The effect of central sleep apnea on sleep architecture in children with obstructive sleep apnea.

OBJECTIVE: This study aimed to investigate how central sleep apnea (CSA) impacts sleep patterns in children with obstructive sleep apnea (OSA). METHODS: Children undergoing polysomnography (PSG) were enrolled and sorted into two groups: those with OSA alone (Group A) and those with both OSA and CSA (CAI <1 nd: children with 10 % CSA or more and less than 50 %, Group B). Statistical analysis was conducted to compare sleep structure and clinical features between Group A and Group B. RESULTS: Group B exhibited significantly higher respiratory events, apnea hypoventilation index, apnea index and oxygen desaturation index (ODI) compared to Group A (p < 0.05). Group B also showed higher total sleep time and arousal index than Group A (P < 0.05). The proportion of time spent in stage N3 was lower in Group B than in Group A (P < 0.05). Moreover, mean heart rate and minimum heart rate were higher in Group B compared to Group A (P < 0.05).Minimum oxygenation levels (including non-rapid eye movement (NREM) stages) were lowe in Group B than in Group A (P < 0.05). Additionally, the prevalence of positional obstructive sleep apnea (P-OSA) was greater in Group B than in Group A (P < 0.05). CONCLUSION: In comparison to those with OSA alone, children with OSA and concurrent CSA exhibited distinct sleep patterns, including reduced N3uration, higher arousal index, longer respiratory events, higher ODI, and lower oxygen saturation, higher heart rate.

A case of middle-aged central sleep apnea due to Joubert syndrome with different treatment effects of oxygen and acetazolamide.

We report a case of severe central sleep apnea incidentally diagnosed during polysomnography for suspected obstructive sleep apnea. Characteristic clinical features included episodic hyperventilation followed by apnea from hypocapnia, which did not follow a Cheyne-Stokes pattern. Combined with the identification of cerebellar and brainstem malformations known as the "molar tooth sign" on a brain magnetic resonance imaging, developmental delay, and motor coordination problems, Joubert syndrome (a congenital disease) was first diagnosed at the age of 50 years. Central apneas were also observed during wakefulness, although not continuously. During sleep, continuous positive airway pressure and adaptive servo-ventilation were ineffective at the referring clinic and at our hospital. Supplemental oxygen decreased the frequency of central apneas and significantly shortened the duration of each central sleep apnea compared with room air. In contrast, the opposite response was observed with acetazolamide administration. CITATION: Murashima R, Shiota S, Sugiyama A, et al. A case of middle-aged central sleep apnea due to Joubert syndrome with different treatment effects of oxygen and acetazolamide. J Clin Sleep Med. 2024;20(10):1705-1710.

Tracheostomy and inpatient outcomes among children with congenital central hypoventilation syndrome: A kids' inpatient database study.

STUDY OBJECTIVES: Congenital central hypoventilation syndrome (CCHS) is a rare disease predisposing children to respiratory failure due to abnormal ventilatory drive. Variability in hypoventilation and respiratory support need have been reported. We aim to identify clinical variables associated with incident tracheostomy and common etiologies of hospitalization among children with CCHS. METHODS: Hospital discharge records were obtained for children (<21 years) with CCHS hospitalized between 2006 and 2019 from the Kid's Inpatient Database. Primary diagnostic categories for hospitalizations with CCHS were summarized. Multivariable logistic regression models were used to explore risk factors associated with incident tracheostomy. RESULTS: Among 2404 hospitalizations with CCHS, 133 (5.5%) had incident tracheostomy, 1230 (51.2%) had established tracheostomy, and 1041 (43.3%) had no tracheostomy. Compared with children without tracheostomy, those with incident tracheostomy were younger, had a history of prematurity, congenital heart disease, laryngeal, glottic, and subglottic stenosis (LGSS), congenital airway anomalies, neuromuscular weakness, gastroesophageal reflux disease. Children without tracheostomy had higher mortality than those with tracheostomy status (2.19% vs. 0.66%). Multivariable-adjusted analyses showed that incident tracheostomy was associated with infancy (0-1 years), neuromuscular weakness, and congenital heart disease. Most common diagnostic categories include (1) diseases of the respiratory system (30.23%), (2) injury and poisoning (9.35%), and (3) diseases of the nervous system and sense organs (6.71%). CONCLUSIONS: Children with CCHS who received incident tracheostomy are more likely to be younger and with LGSS, neuromuscular weakness and congenital heart disease. Clinicians should be aware of these risk factors representing more severe CCHS with earlier manifestation needing tracheostomy. Higher mortality among nontracheostomy group highlights the need for considering tracheostomy in caring for children with CCHS.

Temporal association of ventricular arrhythmias and respiratory events in heart failure patients with central sleep apnoea.

In contrast to obstructive sleep apnoea, the peak of sympathetic tone in central sleep apnoea occurs during the hyperventilation phase. To explore the temporal association of premature ventricular complex (PVC) burden in the context of the apnoea/hypopnoea-hyperpnoea cycle, the duration of apnoea/hypopnoea was defined as 100 %. We assessed the PVC burden throughout the apnoea/hypopnoea-hyperpnoea cycle during the periods of ±150 % in 50 % increments before and after the apnoea/hypopnoea phase. In this subanalysis of 54 SERVE-HF patients, PVC burden was 32 % higher in the late hyperventilation period (50-100 % after apnoea/hypopnoea) compared to the apnoea/hypopnoea phase.

The epidemiological characteristics of sleep disordered breathing in congestive heart failure: A prospective, single centre study in Southeast Asia.

BACKGROUND: The presence of sleep-disordered breathing (SDB) in congestive heart failure (CHF) is associated with poor prognosis and is underdiagnosed despite advances in CHF management. The prevalence of SDB in CHF remains understudied in South East Asia. METHODS: A prospective, observational single-centre study was conducted where 116 consecutive patients in a specialised heart failure clinic underwent level 1, attended polysomnography (PSG). RESULTS: The prevalence of SDB was 78% using the apnoea-hypopnea index (AHI), AHI ⩾ 5/h threshold, and 59% with the AHI ⩾ 15/h threshold. Obstructive sleep apnoea (OSA) was the predominant type of SDB and was associated with increased body mass index and neck circumference. STOP-BANG was predictive of SDB, especially in men. Central sleep apnoea (CSA) patients had worse sleep indexes and lower awake arterial carbon dioxide. SDB was also homogenously present in preserved ejection fraction (EF) CHF. CONCLUSION: Most of the CHF patients were found to have SDB with the utility of PSG. Local CHF guidelines should include sleep testing for all patients with CHF.The study is registered on ClinicalTrials.gov (NCT05332223) as 'The Epidemiological Characteristics of SDB in Patients with Reduced or Preserved EF CHF'.

Case report of hypoglossal nerve stimulation therapy failure due to significant underlying central sleep apnea.

Hypoglossal nerve stimulation is indicated for obstructive sleep apnea but is ineffective in treating central sleep apnea. We describe 2 patients implanted with hypoglossal nerve stimulation after being diagnosed with obstructive sleep apnea at outside sleep laboratories and failing a trial of continuous positive airway pressure therapy. Despite successful hypoglossal nerve stimulation implantation, the patients continued to have persistent symptoms with residual apnea-hypopnea indices above 25 events/h. Although obstructive sleep apnea was the presenting diagnosis, we discovered a significant central sleep apnea component in the original diagnostic sleep data upon careful review. One patient was confirmed to have a central sleep apnea-predominant sleep disorder and improved with adaptive servo-ventilation therapy. The other was diagnosed with central sleep apnea and severe periodic limb movement disorder, and improved with medication. Based on these sleep apnea cases, we propose guidelines emphasizing the importance of reviewing basic clinical information upon treatment failure and initiating multidisciplinary collaboration early in the treatment course. CITATION: Banerjee D, Lee C-H, Im K. Case report of hypoglossal nerve stimulation therapy failure due to significant underlying central sleep apnea. J Clin Sleep Med. 2024;20(6):1003-1007.

An adolescent with Wolfram syndrome and central sleep apnea.

Wolfram syndrome is a rare autosomal recessive disorder affecting approximately 1 in 500,000 individuals. The disorder is most commonly caused by mutations in the WFS1 gene, which encodes an endoplasmic reticulum protein, wolframin, which is thought to protect against endoplasmic reticulum stress-related apoptosis. The major clinical findings of Wolfram syndrome are diabetes mellitus and optic atrophy, both of which usually appear before 16 years of age. Common additional findings include sensorineural hearing impairment, central diabetes insipidus, nonautoimmune hypothyroidism, delayed puberty, neurogenic bladder, cerebellar ataxia, and psychiatric disorders. Central sleep apnea is an uncommon but serious feature of Wolfram syndrome. However, the clinical details of this manifestation have not been documented. Herein, we report an adolescent with recently diagnosed Wolfram syndrome who demonstrated severe central sleep apnea on polysomnography testing. CITATION: Harris JC, Kenkare JD, Schramm CM. An adolescent with Wolfram syndrome and central sleep apnea. J Clin Sleep Med. 2024;20(7):1205-1208.

Type one chiari malformation as a cause of central sleep apnea and hypoventilation in children.

OBJECTIVES: Chiari type 1 malformation (CM1) may occasionally lead to central sleep apnea (CSA). We studied, in a large clinical cohort of pediatric CM1 patients, the effect of CM1 on breathing during sleep. METHODS: This is a retrospective single pediatric pulmonology center study with a systematic evaluation of pediatric CM1 patients under age 18 with polysomnography (PSG) during 2008-2020. Children with syndromes were excluded. All patients had undergone head and spine magnetic resonance imaging. RESULTS: We included 104 children with CM1 with a median age of 7 (interquartile range (IQR) 5-13) years. The median extent of tonsillar descent (TD) was 13 (IQR 10-18) mm. Syringomyelia was present in 19 children (18%). Of all children, 53 (51%) had normal PSG, 35 (34%) showed periodic breathing or central apnea and hypopnea index ≥5 h-1, and 16 (15%) displayed features of compensated central hypoventilation and end-tidal or transcutaneous carbon dioxide 99th percentile level above 50 mmHg. TD had the best predictive value for central breathing disorders. In a linear model, both age (61%) and TD (39%) predicted median breathing frequency (R = 0.33, p < 0.001). CONCLUSIONS: Although severe CSA is a rare complication of brainstem compression in pediatric patients with CM1, short arousal-triggered episodes of periodic breathing and mild compensated central hypoventilation are common. TD shows the best but still poor prediction of the presence of a central breathing disorder. This highlights the use of PSG in patient evaluation. Posterior fossa decompression surgery effectively treats central breathing disorders.

Effect of adenotonsillectomy on central sleep apnea: A scoping review.

OBJECTIVE: The purpose of this study was to assess the effects of adenotonsillectomy (A&T) on reducing central sleep apnea (CSA) in children and adolescents with obstructive sleep apnea (OSA). METHODS: A review of the PubMed database was conducted. Two researchers independently reviewed the articles from the literature search and selected papers for further review if they met inclusion criteria. Included studies were prospective studies and case series whose patients were children 18 years or younger undergoing adenotonsillectomy for obstructive sleep apnea with reported pre and postoperative central apnea indexes (CAI). RESULTS: Of the 107 articles initially identified, 18 underwent full length review, and ultimately 15 for final review. All studies reported marked improvement of central sleep apnea indexes after adenotonsillectomy. Two studies found resolution of CSA in 66.7 % and 73.7 % of patients respectively. The remaining four studies found significant reductions in CAI in 43.9 %-93 % of patients. The degree of reduction varied from 40.9 % to 80 %. DISCUSSION: Adenotonsillectomy improves and at times resolves CSA in pediatric patients with concomitant OSA.

Images: Atypical presentation of congenital central hypoventilation syndrome in an infant with central and obstructive sleep apnea.

Congenital central hypoventilation syndrome (CCHS), a rare disease caused by paired-like homeobox 2B variants, affects control of breathing. We report on a 21-month-old boy with CCHS caused by a novel nonpolyalanine repeat mutation, neuroblastoma, severe obstructive and central sleep apnea, and sleep-related hypoxemia without hypoventilation. At 10 months, due to persistent central sleep apnea during serial polysomnography, bilevel positive airway pressure therapy was initiated despite the absence of hypoventilation. Nonpolyalanine repeat mutations are associated with severe phenotypes requiring continuous assisted ventilation, Hirschsprung's disease, and neural crest tumors; however, our patient had a relatively milder respiratory phenotype requiring sleep-only assisted ventilation without tracheostomy. Although alveolar hypoventilation is the hallmark of CCHS, our patient lacked hypoventilation. Bilevel positive airway pressure could be considered in some infants with CCHS requiring sleep-only assisted ventilation for tracheostomy avoidance. Our case demonstrates the expanding phenotypic spectrum in CCHS and the importance of formulating an individualized care plan. CITATION: Fain ME, Raghunandan S, Pencheva B, Leu RM, Kasi AS. Images: atypical presentation of congenital central hypoventilation syndrome in an infant with central and obstructive sleep apnea. J Clin Sleep Med. 2024;20(3):478-481.

Central sleep apnea and exposure to ambient hydrogen sulfide emissions from massive strandings of decomposing sargassum in the Caribbean.

BACKGROUND: Sargassum invasion of Caribbean and American shorelines is a recurring environmental hazard. Potential health effects of long-term chronic exposure to sargassum gaseous emissions, notably hydrogen sulfide (H2S), are overlooked. H2S plays an important role in neurotransmission and is involved in generating and transmitting respiratory rhythm. Central sleep apnea (CSA) has been attributed to the depression of respiratory centers. OBJECTIVE: Evaluate the effects of exposure to sargassum-H2S on CSA. METHODS: This study, set in the Caribbean, describes the clinical and polysomnographic characteristics of individuals living and/or working in areas impacted by sargassum strandings, in comparison with non-exposed subjects. Environmental exposure was estimated by the closest ground H2S sensor. Multivariate linear regression was applied to analyze CSA changes according to cumulative H2S exposure over time. Effects of air pollution and other sargassum toxic compounds (NH3) on CSA were also controlled. RESULTS: Among the 685 study patients, 27 % were living and/or working in sargassum impacted areas. Compared with non-exposed patients, exposed ones had similar sleep apnea syndrome risk factors, but had increased levels of CSA events (expressed as absolute number or % of total sleep apnea). Multivariate regression retained only male gender and mean H2S concentration over a 6-month exposure period as independent predictors of an increase in CSA events. A minimal exposure length of 1 month generated a significant rise in CSA events, with the latter increasing proportionally with a cumulative increase in H2S concentration over time. CONCLUSION: This pioneer work highlights a potential effect of sargassum-H2S on the central nervous system, notably on the modulation of the activity of the brain's respiratory control center. These observations, jointly with previous studies from our group, constitute a body of evidence strongly supporting a deleterious effect of sargassum-H2S on the health of individuals chronically exposed to low to moderate concentration levels over time.

The OSA patient journey: pathways for diagnosis and treatment among commercially insured individuals in the United States.

STUDY OBJECTIVES: The aims of this study were to characterize obstructive sleep apnea (OSA) care pathways among commercially insured individuals in the United States and to investigate between-groups differences in population, care delivery, and economic aspects. METHODS: We identified adults with OSA using a large, national administrative claims database (January 1, 2016-February 28, 2020). Inclusion criteria included a diagnostic sleep test on or within ≤ 12 months of OSA diagnosis (index date) and 12 months of continuous enrollment before and after the index date. Exclusion criteria included prior OSA treatment or central sleep apnea. OSA care pathways were identified using sleep testing health care procedural health care common procedure coding system/current procedural terminology codes then selected for analysis if they were experienced by ≥ 3% of the population and assessed for baseline demographic/clinical characteristics that were also used for model adjustment. Primary outcome was positive airway pressure initiation rate; secondary outcomes were time from first sleep test to initiation of positive airway pressure, sleep test costs, and health care resource utilization. Associations between pathway type and time to treatment initiation were assessed using generalized linear models. RESULTS: Of 86,827 adults with OSA, 92.1% received care in 1 of 5 care pathways that met criteria: home sleep apnea testing (HSAT; 30.8%), polysomnography (PSG; 23.6%), PSG-Titration (19.8%), Split-night (14.8%), and HSAT-Titration (3.2%). Pathways had significantly different demographic and clinical characteristics. HSAT-Titration had the highest positive airway pressure initiation rate (84.6%) and PSG the lowest (34.4%). After adjustments, time to treatment initiation was significantly associated with pathway (P < .0001); Split-night had shortest duration (median, 28 days), followed by HSAT (36), PSG (37), PSG-Titration (58), and HSAT-Titration (75). HSAT had the lowest sleep test costs and health care resource utilization. CONCLUSIONS: Distinct OSA care pathways exist and are associated with differences in population, care delivery, and economic aspects. CITATION: Wickwire EM, Zhang X, Munson SH, et al. The OSA patient journey: pathways for diagnosis and treatment among commercially insured individuals in the United States. J Clin Sleep Med. 2024;20(4):505-514.

Ventricular assist devices and sleep-disordered breathing-A mechanical heart stimulating a sleepy brain.

Sleep-disordered breathing, including obstructive sleep apnea (OSA) and central sleep apnea (CSA), is common in severe heart failure (HF) patients. There is limited data on the effect of left ventricular assist devices (LVAD) on sleep apnea. We performed a retrospective review of 350 durable LVAD patients and found 5 with a history of pre- and post-LVAD sleep studies. All five patients had OSA, and three had concomitant CSA. We observed reduced apnea-hypopnea index following LVAD placement. This was due to a near abolishment of CSA in three mixed sleep apnea patients-as seen by a central apnea index improvement from an average of 25.9 ± 13.1 to 1.4 ± 2.5 events per hour (p = 0.063). LVAD placement was associated with an increase in thermodilution cardiac output from 2.7 ± 0.6 to 4.1 ± 1.1 L/min (p = 0.014). These findings support chemoreception physiology seen in patients with poor circulation and the effect of restoring this circulation with LVAD support.

FACE study: 2-year follow-up of adaptive servo-ventilation for sleep-disordered breathing in a chronic heart failure cohort.

BACKGROUND: Sleep-disordered breathing (SDB) is a common comorbidity in patients with heart failure (HF) and is associated with worse prognosis. OBJECTIVES: This study evaluated the effects of adaptive servo-ventilation (ASV) on morbidity and mortality in a large heterogeneous population of HF patients with different etiologies/phenotypes. METHODS: Consecutive HF patients with predominant central sleep apnea (± obstructive sleep apnea) indicated for ASV were included; the control group included patients who refused or stopped ASV before three months follow-up. Six homogenous clusters were determined using the latent class analysis (LCA) method. The primary endpoint was time to composite first event (all-cause death, lifesaving cardiovascular intervention, or unplanned hospitalization for worsening of chronic HF). RESULTS: Of 503 patients at baseline, 324 underwent 2-year follow-up. Compared to control group, 2-year primary endpoint event-free survival was significantly greater in patients in ASV group only in univariable analysis (1.67, 95% [1.12-2.49]; p = 0.01). Secondary endpoints, event-free of cardiovascular death or heart failure-related hospitalization and all-cause death or all-cause hospitalization were positively impacted by ASV (univariate and multivariable analysis). LCA identified two groups, with preserved and mid-range left ventricular ejection fraction (LVEF) and severe hypoxia, in whom ASV increase prognosis benefit. CONCLUSIONS: Patients with HF and SDB are a highly heterogeneous group identified using LCA. Systematic deep phenotyping is essential to ensure that ASV is prescribed to those benefit from therapy, as ASV use in patients with severe hypoxic burden and those with HFpEF was associated with a significant reduction in cardiovascular events and mortality. CLINICAL TRIAL REGISTRATION: https://clinicaltrials.gov/ct2/show/NCT01831128.

Adaptive servo-ventilation for sleep-disordered breathing in patients with heart failure with reduced ejection fraction (ADVENT-HF): a multicentre, multinational, parallel-group, open-label, phase 3 randomised controlled trial.

BACKGROUND: In patients with heart failure and reduced ejection fraction, sleep-disordered breathing, comprising obstructive sleep apnoea (OSA) and central sleep apnoea (CSA), is associated with increased morbidity, mortality, and sleep disruption. We hypothesised that treating sleep-disordered breathing with a peak-flow triggered adaptive servo-ventilation (ASV) device would improve cardiovascular outcomes in patients with heart failure and reduced ejection fraction. METHODS: We conducted a multicentre, multinational, parallel-group, open-label, phase 3 randomised controlled trial of peak-flow triggered ASV in patients aged 18 years or older with heart failure and reduced ejection fraction (left ventricular ejection fraction ≤45%) who were stabilised on optimal medical therapy with co-existing sleep-disordered breathing (apnoea-hypopnoea index [AHI] ≥15 events/h of sleep), with concealed allocation and blinded outcome assessments. The trial was carried out at 49 hospitals in nine countries. Sleep-disordered breathing was stratified into predominantly OSA with an Epworth Sleepiness Scale score of 10 or lower or predominantly CSA. Participants were randomly assigned to standard optimal treatment alone or standard optimal treatment with the addition of ASV (1:1), stratified by study site and sleep apnoea type (ie, CSA or OSA), with permuted blocks of sizes 4 and 6 in random order. Clinical evaluations were performed and Minnesota Living with Heart Failure Questionnaire, Epworth Sleepiness Scale, and New York Heart Association class were assessed at months 1, 3, and 6 following randomisation and every 6 months thereafter to a maximum of 5 years. The primary endpoint was the cumulative incidence of the composite of all-cause mortality, first admission to hospital for a cardiovascular reason, new onset atrial fibrillation or flutter, and delivery of an appropriate cardioverter-defibrillator shock. All-cause mortality was a secondary endpoint. Analysis for the primary outcome was done in the intention-to-treat population. This trial is registered with ClinicalTrials.gov (NCT01128816) and the International Standard Randomised Controlled Trial Number Register (ISRCTN67500535), and the trial is complete. FINDINGS: The first and last enrolments were Sept 22, 2010, and March 20, 2021. Enrolments terminated prematurely due to COVID-19-related restrictions. 1127 patients were screened, of whom 731 (65%) patients were randomly assigned to receive standard care (n=375; mean AHI 42·8 events per h of sleep [SD 20·9]) or standard care plus ASV (n=356; 43·3 events per h of sleep [20·5]). Follow-up of all patients ended at the latest on June 15, 2021, when the trial was terminated prematurely due to a recall of the ASV device due to potential disintegration of the motor sound-abatement material. Over the course of the trial, 41 (6%) of participants withdrew consent and 34 (5%) were lost to follow-up. In the ASV group, the mean AHI decreased to 2·8-3·7 events per h over the course of the trial, with associated improvements in sleep quality assessed 1 month following randomisation. Over a mean follow-up period of 3·6 years (SD 1·6), ASV had no effect on the primary composite outcome (180 events in the control group vs 166 in the ASV group; hazard ratio [HR] 0·95, 95% CI 0·77-1·18; p=0·67) or the secondary endpoint of all-cause mortality (88 deaths in the control group vs. 76 in the ASV group; 0·89, 0·66-1·21; p=0·47). For patients with OSA, the HR for all-cause mortality was 1·00 (0·68-1·46; p=0·98) and for CSA was 0·74 (0·44-1·23; p=0·25). No safety issue related to ASV use was identified. INTERPRETATION: In patients with heart failure and reduced ejection fraction and sleep-disordered breathing, ASV had no effect on the primary composite outcome or mortality but eliminated sleep-disordered breathing safely. FUNDING: Canadian Institutes of Health Research and Philips RS North America.

Association and risk factors of pediatric pulmonary hypertension with obstructive sleep apnea: A national study utilizing the Kids' Inpatient Database (KID).

STUDY OBJECTIVE: Assess the prevalence of and risk factors for pediatric pulmonary hypertension (PH) in the 2016 Kids' Inpatient Database (KID), including obstructive sleep apnea (OSA) and obesity. METHODS: Retrospective cross-sectional cohort study utilizing 6,081,132 weighted pediatric discharges from the 2016 KID. Study variables included age, length of stay, mortality, gender, hospital region, primary payer, race, median household income for patient's ZIP code, OSA, central sleep apnea (CSA), obesity, Down syndrome, sickle cell disease (SCD), thalassemia, congenital heart disease (CHD), hypertension, asthma and chronic lung disease of prematurity (CLDP). PH was the primary outcome of interest. Bivariate and multivariable logistic regression models were utilized with odds ratios and 95 % confidence intervals. RESULTS: The mean age was 3.76 years, the mean hospital length of stay was 3.85 days, 48.9 % were male, 52.6 % had government health insurance, 51.0 % were White, 16.1 % were Black, 21.1 % were Hispanic, 5.0 % were Asian or Pacific Islander, 0.80 % were Native American and 6.1 % identified as "other". The prevalence of PH was 0.21 % (12,777 patients). There were 37,631 patients with OSA and the prevalence of PH among this cohort was 3.3 %, over 10x greater than the overall prevalence of PH in the 2016 KID (0.21 %). Risk factors associated with PH included CLDP, CHD, Down syndrome, asthma, OSA, CSA, hypertension, SCD, obesity, race/ethnicity, government insurance, age, male gender (p < 0.0001), and hospital region (p = 0.0002). CONCLUSIONS: Several risk factors were independently associated with PH, such as OSA, CSA, obesity, asthma, and insurance status. Prospective multi-institutional studies are needed to assess the relationships between these risk factors, severity metrics, and causative links in the development of PH; in addition to identifying children with OSA who are most likely to benefit from cardiopulmonary screening prior to adenotonsillectomy. LEVEL OF EVIDENCE: Level III.

Circulating miR-133a-3p defines a low-risk subphenotype in patients with heart failure and central sleep apnea: a decision tree machine learning approach.

BACKGROUND: Patients with heart failure with reduced ejection fraction (HFrEF) and central sleep apnea (CSA) are at a very high risk of fatal outcomes. OBJECTIVE: To test whether the circulating miRNome provides additional information for risk stratification on top of clinical predictors in patients with HFrEF and CSA. METHODS: The study included patients with HFrEF and CSA from the SERVE-HF trial. A three-step protocol was applied: microRNA (miRNA) screening (n = 20), technical validation (n = 60), and biological validation (n = 587). The primary outcome was either death from any cause, lifesaving cardiovascular intervention, or unplanned hospitalization for worsening of heart failure, whatever occurred first. MiRNA quantification was performed in plasma samples using miRNA sequencing and RT-qPCR. RESULTS: Circulating miR-133a-3p levels were inversely associated with the primary study outcome. Nonetheless, miR-133a-3p did not improve a previously established clinical prognostic model in terms of discrimination or reclassification. A customized regression tree model constructed using the Classification and Regression Tree (CART) algorithm identified eight patient subphenotypes with specific risk patterns based on clinical and molecular characteristics. MiR-133a-3p entered the regression tree defining the group at the lowest risk; patients with log(NT-proBNP) ≤ 6 pg/mL (miR-133a-3p levels above 1.5 arbitrary units). The overall predictive capacity of suffering the event was highly stable over the follow-up (from 0.735 to 0.767). CONCLUSIONS: The combination of clinical information, circulating miRNAs, and decision tree learning allows the identification of specific risk subphenotypes in patients with HFrEF and CSA.

Prevalence of central sleep apnea in people with tetraplegic spinal cord injury: a retrospective analysis of research and clinical data.

STUDY OBJECTIVES: Over 80% of people with tetraplegia have sleep-disordered breathing (SDB), but whether this is predominantly obstructive or central is unclear. This study aimed to estimate the prevalence of central sleep apnea (CSA) in tetraplegia and the contributions of central, obstructive, and hypopnea respiratory events to SDB summary indices in tetraplegia. METHODS: Research and clinical data from 606 individuals with tetraplegia and full overnight polysomnography were collated. The proportions of different respiratory event types were calculated; overall and for mild, moderate, and severe disease. The prevalence of Predominant CSA (Central Apnea Index [CAI] ≥ 5 and more central than obstructive apneas) and Any CSA (CAI ≥ 5) was estimated. Prevalence of sleep-related hypoventilation (SRH) was estimated in a clinical sub-cohort. RESULTS: Respiratory events were primarily hypopneas (71%), followed by obstructive (23%), central (4%), and mixed apneas (2%). As severity increased, the relative contribution of hypopneas and central apneas decreased, while that of obstructive apneas increased. The prevalence of Predominant CSA and Any CSA were 4.3% (26/606) and 8.4% (51/606) respectively. Being male, on opiates and having a high tetraplegic spinal cord injury were associated with CSA. SRH was identified in 26% (26/113) of the clinical sub-cohort. CONCLUSIONS: This is the largest study to characterize SDB in tetraplegia. It provides strong evidence that obstructive sleep apnea is the predominant SDB type; 9-18 times more prevalent than CSA. The prevalence of CSA was estimated to be 4%-8%, significantly lower than previously reported.