudinal outcomes following treatment of SDB, 21 studies exclusively reporting outcomes after adenotonsillectomy. Therefore, studies were combined to objectively assess the effect of SDB treatment on cardiovascular outcomes. Although all cardiovascular parameters were within the normal range at baseline, at follow-up there was a significant decrease in mean pulmonary artery pressure, right ventricular end diastolic diameter, heart rate, mitral Em/Am ratio, and C-reactive protein. There was no significant change in interventricular septum thickness, left ventricular parameters (shortening fraction, systolic and end diastolic diameters, ejection fraction, posterior wall thickness, isovolumetric relaxation time), left atrial diameter, and aortic and pulmonary valve peak velocities.

Conclusions

Studies assessing the long-term cardiovascular effects of SDB in children are limited. The available literature indicates effects on autonomic function, right, and left heart function following treatment for SDB. However, well-designed, large-scale, prospective cohort studies (using standardized outcomes) are needed to better understand the relationship of cardiovascular morbidity in the context of pediatric SDB.

Sleep disordered breathing in childhood

Sleep disordered breathing (SDB) in childhood is linked with significant end-organ dysfunction across various systems, particularly with cardiovascular, neurocognitive and metabolic consequences. If we understand the pathophysiology of SDB, diagnose it promptly and treat appropriately, we may be able to prevent morbidity associated with SDB and also save health resources around the world. In this article, we highlight articles on this topic published in medical journals in the past year.

Prematurity, obesity and adenotonsillar hypertrophy are risk factors for sleep disordered breathinghttp://ow.ly/W47FU

Pediatric OSA Syndrome Morbidity Biomarkers: The Hunt Is Finally On!

Since initial reports 40 years ago on pediatric OSA syndrome (OSAS) as a distinct and prevalent clinical entity, substantial advances have occurred in the delineation of diagnostic and treatment approaches. However, despite emerging and compelling evidence that OSAS increases the risk for cognitive, cardiovascular, and metabolic end-organ morbidities, routine assessment of such morbidities is seldom conducted in clinical practice. One of the major reasons for such discrepancies resides in the relatively labor-intensive and onerous steps that would be required to detect the presence of any of such morbidities, further adding to the already elevated cost of diagnosing the disorder. To circumvent these obstacles, the search for biomarker signatures of pediatric OSA and its cognitive and cardiometabolic consequences was launched, and considerable progress has occurred since then. Here, we review the current evidence for the presence of morbidity-related biomarkers among children with OSAS, and explore future opportunities in this promising arena.

Effects of adenotonsillectomy on plasma inflammatory biomarkers in obese children with obstructive sleep apnea: A community-based study

Background

Obesity and obstructive sleep apnea syndrome (OSA) are highly prevalent and frequently overlapping conditions in children that lead to systemic inflammation, the latter being implicated in the various end-organ morbidities associated with these conditions.

Aim

To examine the effects of adenotonsillectomy (T&A) on plasma levels of inflammatory markers in obese children with polysomnographically diagnosed OSA who were prospectively recruited from the community.

Methods

Obese children prospectively diagnosed with OSA, underwent T&A and a second overnight polysomnogram (PSG) after surgery. Plasma fasting morning samples obtained after each of the 2 PSG were assayed for multiple inflammatory and metabolic markers including interleukin-6 (IL-6), IL-18, plasminogen activator inhibitor-1 (PAI-1), monocyte chemoattractant protein-1 (MCP-1), matrix metalloproteinase- (MMP-9), adiponectin, apelin C, leptin and osteocrin.

Results

Out of 122 potential candidates, 100 obese children with OSA completed the study with only 1/3 exhibiting normalization of their PSG after T&A (i.e., AHI≤1/hrTST). However, overall significant decreases in MCP-1, PAI-1, MMP-9, IL-18 and IL-6, and increases in adropin and osteocrin plasma concentrations occurred after T&A. Several of the T&A responsive biomarkers exhibited excellent sensitivity and moderate specificity to predict residual OSA (i.e., AHI≥/hrTST).

Conclusions

A defined subset of systemic inflammatory and metabolic biomarkers is reversibly altered in the context of OSA among community-based obese children, further reinforcing the concept on the interactive pro-inflammatory effects of sleep disorders such as OSA and obesity contributing to downstream end-organ morbidities.

Endothelial dysfunction and oxidative stress in children with sleep disordered breathing: role of NADPH oxidase

OBJECTIVE

Oxidative stress plays a crucial role in impairing endothelial function in sleep disordered breathing (SDB) but the underlying mechanism is still undefined. The objective of this study was to evaluate the interplay between oxidative stress, assessed by serum isoprostanes (8-iso-PGF2α) and soluble NOX2-dp (sNOX2-dp), and endothelial function, assessed by flow-mediated dilation (FMD), in children with SDB and healthy controls (HC).

METHODS

One-hundred forty-four children including 45 with primary snoring (PS), 22 with obstructive sleep apnea (OSA) and 67 HC were recruited in this study; in 15 out of 22 OSA children FMD, serum 8-iso-PGF2α and sNOX2-dp were assessed before and after one month post adeno-tonsillectomy (AT).

RESULTS

Compared with HC, OSA and PS children had significantly higher sNOX2-dp and serum 8-iso-PGF2α levels and lower FMD; compared with PS, FMD was significantly lower in OSA children. No significant difference for sNOX2-dp and serum 8-iso-PGF2α was observed between OSA and PS children. FMD was inversely correlated with sNOX2-dp levels (p<0.001) and with serum 8-iso-PGF2α (p<0.001). In multiple linear regression analysis, sNOX2-dp (p<0.001) and serum 8-iso-PGF2α (p<0.001) were the only independent predictive variables associated with FMD. AT significantly decreased sNOX2-dp and serum 8-iso-PGF2α levels (from 38.2±8.8 to 22.4±11.1 pg/ml, p<0.001, and from 281.4±69.7 to 226.0±66.4 pg/ml, p<0.001, respectively); conversely, FMD significantly increased after AT in OSA children (from 3.0±1.5 to 8.0±2.8%, p<0.001).

CONCLUSION

This study suggests that NOX2-derived oxidative stress is involved in artery dysfunction in SDB children. Such hypothesis is reinforced by FMD improvement after AT coincidentally with oxidative stress lowering.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT02247167.