Echocardiographic findings in children with obstructive sleep apnea: A systematic review

Prevalence of pulmonary hypertension in children with obstructive sleep apnea living at high altitude

Introduction

The prevalence of obstructive sleep apnea (OSA) is 1-4 %. Some reports describe its association with pulmonary hypertension (PH), but its prevalence is unknown. No studies at high altitude have determined the relationship between OSA and PH. The aim of this study was to establish the prevalence of PH in children diagnosed with OSA living in a high-altitude city at 2640 m above sea level.

Methods

Children between 2 and 16 years of age referred to the Sleep Laboratory of the Fundación Neumológica Colombiana in Bogotá with a positive polysomnogram for OSA were included, and a two-dimensional transthoracic echocardiogram (TTE) was performed to evaluate PH. Statistical analysis was performed using median, interquartile range, chi-squared test, and Kruskall-Wallis test.

Results

Of the 55 patients (n: 55), 63.6 % were male, with a median age of 6 years, 14 children (25.5 %) were overweight; 12 children (21.8 %) had mild OSA, 12 (21.8 %) had moderate OSA and 31 (56.4 %) severe OSA. In patients with severe OSA, the minimum saturation during events was 78 % with a desaturation index (DI) of 33.8/hour (p < 0.01). T90 and T85 increased proportionally with OSA severity (p < 0.05). Of the 55 patients with OSA, none had PH according to echocardiography; 4 patients (7.2 %) had pulmonary artery systolic pressure (PASP) at the upper limit of normal (ULN), and it was not related to a higher body mass index (BMI).

Conclusions

We found no association between OSA and PH in children with OSA at high altitude.

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.

Prevalence of pulmonary hypertension in obstructive sleep apnea and its relation to disease severity

STUDY OBJECTIVES

The purpose of this study is to examine the prevalence of pulmonary hypertension (PHTN) in children with obstructive sleep apnea (OSA) using echocardiographic (ECHO) parameters and to examine ECHO findings as they relate to severity of OSA.

METHODS

A retrospective cohort study of patients with OSA undergoing polysomnogram and ECHO within 30 days of each other, between January 1, 2015, and December 31, 2020, was performed, excluding cardiac disease. ECHO evidence of PHTN was defined as ≥ 2 of the following: tricuspid regurgitation velocity > 3.0 m/s, pulmonary acceleration/ejection time ratio < 0.3, left ventricular eccentricity index > 1.5, and right ventricular dysfunction or abnormal geometry. ECHO parameters were compared to OSA severity using obstructive apnea-hypopnea index, percent of time with oxygen saturation < 90%, and percent of time with end-tidal carbon dioxide > 50 mmHg. Odds ratios were calculated for each comorbidity to evaluate for risk factors.

RESULTS

Of 509 patients, 4.3% were found to have echocardiographic evidence of PHTN. Neither obstructive apnea-hypopnea index severity nor worsening hypoxemia or hypercarbia correlated with worsening ECHO parameters. Comorbidities including bronchopulmonary dysplasia (odds ratio, 5.22, 2.01-13.53), prematurity (odds ratio, 3.10, 1.28-7.47), and autism (odds ratio, 3.69, 1.01-13.49) were associated with increased odds of PHTN.

CONCLUSIONS

Significant echocardiographic evidence of PHTN was seen in 4.3% of children with OSA. ECHO findings of PHTN did not correlate with polysomnogram parameters. Comorbidities, particularly bronchopulmonary dysplasia, prematurity, and autism, appear to be a risk factor for developing PHTN in patients with OSA.

CITATION

Milligan I, Shaw AK, Leu R, Kanaan U, Michelfelder E. Prevalence of pulmonary hypertension in obstructive sleep apnea and its relation to disease severity. J Clin Sleep Med. 2024;20(5):675-680.

Is there an OAHI or O2 nadir that predicts the need for preoperative echocardiogram prior to adenotonsillectomy for children with severe obstructive sleep apnea?

PURPOSE

To investigate threshold values for obstructive apnea-hypopnea index (OAHI) and nadir oxygen saturation (NspO2) in children with severe obstructive sleep apnea (OSA) to identify children most appropriate for preoperative echocardiography.

METHODS

A multi-institutional retrospective chart review was performed on children who underwent echocardiography and polysomnogram within a year. Children with severe OSA as defined by OAHI > 10 or NspO2 < 80% were included. Receiver operator curves and Youden's J index were used to assess the discriminatory ability and threshold values of OAHI and NspO2 for right heart strain (RHS) on echocardiography.

RESULTS

A total of 173 prepubertal (< 10 years) children and 71 postpubertal (≥ 10 years) children of age were included. RHS was seen in 9 (5%) prepubertal children and 4 (6%) postpubertal children. In prepubertal children, OAHI and NspO2 were poor predictors of RHS (area under the curve [AUC] 0.53 [95%CI 0.45-0.61], p = 0.748; AUC 0.56 [95%CI 0.48-0.64], p = 0.609). In postpubertal children, threshold values of 55 events/hour and 69% were strong predictors for RHS (AUC 0.88 [95%CI 0.78-0.95], p < 0.001; AUC 0.92 [95%CI 0.83-0.97], p < 0.001).

CONCLUSION

In children with severe OSA, evidence of RHS is low. Postpubertal children with OAHI > 55 and NspO2 < 69% appear most appropriate for echocardiography. Clinicians should weigh the risks and benefits of preoperative echocardiography for each child with these threshold values in mind.

Role of automated functional imaging and myocardial work in assessment of cardiac function in children with obstructive sleep apnea

BACKGROUND

Early identification of abnormal left ventricular function in children with obstructive sleep apnea (OSA) is difficult using conventional echocardiographic indices and commonly used clinical markers of myocardial damage. We sought to investigate the value of automatic function imaging and myocardial work parameters in predicting early cardiac impairment in children having OSA with preserved left heart function and thereby identifying an optimal index for assessment.

PATIENTS AND METHODS

Fifty-two children who presented with symptoms of nocturnal sleep snoring and open-mouth breathing and 34 healthy controls were enrolled in this study. Clinical characteristics and conventional echocardiographic data were collected, and image analysis was performed using two-dimensional speckle-tracking echocardiography to obtain left ventricular global longitudinal strain (GLS), post-systolic index, peak strain dispersion, global work index (GWI), global constructive work (GCW), global wasted work, and global work efficiency.

RESULTS

Children with OSA had significantly lower GLS, GWI, and GCW than those without (P < 0.05). Additionally, GWI (β = -32.87, 95% CI: -53.47 to -12.27), and GCW (β = -35.09, 95% CI: -55.35 to -14.84) were found to correlate with the disease severity in the multiple linear regression mode, with worsening values observed as the severity of the disease increased. ROC curve analysis revealed that GCW was the best predictor of myocardial dysfunction, with an AUC of 0.809 (P < 0.001), and the best cutoff point for diagnosing myocardial damage in children with OSA was 1965.5 mmHg%, with a sensitivity of 92.5% and a specificity of 58.7%.

CONCLUSIONS

GLS, GWI, and GCW were identified as predictors of myocardial dysfunction in children with OSA, with GCW being the best predictor.

New Approaches to the Management of Cardiovascular Risk Associated with Sleep Respiratory Disorders in Pediatric Patients

Exposure to risk factors in youth can exacerbate the development of future cardiovascular disease (CVD). Obstructive sleep apnea (OSA), characterized by repetitive episodes of airway obstructions, could trigger said CVD acting as a modifiable risk factor. Measurements from echocardiography have shown impairments in the anatomy and function of the heart related to the severity of OSA. Therefore, the aim of this review was to propose a new clinical approach to the management of cardiovascular risk (CVR) in children based on treating OSA. The review includes studies assessing echocardiographic parameters for cardiac function and structure in pediatric OSA diagnosed using the apnea-hypopnea index (AHI) ≥ 1/h using polysomnography (PSG) and conducted within a year. Based on the reviewed evidence, in addition to PSG, echocardiography should be considered in OSA children in order to indicate the need for treatment and to reduce their future CVR. A follow-up echocardiography after treatment could be performed if impairments in the anatomy and function were found. Prioritizing parameters intimately connected to comorbidity could propel more effective patient-centered care. In conclusion, a reevaluation of pediatric OSA strategies should be considered, emphasizing comorbidity-related parameters in the cardiovascular field. Further studies are needed to assess this approach, potentially leading to enhanced protocols for more effective pediatric OSA treatment and CVR prevention.

Effects of chronic intermittent hypoxia on left cardiac function in young and aged mice

Obstructive sleep apnea (OSA) is an independent risk factor for cardiovascular disease that is characterized by chronic intermittent hypoxia (CIH), and its impact is related to age. This study aims to assess the age-related impact of CIH on cardiac function and to further explore the mechanism. After 8 weeks of severe CIH exposure, the hearts of young mice showed slight physiological hypertrophy, decreased diastolic function, and collagen I accumulation but no obvious change in contractile function. However, the contractile function of the hearts of aged mice was severely decreased. CIH exposure promoted the fragmentation of mitochondria in the hearts of aged mice and decreased the mitochondrial membrane potential of cardiomyocytes, but these effects were not observed in young mice exposed to the same conditions. CIH induced significant decreases in basal respiration, maximum respiration and ATP production in cardiac mitochondria of aged mice compared to those of young mice. The assessment of mitochondrial-related proteins showed that young mouse hearts had upregulated adaptive nuclear respiratory factors (Nrf)1/2 sirtuin (SIRT)1/3 and transcription factor A (TFAM) expression that stabilized mitochondrial function in response to CIH exposure. Aged mouse hearts exhibited maladaptation to CIH exposure, and downregulation of SIRT1 and TFAM expression resulted in mitochondrial dysfunction.

Tissue Doppler echocardiography in children with OSA before and after tonsillectomy and adenoidectomy: A systematic review and meta-analysis

BACKGROUND

When to order an echocardiogram in children with obstructive sleep apnea (OSA) is debated. Studies evaluating the utility of pre-operative standard echocardiography are inconsistent. Tissue Doppler imaging (TDI) is an additional technique that quantifies the velocity of myocardial motion to assess cardiac function. The utility of TDI in pediatric OSA remains unclear.

METHODS

A systematic review and meta-analysis were performed in accordance with PRISMA guidelines using PubMed, Scopus, CINAHL, and Cochrane Library databases. Studies of echocardiographic findings using TDI in children with polysomnogram confirmed OSA before and after tonsillectomy and adenoidectomy (T&A) were included. 1,423 studies were screened, and 4 studies met inclusion criteria. Meta-analysis of echocardiographic findings was performed.

RESULTS

Data from 560 children were analyzed. Study groups included pre- and post-T&A children with OSA and non OSA controls. Pre-T&A S' wave at the tricuspid annulus (S' RV) was decreased with a mean difference of -1.04 [95% CI -1.57, -0.52, p < 0.001] and E'/A' ratio at the mitral annulus (E'/A' LV) was decreased with a mean difference of -0.74 [95% CI -0.85, -0.64, p < 0.001] when compared to controls. These variables were not statistically different when comparing post-T&A to controls.

CONCLUSIONS

TDI appears to successfully detect subclinical changes in cardiac function in children with OSA. However, echocardiography parameters of post-T&A and non OSA control children were similar. Further prospective studies stratified by OSA severity are needed with both TDI and standard echocardiography to define the utility of pre-operative cardiac imaging.