Central Sleep Apnea Research Articles

Abstract 12622: Long Term Use of Adaptive Servo Ventilation Improves and Maintains Cardiac Function in Patients With Heart Failure With Central Sleep Apnea and Prevents Readmission Due to Worsening Heart Failure Compared to Short Term Use

Introduction: Central sleep apnea (CSA) is closely associated with poor prognosis in heart failure (HF) patients. Adaptive servo-ventilation (ASV) was expected as a new treatment for HF patients with CSA. However, the efficacy of ASV is controversial, especially the efficacy of long-term use has remained unclear. Methods: We retrospectively examined all HF patients with CSA treated with ASV seen between May 2008 and November 2022 in our hospital who had not been admitted to the hospital due to worsening HF in the 6 months before initiating ASV therapy. We divided them into 2 groups: (A) non-continues-ASV-treated patients; (B) continues-ASV-treated patients. The outcome was a composite of readmission due to worsening HF and all-cause mortality. Results: During a median follow-up of 10.3 years after leaving the hospital, 11 patients died out of 101 patients. Twenty-two patients (group A) could not continue to use ASV because of its discomfort. Seventy-nine patients (group B) could continue to use the ASV device at night after leaving the hospital over a long period. There were almost no significant differences in the baseline characteristics between the two groups. In group B, during 6-, 12-, and 24-month observations, left ventricular ejection fraction (46.4 +/- 17.9 to 47.1 +/- 15.6, 49.8 +/- 15.8, and 48.2+/- 18.9%, p<0.05 compared with baseline) and brain natriuretic peptide (685.5 +/- 1087.2 to 233.1+/- 362.9, 391.8 +/- 929.0 and 166.9 +/- 195.1 pg/ml, p<0.05 compared with baseline) improved significantly. And there was significantly less readmission by worsening HF than in group A (log-rank P<0.001). However, there were no significant differences in all-cause mortality between the two groups (log-rank P=0.221). Conclusions: This study showed that long-term ASV therapy for more than 10 years reduced readmission by worsening HF with CSA patients compared to short-term use due to improved and maintained cardiac function but did not affect mortality.

Central sleep apneas with Cheyne-Stokes breathing in a patient with narcolepsy type 1

Central sleep apneas with Cheyne-Stokes breathing in a patient with narcolepsy type 1

Prevalence of Sleep-Disordered Breathing in Prader-Willi Syndrome.

Sleep-disordered breathing (SDB) is common in patients with Prader-Willi Syndrome (PWS). However, the prevalence of SDB varies widely between studies. Early identification of SDB and factors contributing to its incidence is essential, particularly when considering growth hormone (GH) therapy. The aims of the study were to describe the prevalence and phenotypes of sleep-disordered breathing (SDB) in patients with Prader-Willi syndrome (PWS) and to determine the effects of age, gender, symptoms, GH therapy and body mass index on SDB severity. This study was a retrospective chart review of all patients with genetically confirmed Prader-Willi syndrome who underwent diagnostic overnight polysomnography (PSG) in the sleep laboratory at Sidra Medicine. Clinical and PSG data of enrolled patients were collected. We identified 20 patients (nine males, eleven females) with PWS who had overnight sleep polysomnography (PSG) at a median age (IQR) of 5.83 (2.7-12) years. The median apnea-hypopnea index (AHI) was 8.55 (IQR 5.8-16.9) events/hour. The median REM-AHI was 27.8 (IQR 15-50.6) events/hour. The median obstructive apnea-hypopnea index (OAHI) was 7.29 (IQR 1.8-13.5) events/hour. The median central apnea-hypopnea index (CAHI) was 1.77 (IQR 0.6-4.1) events/hour. Nineteen patients (95%) demonstrated SDB by polysomnography (PSG) based on AHI ≥1.5 events/hour. Nine patients (45%) were diagnosed with obstructive sleep apnea (OSA). Three patients (15%) were diagnosed with central sleep apnea (CSA). Seven patients (35%) were diagnosed with mixed sleep apnea. No correlations were observed between AHI and age, gender, BMI, symptoms, or GH therapy. However, REM-AHI was significantly correlated with BMI (P=0.031). This study shows a high prevalence of SDB among our patients with PWS. Obstructive sleep apnea was the predominant phenotype. BMI was the only predictor for high REM-AHI. Further studies of large cohorts are warranted to define SDB in PWS and design the appropriate treatment.

Relationships between Heart Chamber Morphology or Function and Respiratory Parameters in Patients with HFrEF and Various Types of Sleep-Disordered Breathing.

Sleep-disordered breathing (SDB), i.e., central sleep apnea (CSA) and obstructive sleep apnea (OSA), affects the prognosis of patients with heart failure with reduced ejection fraction (HFrEF). The study assessed the relationships between heart chamber size or function and respiratory parameters in patients with HFrEF and various types of SDB. The 84 participants were patients aged 68.3 ± 8.4 years (80% men) with an average left ventricular ejection fraction (LVEF) of 25.5 ± 6.85% who qualified for cardioverter-defibrillator implantation with or without cardiac resynchronization therapy. SDB, defined by an apnea-hypopnea index (AHI) ≥ five events/hour, was diagnosed in 76 patients (90.5%); SDB was severe in 31 (36.9%), moderate in 26 (31.0%), and mild in 19 (22.6%). CSA was the most common type of SDB (64 patients, 76.2%). A direct proportional relationship existed only in the CSA group between LVEF or stroke volume (SV) and AHI (p = 0.02 and p = 0.07), and between LVEF or SV and the percentage of total sleep time spent with hemoglobin oxygen saturation < 90% (p = 0.06 and p = 0.07). In contrast, the OSA group was the only group in which right ventricle size showed a positive relationship with AHI (for basal linear dimension [RVD1] p = 0.06), mean duration of the respiratory event (for RVD1 p = 0.03, for proximal outflow diameter [RVOT proximal] p = 0.009), and maximum duration of respiratory event (for RVD1 p = 0.049, for RVOT proximal p = 0.006). We concluded that in HFrEF patients, SDB severity is related to LV systolic function and SV only in CSA, whereas RV size correlates primarily with apnea/hypopnea episode duration in OSA.

O070 Prevalence of central sleep apnoea in people with tetraplegic spinal cord injury: a retrospective analysis of research and clinical data

Abstract Study Objectives Over 80% of people with tetraplegia have sleep disordered breathing, but whether this is predominantly obstructive or central is unclear. This study aimed to estimate the prevalence of central sleep apnoea (CSA) in tetraplegia and the contributions of central, obstructive and hypopnoea respiratory events to sleep disordered breathing 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 apnoea index 5 and more central than obstructive apnoeas) and Any CSA (central apnoea index  5) was estimated. Prevalence of sleep-related hypoventilation was estimated in a clinical sub-cohort. Results Respiratory events were primarily hypopnoeas (71%), followed by obstructive (23%), central (4%) and mixed apnoeas (2%). As severity increased, the relative contribution of hypopnoeas and central apnoeas decreased, while that of obstructive apnoeas 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. Sleep-related hypoventilation was identified in 26% (26/113) of the clinical sub-cohort. Conclusions This is the largest study to characterize sleep disordered breathing in tetraplegia. It provides strong evidence that obstructive sleep apnoea is the predominant sleep disordered breathing type; 9-18 times more prevalent than CSA. The prevalence of CSA was estimated to be 4-8%, significantly lower than previously reported.

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

BackgroundPatients with heart failure with reduced ejection fraction (HFrEF) and central sleep apnea (CSA) are at a very high risk of fatal outcomes.ObjectiveTo test whether the circulating miRNome provides additional information for risk stratification on top of clinical predictors in patients with HFrEF and CSA.MethodsThe 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.ResultsCirculating 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).ConclusionsThe combination of clinical information, circulating miRNAs, and decision tree learning allows the identification of specific risk subphenotypes in patients with HFrEF and CSA.

Sleep Disordered Breathing in Children with Neuromuscular Disease.

Sleep disordered breathing (SDB) in children with neuromuscular disease (NMD) is more prevalent compared to the general population, and often manifests as sleep-related hypoventilation, sleep-related hypoxemia, obstructive sleep apnea, central sleep apnea, and/or disordered control of breathing. Other sleep problems include, sleep fragmentation, abnormal sleep architecture, and nocturnal seizures in certain neuromuscular diseases. The manifestation of sleep disordered breathing in children depends on the extent, type, and progression of neuromuscular weakness, and in some instances, may be the first sign of a neuromuscular weakness leading to diagnosis of an NMD. In-lab diagnostic polysomnography (PSG) remains the gold standard for the diagnosis of sleep disordered breathing in children, but poses several challenges, including access to many children with neuromuscular disease who are non-ambulatory. If SDB is untreated, it can result in significant morbidity and mortality. Hence, we aimed to perform a comprehensive review of the literature of SDB in children with NMD. This review includes pathophysiological changes during sleep, clinical evaluation, diagnosis, challenges in interpreting PSG data using American Academy of Sleep (AASM) diagnostic criteria, management of SDB, and suggests areas for future research.

Polysomnographic findings in the ultra-rare McLeod syndrome: further documentation of sleep apnea as a possible feature.

McLeod syndrome is a very rare multisystemic neurodegenerative disease linked to mutations in the XK gene. It has cardiac, neurologic, and neuromuscular manifestations and shares similarities with Huntington's disease. The aim of this study was to evaluate sleep patterns of patients affected by McLeod syndrome. This retrospective case series of four males who underwent diagnostic polysomnography (mean age 53.8 ± 2.5 years) includes self-reported and objective evaluation of sleep using the Epworth Sleepiness Scale, genetic tests, documentation of clinical course and features, and laboratory-based full-night attended video-polysomnography. In three out of four patients, an Epworth Sleepiness Scale score ≥ 7 was evident. The average apnea-hypopnea index was 45.0 ± 19.0, with predominantly obstructive phenotype in three patients and predominant central events (central sleep apnea syndrome) in one patient. A significantly increased periodic limb movement index during sleep was observed in all patients. All patients tolerated continuous positive airway pressure or pressure controlled therapy. Polysomnography of all patients confirmed sleep apnea syndrome as a feature of McLeod syndrome. Three patients were diagnosed with obstructive sleep apnea and one with central sleep apnea syndrome. In addition, periodic limb movement index was increased in all patients. Dieter M, Kevin P, Tobias V, etal. Polysomnographic findings in the ultra-rare McLeod syndrome: further documentation of sleep apnea as a possible feature. J Clin Sleep Med. 2024;20(3):339-344.

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

Study objectiveAssess 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. MethodsRetrospective 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. ResultsThe 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). ConclusionsSeveral 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 evidenceLevel III.

Obstructive sleep apnea in patients with type 2 diabetes mellitus in Egyptian population

BackgroundSleep disordered breathing (SDB) is a widespread disorder with a wide range of harmful outcomes including obstructive sleep apnea (OSA), central sleep apnea (CSA), or sleep-related hypoventilation.PurposeThe aim of the present study was to screen for the occurrence of sleep apnea syndrome in patients with type 2 diabetes mellitus (DM) and to evaluate the relation between the presence of sleep apnea and the level of glycemic control.MethodsThis was a prospective clinical study that enrolled 59 patients who were previously diagnosed as type 2 DM. Sleep study level IV was done using overnight recording of oxygen saturation and pulse.ResultsAmong the studied patients, 42 were females and 17 were males, Their mean age was 59.76 ± 11.13 years. Obstructive sleep apnea was diagnosed in 46 patients (78%). Thirty three (86.8%) patients among those with uncontrolled glycemic level were diagnosed as OSA, whereas 13(61.9%) patients with controlled glycemic level were diagnosed as OSA showing statistically significant difference, p = 0.047. There was no correlation between either HbA1c, age, Mallampati score, or BMI and ODI but there was a correlation between STOP-BANG questionnaire and ODI (P = 0.036). The variables that were significantly related to presence of OSA, were comorbidities, ESS, Mallampati score, STOP-BANG, and sleep symptoms (nocturia and snoring) P value (0.029), (0.031), (0.022), (0.005), (0.049), and (0.012), respectively.ConclusionPatients with type 2 diabetes showed a significant high prevalence of OSA. With significant higher prevalence among patients with uncontrolled DM versus controlled DM.

Safety of Non-Operating Room Anesthesia With Propofol Sedation in Three Pediatric Patients With Central Sleep Apnea.

Children with central sleep apnea may require sedation for procedures, including brain imaging as part of the evaluation of apnea. However, the safety of deep sedation without a protected airway is not known in this patient population. In this case series, we present 3 children with central sleep apnea who were sedated with propofol for brain imaging in a non-operating room setting. All 3 did well with no complications; those with a home oxygen requirement were on oxygen during the procedure but none experienced apnea, desaturation, or respiratory distress. While obstructive sleep apnea is a known contraindication to deep sedation with propofol, it may be safe in pediatric patients with central sleep apnea. Deep sedation may be a good option for these patients, thereby avoiding the need for general anesthesia and placement of an advanced airway.

IMPACT OF CENTRAL SLEEP APNEA ON OUTCOMES IN HOSPITALIZATIONS WITH HEART FAILURE

IMPACT OF CENTRAL SLEEP APNEA ON OUTCOMES IN HOSPITALIZATIONS WITH HEART FAILURE

Enhanced expiratory rebreathing space for high loop gain sleep apnea treatment

The pathophysiology of sleep apnea goes beyond anatomic predisposition to airway collapse and includes additional factors such as arousal threshold and loop gain. High loop gain is a prominent feature in central and complex sleep apnea (with a mixture of obstructive and central features) where relative hypocapnia can lead to respiratory instability and periodic breathing. Existing therapies, including continuous positive airway pressure (CPAP) and adaptive servo-ventilators, often inadequately treat sleep apnea with high loop gain features. Enhanced expiratory rebreathing space (EERS) targets prevention of the hypocapnia that triggers central events in sleep by increasing dead space in amounts less than typical tidal volumes. This is accomplished by covering traditional exhalation ports on positive airway pressure masks and adding small additional tubing with distal exhalation and safety valves. This technique reduces carbon dioxide (CO2) blow-off during arousals and the associated large recovery breaths, typically producing a maximal increase in resting CO2 by 1–2 mmHg, thus increasing the CO2 reserve and making it less likely to encounter the hypocapnic apneic threshold. Typically, the amount of EERS is titrated in response to central events and periodic breathing rather than aiming for a goal CO2 level. Ideally CO2 monitoring is used during titration of EERS and the technique is avoided in the setting of baseline hypercapnia. This method has been used in clinical practice at our sleep center for over 15 years, and retrospective data suggests an excellent safety profile and high rates of successful therapy including in patients who have previously failed CPAP therapy. Limitations include decreased effectiveness in the setting of leak and decreased tolerance of the bulkier circuit. EERS represents a simple, affordable modification of existing positive airway pressure modalities for treatment of central and complex sleep apnea. Areas of future study include randomized controlled trials of the technique and study of use of EERS in combination with adaptive ventilation, and pharmacologic adjuncts targeting high loop gain physiology.

Nighttime Sleep and Respiratory Disturbances in Individuals Receiving Methadone to Treat Opioid Use Disorder.

Opioids are a leading cause of drug overdose deaths in the United States. Methadone used as medication for opioid use disorder (MOUD) reduces drug cravings and promotes abstinence. However, individuals in methadone-based MOUD treatment commonly report subjective sleep complaints and are at risk for respiratory depression from opioids. We investigated nighttime sleep and respiratory function in eight individuals (six women, two men; ages 31-68 years) in their first 90 days of methadone-based MOUD treatment. Participants underwent overnight cardiorespiratory polysomnography. Sleep and respiratory variables were characterized with descriptive statistics for comparison to reference data from similarly aged healthy adults. Although participants spent 8.1 ± 0.3 hours (mean ± SD ) in bed, their total sleep time was only 6.8 ± 1.3 hours. They exhibited longer sleep latency and intermittent wakefulness. Sleep structure was irregular, with disrupted sleep cycles. Participants also displayed a decreased amount of N1 sleep and an increased amount of N3 sleep, compared with reference data. Participants showed respiratory depression, with an average apnea-hypopnea index of 16.5 ± 8.9 events per hour. Central sleep apneas comprised 69.1% ± 20.9% of the respiratory events. A Cheyne-Stokes-like breathing pattern, consisting of 30-second cycles of three central sleep apneas, was observed in 75% of participants. Our results suggest that individuals early in methadone-based MOUD treatment experience disordered sleep and respiratory disturbances. Such nighttime physiological changes may have serious long-term health consequences and contribute to unintended overdose rates. Identifying and treating MOUD individuals with sleep apnea could reduce risk of death.

The Interplay Between Sleep Disorders and Cardiovascular Diseases: A Systematic Review.

Non-communicable diseases (NCDs) have emerged as the predominant cause of global mortality, resulting in a substantial annual loss of human lives. Among these conditions, cardiovascular diseases (CVD) stand out as the primary cause of death. The majority of CVD cases can be attributed to certain factors that, upon modification, have the potential to significantly decrease both the incidence and severity of the disease. For numerous years, the impact of sleep disorders on cardiovascular health has been a prominent subject of extensive discussion. Chronic sleep disturbances are known to have a range of negative health consequences, with the relationship between sleep apnea and hypertension being well-established through numerous studies. However, further exploration is needed to understand other disease associations with sleep apnea and to examine the impact of various sleep disorders, aside from sleep apnea, on cardiovascular health. This systematic review assesses the available evidence on the association between various sleep disorders and cardiovascular diseases by addressing the question: Do sleep disorders contribute to or exacerbate cardiovascular diseases? After a comprehensive review, we identified 122 articles. Following this initial review, seven papers directly aligned with our research topic. Subsequently, we meticulously assessed the remaining seven papers, all meeting our predetermined criteria. Our analysis showed a strong correlation between sleep disruptions and cardiovascular health. Numerous sleep disorders, such as narcolepsy, central sleep apnea, obstructive sleep apnea, and insomnia, have shown different effects on cardiovascular outcomes. Increased risks of illnesses such as acute coronary syndrome (ACS), hypertension, cardiovascular mortality, and coronary artery calcification were included in these consequences. This systematic review underscores the need for early identification and comprehensive management of sleep disturbances to mitigate their potential adverse effects on cardiovascular well-being. Integrating strategies that address sleep disorders and cardiovascular health is imperative in enhancing overall health outcomes. This study paves the way for more effective preventive and therapeutic approaches by focusing on the relationship between sleep disorders and cardiovascular diseases.

Sleep disordered breathing in infants identified through newborn screening with spinal muscular atrophy

BackgroundSpinal muscular atrophy (SMA) is a genetic disorder that may result in neuromuscular weakness and respiratory insufficiency. Gene replacement therapy has changed the trajectory of this condition, but long-term outcomes related to sleep disordered breathing are not known. MethodsThis was a retrospective review of infants with SMA identified via newborn screening who subsequently received onasemnogene abeparvovec at the Hospital for Sick Children (Ontario, Canada). Polysomnograms were conducted at the time of confirmed diagnosis as well as regularly thereafter. ResultsEleven children (4 female) were identified via newborn screen (7 with 2 copies of the SMN2 gene and 4 with 3 copies of the SMN2 gene) and received onasemnogene abeparvovec at a median age of 3.6 weeks. All eleven infants met criteria for sleep disordered breathing based on their first completed polysomnograms but improved over time. Three infants required respiratory technology, including a premature infant who was prescribed nocturnal supplemental oxygen therapy for central sleep apnea and two symptomatic infants with neuromuscular weakness who required nocturnal noninvasive ventilation. We did not find a correlation between motor scores and polysomnogram parameters. ConclusionChildren treated with onasemnogene abeparvovec have reduced sleep disordered breathing over time. Polysomnograms revealed abnormal parameters in all children, but the clinical significance of these findings was unclear for children who were asymptomatic for sleep disordered breathing or neuromuscular weakness. These results highlight the need to evaluate both motor scores and respiratory symptoms to ensure a holistic evaluation of clinical status.

Occurrence of sleep-disordered breathing in children with pulmonary hypertension.

Obstructive sleep apnea (OSA) has been associated with pulmonary hypertension (PH) through a complex and bidirectional relationship. The prevalence of OSA and other forms of sleep-disordered breathing (SDB) among children with PH is not well understood. A better understanding could help elucidate contributing factors for PH, guide diagnostic testing, and inform therapies. We therefore determined the proportion of SDB codiagnosis and OSA risk factors among a cohort of children with PH. Retrospective chart review was performed for children 0-21 years old with PH who underwent polysomnography (PSG) between 1 January2010 and 31 August2020. The primary outcome was OSA occurrence and risk based on demographics, diagnoses, and PH classification. The secondary outcome was occurrence and risk of other SDB diagnoses based on PH classification. Among 89 children identified, diagnoses included OSA (N = 79, 89%), central sleep apnea (N = 11, 12%), sleep-related hypoventilation (N = 6, 7%), and non-apneic hypoxemia (N = 28, 31%). Trisomy 21 diagnosis (N = 38, 43%) was associated with increased OSA risk (RR: 1.24, 95% CI: [1.09-1.42]) and age >12 months at PSG was associated with decreased OSA risk (N = 52, 58%, RR: 0.60, 95% CI: [0.45-0.81]). There was no difference in SDB risk based on Group 1 (N = 56, 63%) or Group 3 (N = 33, 37%) PH and no difference in OSA severity based on demographics and diagnoses. OSA was diagnosed among a majority of children with PH, and other SDB diagnoses were identified in a significant proportion of children. These findings support routine screening for SDB with PSGin children with PH.

Association of hypoxic burden metrics with cardiovascular outcomes in heart failure and sleep-disordered breathing.

Heart failure (HF) and sleep-disordered breathing (SDB) frequently coexist. We aimed to compare the prognostic value of different nocturnal hypoxic burden metrics in hospitalized HF patients. HF patients underwent polygraphy screening for SDB in this prospective cohort. Hypoxic burden metrics assessed using pulse oximetry included time<90% oxygen saturation (T90), proportion of total recording time<90% oxygen saturation (TRT90), oxygen desaturation index (ODI), and mean oxygen saturation (meanSO2 ). The prespecified endpoints were the composite of cardiovascular death or admission for worsening HF. This study included 764 hospitalized HF patients, 16.5% and 36.6% of whom had obstructive and central sleep apnoea, respectively. With a median follow-up time of 2.2years, endpoint events occurred in 410 (53.7%) patients. In univariate and multivariate analyses, T90, TRT90, and meanSO2 were substantially associated with the composite outcome, whereas ODI was not. After multivariate Cox model adjustment, patients with 5.0≤T90≤52.0min [hazard ratio (HR) 1.32, 95% confidence interval (CI): 1.02-1.71, P=0.034] or T90>52.0min (HR 1.56, 95% CI: 1.21-2.02, P=0.001) had a greater risk of the composite outcome than those with T90<5.0min. The TRT90 and T90 results were similar. Compared with meanSO2 >95%, meanSO2 <93% (HR 1.47, 95% CI: 1.16-1.88, P=0.002) was correlated with adverse outcomes. The hypoxic burden metrics T90, TRT90, and meanSO2 , but not ODI, were independent predictors of cardiovascular death or readmission for worsening HF. Indicators of duration and severity, not just the frequency of nocturnal hypoxaemia, should be valued and considered for intervention to improve outcomes in HF patients.

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

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. 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. 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. 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.

Links between Sleep Apnoea and Insomnia in a British Cohort.

Poor sleep is a major public health problem with implications for a wide range of critical health outcomes. Insomnia and sleep apnoea are the two most common causes of poor sleep, and recent studies have shown that these disorders frequently co-occur. Comorbid insomnia and sleep apnoea can substantially impair quality of life and increase the overall risk of mortality. However, the causal and physiological links between sleep apnoea and insomnia are unclear. It is also unknown whether having a higher risk for one condition can increase the risk of developing the other. Here, we investigated links between sleep apnoea and insomnia in a British population using a combination of self-reported questionnaires and causal inference. We found that 54.3% of the cohort had moderate insomnia, 9.4% had moderate sleep apnoea, and that 6.2% scored high for both conditions. Importantly, having a higher risk of sleep apnoea was associated with a higher risk of insomnia and vice versa. To determine the causal directionality between sleep apnoea and insomnia, we used Mendelian randomisation and found evidence that sleep apnoea could cause insomnia, but not the reverse. To elucidate how both sleep apnoea and insomnia were linked to each other, we looked at the behavioural markers of poor sleep. We found that feeling fatigued after sleeping and having noticeable sleep problems were linked to a higher burden of both sleep apnoea and insomnia. In conclusion, our results show that sleep apnoea increases the risk of developing insomnia, and both conditions can result in fatigue. We highlight the importance of considering and treating the symptoms of both conditions.