Association of Sex With Cardiovascular Outcomes in Heart Failure Patients With Obstructive or Central Sleep Apnea

BACKGROUND

This study investigated the association of sex with cardiovascular outcomes in a prospective cohort of patients with heart failure (HF) with obstructive sleep apnea or central sleep apnea.

METHODS AND RESULTS

Patients were screened for sleep apnea on admission using multichannel cardiopulmonary monitoring from May 2015 to July 2018. The primary outcome was a composite of cardiovascular death or unplanned hospitalization for worsening HF. Ultimately, 453 patients with HF with obstructive sleep apnea or central sleep apnea were included; 71 (15.7%) and 382 (84.3%) were women and men, respectively. During a median follow-up of 2.33 years, 248 (54.7%) patients experienced the primary outcome. In the overall population, after adjusting for potential confounders, women had an increased risk of the primary outcome (66.2% versus 52.6%; hazard ratio [HR], 1.47 [95% CI, 1.05-2.04]; P=0.024) and HF rehospitalization (62.0% versus 46.6%; HR, 1.55 [95% CI, 1.10-2.19]; P=0.013) compared with men but a comparable risk of cardiovascular death (21.1% versus 23.3%; HR, 0.78 [95% CI, 0.44-1.37]; P=0.383). Likewise, in patients with HF with obstructive sleep apnea, women had a higher risk of the primary outcome (81.8% versus 46.3%, HR, 2.37 [95% CI, 1.28-4.38]; P=0.006) and HF rehospitalization (81.8% versus 44.7%, HR, 2.46 [95% CI, 1.32-4.56], P=0.004). However, in patients with HF with central sleep apnea, there was no statistically significant difference between women and men.

CONCLUSIONS

In hospitalized patients with HF, female sex was associated with an increased risk of the primary outcome and HF rehospitalization, especially in those with obstructive sleep apnea. Screening for sleep apnea should be emphasized to improve the prognosis.

REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifier: NCT02664818.

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'.

Sleep disordered breathing assessment in patient with slowly progressive neuromuscular disease

BACKGROUND

Sleep-disordered breathing (SDB) is common in patients with neuromuscular diseases (NMD). Focusing on hypercapnia may lead to the neglect of other SDB such as obstructive and/or central sleep apnea syndrome (SAS). Our objectives were to assess the risk of inappropriate SDB management according to different screening strategies and to evaluate the prevalence and determinants of isolated and overlapping sleep apnea in patients with slowly progressive NMD.

METHODS

This monocentric, cross-sectional, retrospective study analyzed medical records of adult NMD patients referred to a sleep department. Diagnostic strategies, including respiratory polygraphy (RP), nocturnal transcutaneous capnography (tcCO2), and blood gases (BG), were assessed for their performance in diagnosing SDB. Demographics and pulmonary function test results were compared between patients with or without SDB to identify predictors.

RESULTS

Among the 149 patients who underwent a full diagnostic panel (RP + tcCO2 + BG), 109 were diagnosed with SDB. Of these, 33% had isolated SAS, and central apneas were predominant. Using single diagnostic strategies would lead to inappropriate SDB management in two thirds of patients. A combination of 2 diagnostic tools resulted respectively in 21.1, 22.9 and 42.2 % of inappropriate SDB management for RP + tcCO2, RP + BG and tcCO2 + BG.

CONCLUSION

The significant prevalence of sleep apnea syndrome in patients with slowly progressive NMD highlights the need for increased awareness among clinicians. Improved diagnostics involve a systematic approach addressing both sleep apnea and diurnal and nocturnal alveolar hypoventilation to avoid inappropriate management and limit the consequences of SDB.

Central Sleep Apnea in Patients With Coronary Heart Disease Taking P2Y12 Inhibitors

ABSTRACT

Central sleep apnea (CSA) is common in patients with heart failure. Recent studies link ticagrelor use with CSA. We aimed to evaluate CSA prevalence in patients with coronary heart disease (CHD) and whether ticagrelor use is associated with CSA. We reviewed consecutive patients with CHD who underwent a polysomnography (PSG) test over a 5-year period from 3 sleep centers. We sampled patients who were on ticagrelor or clopidogrel during a PSG test at a 1:4 ticagrelor:clopidogrel ratio. Patients with an active opioid prescription during PSG test were excluded. Age, left ventricle (LV) dysfunction, and P2Y12 inhibitor use were included in a multivariate logistic regression. A total of 135 patients were included with 26 on ticagrelor and 109 on clopidogrel (age 64.1 ± 11.4, 32% male). High CSA burden (12%) and strict CSA (4.4%) were more common in patients on ticagrelor than in those on clopidogrel (27% vs. 8.3% and 10.0% vs. 1.8%). Ticagrelor use (vs. clopidogrel) was associated with high CSA burden (OR 3.53, 95% CI 1.04-12.9, P = 0.039) and trended toward significance for strict CSA (OR 6.32, 95% CI 1.03-51.4, P = 0.052) when adjusting for age and LV dysfunction. In an additional analysis also adjusting for history of atrial fibrillation, ticagrelor use and strict CSA became significantly associated (OR 10.0, 95% CI 1.32-117, P = 0.035). CSA was uncommon in patients with CHD undergoing sleep studies. Ticagrelor use (vs. clopidogrel) was associated with high CSA burden and trended toward significance for strict CSA.

Novel Approaches to Sleep Apnea in Heart Failure

Sleep apnea is a serious comorbid condition affecting patients with heart failure. Present in 50% to 75% of heart failure patients, it is often underrecognized, underdiagnosed, and undertreated. Patients with sleep apnea and heart failure are at increased risk of adverse cardiovascular events and sudden death. Treatment of sleep apnea has shown mixed results in reduction of adverse outcomes by sleep apnea type and intervention strategy. Evolving home-based technologies and device therapies present an exciting frontier for patients with sleep apnea and heart failure and an opportunity to improve outcomes. This article reviews novel approaches to sleep apnea in heart failure.

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.

The prevalence of treatment-emergent central sleep apnea with mandibular advancement device therapy

STUDY OBJECTIVES

Treatment-emergent central sleep apnea (TECSA) describes the appearance or persistence of central sleep apnea while undergoing treatment for obstructive sleep apnea. TECSA is well studied in continuous positive airway pressure therapy with an estimated prevalence of 8%. Based on a few case reports, mandibular advancement devices (MAD) may also provoke TECSA. This study aims to gain insight into the prevalence of TECSA with MAD therapy.

METHODS

This retrospective study includes a total of 129 patients with moderate to severe obstructive sleep apnea who were treated with a custom-made titratable MAD. Baseline and follow-up sleep studies were compared to identify patients with TECSA. Since different diagnostic criteria to define TECSA are used in literature, prevalence was calculated according to three definitions (TECSA-1, -2, and -3). Demographics, MAD treatment variables, and findings of the diagnostic polysomnography were compared between TECSA and non-TECSA patients to identify possible predictors.

RESULTS

Depending on the definition used, TECSA was found in 3.1%-7.8% of patients undergoing MAD therapy. TECSA patients had a higher apnea index (9.2 vs 2.0 events/h, P = .042), central apnea-hypopnea index (4.1 vs 0.2 events/h, P = .045) and oxygen desaturation index (23.9 vs 16.3 events/h, P = .018) at baseline compared to non-TECSA patients. No differences were found in demographics and treatment variables.

CONCLUSIONS

These findings demonstrate that TECSA also occurs in patients starting MAD treatment. Patients with TECSA had a higher apnea index, central apnea-hypopnea index, and oxygen desaturation index at baseline compared to non-TECSA patients.

CITATION

Hellemans S, Van de Perck E, Braem MJ, Verbraecken J, Dieltjens M, Vanderveken OM. The prevalence of treatment-emergent central sleep apnea with mandibular advancement device therapy. J Clin Sleep Med. 2023;19(12):2035-2041.

Contribution of central sleep apnea to severe sleep apnea hypopnea syndrome

PURPOSE

Central sleep apnea (CSA) is usually distinguished from obstructive sleep apnea (OSA). In fact, CSA is often a component of severe sleep apnea hypopnea syndrome (SAHS), rather than occurring alone. We investigated the clinical characteristics and polysomnography (PSG) parameters of CSA components in patients with severe SAHS.

METHODS

The clinical characteristics and PSG parameters were retrospectively analyzed.

RESULTS

Pure or dominant CSA was rare (5% of all patients). Of all patients with CSA, 72% also exhibited other apnea subtypes that contributed to severe SAHS. Among patients with severe SAHS, those with CSA were more likely than others to be older; thinner; exhibit higher prevalences of comorbid coronary heart disease, arrhythmia, and heart failure; a higher apnea/hypopnea index (AHI); mixed apnea index (MAI); an elevated oxygen desaturation index (ODI); and more nighttime oxygen saturation levels < 90%. Multivariate logistic regression analysis revealed that older age, comorbid arrhythmia or heart failure, and an elevated ODI were independently associated with CSA.

CONCLUSION

Patients who complain of snoring or apnea may be better evaluated by comprehensive PSG prior to treatment if they are old, show greater hypoxia, or suffer from arrhythmia and/or heart failure, because such patients are more likely than others to exhibit CSA.

The burden of sleep disordered breathing in infants with Down syndrome referred to tertiary sleep center

INTRODUCTION

Children with Down Syndrome (DS) are at high risk of sleep disordered breathing (SDB). We aimed to examine the burden of SDB in infants with DS referred to tertiary sleep center.

METHODS

Infants (≤12 months old) with DS who underwent consecutive polysomnography (PSG) at a single academic sleep center over a 6-year period were included. obstructive sleep apnea (OSA) (obstructive apnea hypopnea index [oAHI]>1/hr), central sleep apnea (central apnea index > 5/h) and the presence of hypoventilation (% time spent with CO2  > 50 mmHg either by end-tidal or transcutaneous> 25% of total sleep time) and hypoxemia (time spent with O2 saturation <88% >5 min) were ascertained.

RESULTS

A total of 40 infants were included (Mean age 6.6 months, male 66%). PSGs consisted of diagnostic (n = 13) and split night (n = 27, 68%) studies. All met criteria for OSA with mean oAHI 34.6/h (32.3). Central sleep apnea was present in 11 (27.5%) of infants. A total of 11 (27.5%) had hypoxemia. Hypoventilation was present in 10 (25%) infants.

CONCLUSION

This study highlights the high prevalence of SDB in infants with DS referred to a sleep center, and supports early PSG assessment in this patient population.

Heart failure is not a determinant of central sleep apnea in the pediatric population

BACKGROUND/OBJECTIVES

Adults with heart failure (HF) have high prevalence of central sleep apnea (CSA). While this has been repeatedly investigated in adults, there is a deficiency of similar research in pediatric populations. The goal of this study was to compare prevalence of CSA in children with and without HF and correlate central apneic events with heart function.

METHODS

Retrospective analysis of data from children with and without HF was conducted. Eligible children were less than 18 years old with echocardiogram and polysomnogram within 6 months of each other. Children were separated into groups with and without HF based on left ventricular ejection fraction (LVEF). Defining CSA as central apnea-hypopnea index (CAHI) more than 1/hour, the cohort was also classified into children with and without CSA for comparative study.

RESULTS

A total of 120 children (+HF: 19, -HF: 101) were included. The +HF group was younger, with higher prevalence of trisomy 21, muscular dystrophy, oromotor incoordination, and structural heart disease. The +HF group had lower apnea-hypopnea index (median: 3/hour vs. 8.6/hour) and lower central apnea index (CAI) (median: 0.2/hour vs. 0.55/hour). Prevalence of CSA was similar in both groups (p = .195). LogCAHI was inversely correlated to age (Pearson correlation coefficient: -0.245, p = .022). Children with CSA were younger and had higher prevalence of prematurity (40% vs. 5.3%). There was no significant difference in LVEF between children with and without CSA. After excluding children with prematurity, relationship between CAHI and age was no longer sustained.

CONCLUSIONS

In contrast to adults, there is no difference in prevalence of CSA in children with and without HF. Unlike in adults, LVEF does not correlate with CAI in children. Overall, it appears that central apneic events may be more a function of age and prematurity rather than of heart function.

Postoperative complications after elective coronary artery bypass grafting surgery in patients with sleep-disordered breathing

BACKGROUND

Sleep-disordered breathing (SDB) may increase the risk of postoperative complications in patients after cardiac surgery. This study evaluated the length of hospital stay as well as postoperative cardiac, respiratory, and renal complications after elective coronary artery bypass grafting (CABG) in patients without SDB, with central sleep apnea (CSA), or with obstructive sleep apnea (OSA).

METHODS

The presence and type of SDB had been assessed with polygraphic recordings in 100 patients the night before elective CABG surgery. SDB was defined as an apnea-hypopnea index (AHI) of ≥ 15/h. Prolonged length of hospital stay (LOS) and postoperative hemodynamic instability due to any cause were retrospectively evaluated as primary endpoints and cardiac, respiratory, and renal complications as secondary endpoints.

RESULTS

37% of patients had SDB, 14% CSA, and 23% OSA. LOS differed significantly between patients without SDB and those with CSA and OSA [median (25;75. percentile): 8.0 days (7.5;11.0) vs. 9.5 days (7.0;12.5) vs. 12.0 days (9.0;17.0), Kruskal-Wallis test between three groups: p = 0.023; OSA vs. no SDB: p = 0.005]. AHI was significantly associated with prolonged LOS [> 9 days; odds ratio (OR) (95% confidence interval): 1.047 (1.001;1.095), p = 0.044]. Prolonged need of vasopressors (≥ 48 h) was observed in 36% of patients without SDB, in 64% with CSA, and in 62% with OSA (p = 0.037). AHI was significantly associated with prolonged (≥ 48 h) need of vasopressors [OR (95% CI): 1.052 (1.002;1.104), p = 0.040], independent of any confounders.

CONCLUSIONS

SDB, particularly OSA, is associated with prolonged LOS after CABG, independent of known confounders. Prolonged LOS in patients with SDB may be due to increased postoperative hemodynamic instability due to any cause.

Sleep-disordered breathing and epicardial adipose tissue in patients with heart failure

BACKGROUND AND AIMS

Sleep-disordered breathing (SDB) is common in patients with heart failure (HF), contributes to the progression of cardiac disease, and is associated with adverse prognosis. Previous evidence indicates that epicardial adipose tissue (EAT) is independently associated with sleep apnea in obese individuals. We explored the relationship between SDB and EAT in HF patients.

METHODS AND RESULTS

EAT thickness was assessed by echocardiography in 66 patients with systolic HF undergoing nocturnal cardiorespiratory monitoring. A significantly higher EAT thickness was found in patients with SDB than in those without SDB (10.7 ± 2.8 mm vs. 8.3 ± 1.8 mm; p = 0.001). Among SDB patients, higher EAT thickness was found in both those with prevalent obstructive sleep apnea (OSA) and those with prevalent central sleep apnea (CSA). Of interest, EAT thickness was significantly higher in CSA than in OSA patients (11.9 ± 2.9 vs. 10.1 ± 2.5 p = 0.022). Circulating plasma norepinephrine levels were higher in CSA than in OSA patients (2.19 ± 1.25 vs. 1.22 ± 0.92 ng/ml, p = 0.019). According to the apnea-hypopnea index (AHI), patients were then stratified in three groups of SDB severity: Group 1, mild SDB; Group 2, moderate SDB; Group 3, severe SDB. EAT thickness progressively and significantly increased from Group 1 to Group 3 (ANOVA p < 0.001). At univariate analysis, only left ventricular ejection fraction and AHI significantly correlated with EAT (p = 0.019 and p < 0.0001, respectively). At multivariate analysis, AHI was the only independent predictor of EAT (β = 0.552, p < 0.001).

CONCLUSIONS

Our results suggest an association between the presence and severity of sleep apneas and cardiac visceral adiposity in HF patients.

High Coronary Heart Disease Risk in Hemodialysis Patients with Central Sleep Apnea: A Pilot Study

BACKGROUND

The high prevalence of sleep apnea is reported in hemodialysis patients despite the low prevalence of obesity. The present study compared the occurrence of central sleep apnea (CSA) in hemodialysis patients with that in non-hemodialysis patients, and its association with new-onset coronary heart disease (CHD) events.

METHODS

Seventy-three hemodialysis and 444 non-hemodialysis patients were examined for CSA and obstructive sleep apnea (OSA) occurrence using polysomnography. Hemodialysis patients were monitored for the occurrence of new-onset CHD events.

RESULTS

Hemodialysis patients had a significantly higher central apnea-hypopnea index (AHI; 0.7, range 0.2-3.1) than age-, sex- and obstructive AHI-matched non-hemodialysis patients (0.1, range 0-1.0; p < 0.001), in contrast with an insignificant difference for obstructive AHI. Furthermore, the prevalence of CSA was significantly higher in the hemodialysis (21.9%) than in the non-hemodialysis group (9.7%; p = 0.004). A significant and negative association existed between log (central AHI + 1) and Kt/V in hemodialysis patients. In the Kaplan-Meier analysis, hemodialysis patients with CSA had a significantly higher rate of new-onset CHD events than those without CSA. Cox proportional-hazards regression analysis identified CSA prevalence as an independent risk factor for the development of a new-onset CHD event, independent of OSA.

CONCLUSIONS

The present study demonstrated that hemodialysis patients had a significantly higher CSA prevalence than non-hemodialysis patients despite similar obstructive AHI, and that hemodialysis patients with CSA had a significantly higher risk for new-onset CHD events than those without CSA independent of obstructive AHI, suggesting CSA as a potential CHD risk specifically in hemodialysis patients.

Association between polymorphisms of the HSPB7 gene and Cheyne-Stokes respiration with central sleep apnea in patients with dilated cardiomyopathy and congestive heart failure

BACKGROUND

CSR-CSA is frequent in patients with CHF. Dilated cardiomyopathy (DCM) is a structural heart disease with strong genetic background, yet one of the leading etiological causes of CHF. Studies have showed that the HSPB7 gene is associated with DCM.

OBJECTIVES

We aimed to explore the prevalence of polymorphisms of the HSPB7 gene in the Chinese Han population with CSR-CSA and CHF caused by DCM.

METHODS

A total of 503 unrelated subjects of the Chinese Han population, including 283 CHF patients caused by DCM and 220 healthy controls, were involved in the study. The CHF patients were classified as the CSA-CHF group and the non-CSA-CHF group according to the PSG parameters. The rs1739843 polymorphisms of the HSPB7 gene were identified by real-time quantitative polymerase chain reaction.

RESULTS

In the present study, 35.8% of CHF patients caused by DCM had CSR-CSA. Comparison demonstrated that the CSA-CHF group had significantly higher TT genotype and T allele frequencies in the rs1739843 single nucleotide polymorphism (SNP) of the HSPB7 gene. There were no significant differences among the CC genotype distribution of the CSA-CHF group and the non-CSA-CHF group or the control group.

CONCLUSIONS

The rs1739843 polymorphism of the HSPB7 gene might be involved in the pathogenesis of CSR-CSA and CHF subjects caused by DCM in the Chinese Han population. This finding was from a genetic search for the role of the HSPB7 gene in CSR-CSA of CHF patients caused by DCM.

Prevalence and Risk Factors of Sleep Disordered Breathing in Fabry disease: A Prospective Cohort Study

Excessive daytime sleepiness (EDS) is a frequently reported and not well-understood symptom in patients with Fabry disease (FD). Sleep-disordered breathing (SDB) is a possible factor. As deposition of glycosphingolipids in the upper airway muscles is likely, we hypothesized that obstructive sleep apnoea (OSA) is highly prevalent in FD and positively associated with its severity.All patients with FD who are followed in the Fabry cohort of the University Hospital Zurich (n = 62) were asked to participate in this prospective cohort study. Eligible patients were prospectively investigated by assessing their daytime sleepiness using the Epworth Sleepiness Scale (ESS), the severity of FD using the Mainz Severity Score Index (MSSI), and by an ambulatory overnight respiratory polygraphy between November 1, 2013, and January 31, 2015. SDB was defined as an apnea/hypopnea index (AHI) of > 5/h.Fifty-two patients (mean ± SD age 42.8 ± 14.7 years, 33% men, mean ± SD BMI 23.4 ± 3.6 kg/m) with a median (IQR) MSSI of 12 (5-19) were included. Median (IQR) ESS was 6 (2-10) and 7 patients (14%) had an ESS > 10. Thirteen patients (25%) had SDB (78% obstructive sleep apnea, 22% central sleep apnea). In the multivariable analysis, the age was the only statistically significant predictor of SDB (OR 1.11, 95% CI 1.04-1.18, P = 0.001). ESS was associated with depression (P < 0.001) but not AHI nor age.This study shows that SDB, especially obstructive sleep apnea is highly prevalent in patients with Fabry disease. However, EDS in FD seems to be related with depression rather than SDB.ClinicalTrials.gov (identifier: NCT01947634).

Phrenic Nerve Stimulation: Technology and Clinical Applications

Phrenic nerve stimulation is a technique used to reanimate the diaphragm of patients with central nervous system etiologies of respiratory insufficiency. Current clinical indications include congenital central hypoventilation syndrome, spinal cord injury above C4, brain stem injury, and idiopathic severe sleep apnea. Presurgical evaluation ensures proper patient selection by validating the intact circuit from the phrenic nerve through alveolar oxygenation. The procedure involves placing leads around the phrenic nerves bilaterally and attaching these leads to radio receivers in a subcutaneous pocket. The rate and amplitude of the current is adjusted via an external radio transmitter. After implantation, each patient progresses through a conditioning phase that strengthens the diaphragm and progressively provides independence from the mechanical ventilator. Studies indicate that patients and families experience an improved quality of life and are satisfied with the results. Phrenic nerve stimulation provides a safe and effective means for reanimating the diaphragm for certain patients with respiratory insufficiency, providing independence from mechanical ventilation.

The longitudinal effects of persistent periodic breathing on cerebral oxygenation in preterm infants

OBJECTIVES

Periodic breathing is common in preterm infants, but is thought to be benign. The aim of our study was to assess the incidence and impact of periodic breathing on heart rate (HR), oxygen saturation (SpO2), and brain tissue oxygenation index (TOI) over the first six months after term-equivalent age.

STUDY DESIGN

Twenty-four preterm infants (27-36 weeks gestational age) were studied with daytime polysomnography in quiet sleep (QS) and active sleep (AS) and in both the prone and supine positions at 2-4 weeks, 2-3 months, and 5-6 months post-term corrected age. HR, SpO2, and TOI (NIRO-200 spectrophotometer) were recorded. Periodic breathing episodes were defined as greater than or equal to three sequential apneas each lasting ≥3 s.

RESULTS

A total 164 individual episodes of periodic breathing were recorded in 19 infants at 2-4 weeks, 62 in 12 infants at 2-3 months, and 35 in 10 infants at 5-6 months. There was no effect of gestational age on periodic breathing frequency or duration. Falls in HR (-21.9 ± 2.7%) and TOI (-13.1 ± 1.5%) were significantly greater at 2-3 months of age compared to 2-4 weeks of age.

CONCLUSIONS

The majority of preterm infants discharged home without clinical respiratory problems had persistent periodic breathing. Although in most infants periodic breathing was not associated with significant falls in SpO2 or TOI, several infants had significant desaturations and reduced cerebral oxygenation especially during AS. The clinical significance of this on neurodevelopmental outcome is unknown and warrants further investigations.

Prevalence of sleep-disordered breathing in the general population: the HypnoLaus study

BACKGROUND

Sleep-disordered breathing is associated with major morbidity and mortality. However, its prevalence has mainly been selectively studied in populations at risk for sleep-disordered breathing or cardiovascular diseases. Taking into account improvements in recording techniques and new criteria used to define respiratory events, we aimed to assess the prevalence of sleep-disordered breathing and associated clinical features in a large population-based sample.

METHODS

Between Sept 1, 2009, and June 30, 2013, we did a population-based study (HypnoLaus) in Lausanne, Switzerland. We invited a cohort of 3043 consecutive participants of the CoLaus/PsyCoLaus study to take part. Polysomnography data from 2121 people were included in the final analysis. 1024 (48%) participants were men, with a median age of 57 years (IQR 49-68, range 40-85) and mean body-mass index (BMI) of 25·6 kg/m(2) (SD 4·1). Participants underwent complete polysomnographic recordings at home and had extensive phenotyping for diabetes, hypertension, metabolic syndrome, and depression. The primary outcome was prevalence of sleep-disordered breathing, assessed by the apnoea-hypopnoea index.

FINDINGS

The median apnoea-hypopnoea index was 6·9 events per h (IQR 2·7-14·1) in women and 14·9 per h (7·2-27·1) in men. The prevalence of moderate-to-severe sleep-disordered breathing (≥15 events per h) was 23·4% (95% CI 20·9-26·0) in women and 49·7% (46·6-52·8) in men. After multivariable adjustment, the upper quartile for the apnoea-hypopnoea index (>20·6 events per h) was associated independently with the presence of hypertension (odds ratio 1·60, 95% CI 1·14-2·26; p=0·0292 for trend across severity quartiles), diabetes (2·00, 1·05-3·99; p=0·0467), metabolic syndrome (2·80, 1·86-4·29; p<0·0001), and depression (1·92, 1·01-3·64; p=0·0292).

INTERPRETATION

The high prevalence of sleep-disordered breathing recorded in our population-based sample might be attributable to the increased sensitivity of current recording techniques and scoring criteria. These results suggest that sleep-disordered breathing is highly prevalent, with important public health outcomes, and that the definition of the disorder should be revised.

FUNDING

Faculty of Biology and Medicine of Lausanne, Lausanne University Hospital, Swiss National Science Foundation, Leenaards Foundation, GlaxoSmithKline, Ligue Pulmonaire Vaudoise.

Mechanisms and clinical consequences of untreated central sleep apnea in heart failure

Central sleep apnea (CSA) is a highly prevalent, though often unrecognized, comorbidity in patients with heart failure (HF). Data from HF population studies suggest that it may present in 30% to 50% of HF patients. CSA is recognized as an important contributor to the progression of HF and to HF-related morbidity and mortality. Over the past 2 decades, an expanding body of research has begun to shed light on the pathophysiologic mechanisms of CSA. Armed with this growing knowledge base, the sleep, respiratory, and cardiovascular research communities have been working to identify ways to treat CSA in HF with the ultimate goal of improving patient quality of life and clinical outcomes. In this paper, we examine the current state of knowledge about the mechanisms of CSA in HF and review emerging therapies for this disorder.

Clinical heterogeneity of patients with complex sleep apnea syndrome

Background

The definition of complex sleep apnea (CompSAS) encompasses patients with obstructive sleep apnea (OSA) who develop central apnea activity upon restitution of airway patency. Presence of arterial hypertension (HTN), coronary artery disease (CAD) and heart failure (HF) have been proposed as risk factors for CompSAS among OSA patients. Using our database of patients with CompSAS, we examined the prevalence of these risk factors and defined other clinical characteristics of patients with CompSAS.

Methods

Through retrospective search of the database, we examined the medical and clinical characteristics of consecutive patients diagnosed with CompSAS between 11/1/2006 and 6/30/2011 at NorthShore University HealthSystem.

Results

One hundred and fifty patients with CompSAS were identified. Among patients included in the study, 97 (64.7 %) had at least one risk factor for CompSAS, while 53 (35.3 %) did not have any of them. Prevalence of low left ventricular ejection fraction and hypocapnia were low. Therapeutic interventions consisted of several positive airway pressure therapies, mainly adaptive servo ventilation. A hundred and ten patients (73.3 %) complied with recommended therapy and improved clinically.

Conclusions

Although most patients with CompSAS have cardiac comorbidities, about one third of patients do not have any risk factors of CompSAS prior to sleep testing. Further research on factors involved in development of CompSAS will allow for better tailoring of therapy to pathophysiology involved in an individual case.

[Non-invasive ventilation in treatment of adults with chronic respiratory failure]

Non-invasive mechanical ventilation (NIV) is a modern method of chronic respiratory failure (CRF) treatment. With the development of medicine and society known as "western", the number of elderly people, in whom there is overlapping of chronic diseases such as COPD, is growing. In adult population NIV is used in the treatment of neuromuscular diseases such as amyotrophic lateral sclerosis (ALS) or spinal muscular atrophy. The other main indications include restrictive diseases such as kyphoscoliosis, pulmonary diseases with COPD which is the primary indication, and various forms of central apnea syndrome with epidemiologically essential role of obesity hypoventilation syndrome (OHS). In each of those indications, and in different patients, the mode and ventilation intensity may significantly differ. The aim of this review is to disseminate knowledge on the potential role of NIV in adults with CRF. This paper attempts to analyze the available knowledge concerning NIV in adults with CRF. Special attention is paid to the potential pathomechanisms which should become the subject of future research.

Sleep-disordered breathing in multiple sclerosis

BACKGROUND

The objectives of this cross-sectional study were to assess the prevalence and severity of sleep apnea in patients with multiple sclerosis (MS) referred for overnight polysomnography (PSG) and to explore the radiographic and clinical features that might signal risk for undiagnosed sleep apnea.

METHODS

Apnea-hypopnea (AHI) and central apnea indices (CAI) from laboratory-based PSG among 48 patients with MS were compared with those of group A, 84 sleep laboratory-referred patients without MS matched for age, gender, and body mass index; and group B, a separate group of 48 randomly selected, referred patients.

RESULTS

Mean AHI was higher among patients with MS than among control groups A or B (2-way analysis of variance and multiple linear regression, p = 0.0011 and 0.0118, respectively). Median and mean CAI were also increased among patients with MS in comparison to control groups (Wilcoxon signed rank and multiple linear regression, p = 0.0064 and 0.0027, respectively). Among MS patients with available data, those with evidence of brainstem involvement, compared with groups A and B, showed particularly robust differences in AHI (p = 0.0060 and 0.0016) and CAI (p = 0.0215 and <0.0001). In contrast, MS patients without brainstem involvement, compared with groups A and B, showed diminished differences in AHI, and CAI did not significantly differ among groups.

CONCLUSIONS

These data suggest a predisposition for obstructive sleep apnea and accompanying central apneas among patients with MS, particularly among those with brainstem involvement.

Central sleep apnea is a predictor of cardiac readmission in hospitalized patients with systolic heart failure

BACKGROUND

Hospitalized heart failure patients have a high readmission rate. We sought to determine the independent risk due to central sleep apnea (CSA) of readmission in patients with systolic heart failure (SHF).

METHODS AND RESULTS

This was a prospective observational cohort study of hospitalized patients with SHF. Patients underwent sleep studies during their hospitalization and were followed for 6 months to determine their rate of cardiac readmissions; 784 consecutive patients were included; 165 patients had CSA and 139 had no sleep-disordered breathing (SDB); the remainder had obstructive sleep apnea (OSA). The rate ratio for 6 months' cardiac readmissions was 1.53 (95% confidence interval 1.1-2.2; P = .03) in CSA patients compared with no SDB. This rate ratio was adjusted for systolic function, type of cardiomyopathy, age, weight, sex, diabetes, coronary disease, length of stay, admission sodium, creatinine, hemoglobin, blood pressure, and discharge medications. Severe OSA was also an independent predictor of readmissions with an adjusted rate ratio of 1.49 (P = .04).

CONCLUSION

In this first evaluation of the impact of SDB on cardiac readmissions in heart failure, CSA was an independent risk factor for 6 months' cardiac readmissions. The effect size of CSA exceeded that of all known predictors of heart failure readmissions.

Relationship between sleep problems and health-related quality of life among pediatric liver transplant recipients

Among adult liver transplant recipients (LTRs), sleep disturbances and fatigue are common. Sleep problems following pediatric liver transplantation may contribute to daytime fatigue and lower health-related quality of life (HRQOL). The aim of this cross-sectional study was to determine the impact of sleep problems on the HRQOL of pediatric LTRs using validated measures. Participants included 47 LTRs. Mean age of the LTRs was 10.9 ± 4.6 years, and mean time since transplantation was 6.2 ± 3.9 years. The primary indication for transplantation was biliary atresia (51%). According to parent reports, pediatric transplant recipients had symptoms of sleep-disordered breathing, excessive daytime sleepiness, daytime behavior problems, and restless legs; 40.4% of parents and 43.8% of children reported significantly lower total HRQOL for the recipients. Age, time since transplantation, and health status were not significantly related to the quality of life. Hierarchical regression analyses revealed that the sleep-disordered breathing subscale of the Pediatric Sleep Questionnaire accounted for significant variance in parent-proxy reports on the Pediatric Quality of Life (PedsQL) summary scales measuring children's psychosocial health (R(2) = 0.36, P < 0.001), physical health (R(2) = 0.19, P = 0.004), and total HRQOL (R(2) = 0.35, P < 0.001). Also, the sleep-disordered breathing subscale accounted for significant variance in the child self-reported school functioning scale (R(2) = 0.18, P = 0.03). Clinically significant sleep problems were more common among children with low total HRQOL. In conclusion, sleep problems were common in this cohort of pediatric LTRs and predicted significant variance in HRQOL. Prospective larger scale studies are needed to assess factors that contribute to sleep difficulties and low HRQOL in this population. The detection and treatment of significant sleep problems may benefit the HRQOL of pediatric LTRs.

The effects of altitude associated central apnea on the diagnosis and treatment of obstructive sleep apnea: comparative data from three different altitude locations in the mountain west

STUDY OBJECTIVES

This study documents both the incidence and effects of central apnea on diagnosis and treatment of OSA at different altitudes in the Mountain West and substantiates the clinical impression that individuals living at altitude with moderate to severe OSA are significantly more difficult to treat with PAP.

METHODS

Split-night polysomnography was compared between sites for patients with a diagnostic AHI > 15 living at 1421 meters (Site 1; N = 150), at 1808 m (Site 2; N = 150) and at 2165 m (Site 3; N = 142). The quality of PAP titration obtained was rated, based on AASM clinical guidelines, from 1 = optimal to 4 = unacceptable. Patients developing central apneas during PAP therapy (CAI > 5.0) were titrated with an alternative O(2) > CPAP/Bilevel PAP protocol.

RESULTS

The mean number of central apneas in the diagnostic portion of studies was significantly higher (p < 0.01) at Sites 2 (19.26) and 3 (12.36) than at Site 1 (3.11). Mean numbers of central apneas/h developing on treatment with PAP varied from 4.8/h at Site 1, to 9.79/h at Site 2, to 19.25/h at Site 3 (p < 0.001). At Site 1, 10.6% had a central apnea index (CAI) > 5.0, while 22% met this criterion at Site 2 and 38.7% at Site 3 (Site 3 vs Site 1, p = 0.01; Site 2 vs Site 1, p = 0.02). Rated titration quality varied significantly between sites. At Site 1, mean titration quality was 1.437 (SD 0.821); for Site 2, 1.569 (SD 0.96), and for Site 3, 1.772 (SD 1.025). Titration quality at Site 3 was significantly worse than at Site 1 (t = 3.22, p < 0.01) and at Site 2 (t = 2.55, p < 0.02). Repeat titration requirement differed significantly (p = 0.025). Analysis of covariance comparing titration across 3 altitude levels, controlling for age, was significant for the effect of altitude (p = 0.017). Utilizing the alternative O(2) > C-PAP/Bi-PAP protocol in patients with CAI > 5.0 developing on PAP treatment, an overall optimal or good titration (AASM criteria) was attained in 75/79 (95%) of titrated patients.

CONCLUSIONS

This study demonstrates that central apnea becomes significantly more common at increasing altitude in both diagnostic and treatment portions of split-night polysomnography in patients with significant OSA. An apparent exponential increase in the percentage of OSA patients with a CAI > 5.0 occurs with increasing altitude. Altitude associated central apnea has a significant negative effect on the quality of OSA treatment obtained during PAP titration for patients living at the altitudes addressed in this study.

Influence of central apnea in the preterm newborn with gastroesophageal reflux disease

BACKGROUND

Gastroesophageal reflux occurs frequently in newborns. A relationship has been suspected between reflux and apnea of prematurity. The objective of this study is to determine this relationship, owing to the fact that premature newborns have immaturity of structures, especially esophageal smooth muscle.

METHODS

We conducted a longitudinal, analytical, comparative, and observational case/control study. The study was carried out at the Neonatal Intensive Care Unit and in the Gastrointestinal Physiology Department of the Hospital Español (Mexico City) between January 2002 and December 2004.

RESULTS

We included 22 patients: 11 females and 11 males. Mean age was 17.8 ± 8.4 days. Premature newborns represented 72.72% (n = 16). Mean gestational age was 33.1 ± 4.18 weeks. All cases were suspicious for central apnea except for three patients with a mixed cause of apnea. All were submitted to a 24-h pHmetry and a simultaneous polysomnography. Polysomnography was positive in 59% (n = 13) and pHmetry was positive in 50% (n = 11). Prematurity had a strong positive relation with central apnea of the newborn (odds ratio: 15 (p = 0.0154)). Odds ratio for association of central apnea and gastroesophageal reflux was 3.2 (p = 0.2037).

CONCLUSIONS

We demonstrate that central apnea in the premature newborn is not a cause of gastroesophageal reflux. However, these patients are more likely to have gastroesophageal reflux in the first days of extrauterine life. It is recommended to exclude pathological gastroesophageal reflux when the newborn presents a clinical scenario compatible with central apnea.

Central apnoeas in infants with bronchiolitis admitted to the paediatric intensive care unit

AIM

To further characterize apnoea(s) complicating bronchiolitis because of respiratory syncytial virus (RSV), to describe the incidence of this complication and identify possible risk factors for apnoea(s) and its development.

METHODS

The files of infants admitted to the paediatric intensive care unit (PICU) for RSV bronchiolitis during three bronchiolitis seasons (2004-2007) were reviewed for demographic, clinical and laboratory parameters. Parameters were compared between patients with and without apnoeas.

RESULTS

Seventy-nine patients met the study criteria: 43 were admitted to the PICU for central apnoeas and the remainder for respiratory distress or failure. The percentage of infants admitted for apnoea increased during the study period (28.6 to 77.1%, p = 0.004). The overall prevalence of apnoea in this population was 4.3%. Possible risk factors for apnoea(s) were younger age (1.3 vs. 4.3 months, p = 0.002), lower admission weight (3.3 vs. 5 kg, p < 0.001), lower gestational age (35.8 vs. 37.8 weeks, p = 0.01), admission from the emergency room (50% vs. 9.1%, p < 0.001) and lack of hyperthermia (p < 0.001). Respiratory acidosis was found to be a protective factor on logistic regression analysis.

CONCLUSION

The prevalence of apnoea in infants admitted to the PICU for RSV bronchiolitis in our centre may be increasing. Preterm, younger infants with no fever are at relatively high risk of apnoea at presentation, while older infants with fever are at lower risk.

Obstructive sleep apnea is more common than central sleep apnea in methadone maintenance patients with subjective sleep complaints

OBJECTIVES

Opioid-dependent patients treated with methadone have subjective sleep complaints and disrupted sleep on polysomnography (PSG). Previous studies of sleep-disordered breathing (SDB) in this population have focused on central sleep apnea (CSA). Our objectives were to: (1) characterize obstructive sleep apnea (OSA) and CSA in patients in methadone maintenance treatment (MMT) for opioid dependence; (2) examine factors associated with SDB in this population; and (3) investigate whether SDB was related to severity of subjective sleep complaints in MMT patients with subjective sleep disturbances.

METHODS

We analyzed OSA and CSA from one night of home PSG in 71 patients who were in MMT for at least 3 months and had a Pittsburgh Sleep Quality Inventory (PSQI) score >5.

RESULTS

OSA (defined as obstructive apnea-hypopnea index (OAHI) > or = 5) was observed in 35.2% of our sample. OSA was associated with higher body mass index, longer duration in MMT, and non-Caucasian race. CSA (defined as central apnea index (CAI) > or = 5) was observed in 14.1% of the sample. CSA was not associated with methadone dose or concomitant drug use. Subjective sleep disturbance measured with the PSQI was not related to OSA or CSA.

CONCLUSIONS

SDB was common in this sample of MMT patients and OSA was more common than CSA. Given the lack of association between presence of SDB and severity of subjective sleep difficulties, factors other than sleep apnea must account for complaints of disturbed sleep in this population.

Reduction of central sleep apnea in heart failure patients with beta-blockers therapy

BACKGROUND

Sleep apneas are frequent in patients with heart failure (HF). Estimate of the pre-beta blocker age (BB) point out to 45% of central apneas in these patients.

OBJECTIVE

Assess the influence of BB in central apneas and their interference in the quality of sleep and life of patients with heart failure.

METHODS

65 patients with heart failure underwent diagnostic polysomnography. Polysomnography have been assessed according to the use or not of BB. On the day of examination, the patients answered the Minnesota questionnaire for quality of life with HF. After 6 and 12 months from the polysomnography date, all patients were contacted by phone, in order to repeat the Minnesota questionnaire.

RESULTS

The prevalence of sleep apnea (IAH > 15/h) hit 46.1% in the total population, however, central sleep apnea was identified in 18.4% of patients. The use of BB, in a multivariate analysis, was the only predictor of a minor index of central apnea and hypopnea (IAH) (p=0.002), greater saturation (p=0.02) and smaller average desaturation of oxygen (p=0.03). Additionally, the use of BB could predict a better quality of life after 6 and 12 months (p=0.002 and 0.001 respectively) and a smaller number admissions in these periods (p=0.001 and p=0.05 respectively).

CONCLUSION

The use BB reduced the rate of central sleep apnea in total population, if we compare to literature data. Additionally, the BB improved parameters of quality of sleep and life of patients with heart failure.

Sleep-disordered breathing in patients with Parkinson's disease

INTRODUCTION

There are limited studies reporting the frequency of sleep-disordered breathing (SDB) in Parkinson's disease (PD), and the figures quoted are variable, ranging from 2.5 to 66 percent. This study aimed to determine the prevalence and types of SBD in PD patients attending the Universiti Kebangsaan Malaysia Medical Centre neurology clinic, and the correlation between the subjective sleep symptoms using the Parkinson's disease sleep scale (PDSS) and the objective measurements using polysomnography (PSG).

METHODS

This was a cross-sectional study involving 46 PD patients over a period of six months. The patients' demographic data, Hoehn and Yahr staging and PDSS scores were collected. The patients were then subjected to overnight PSG using the Somnomedic system.

RESULTS

There were 27 male and 19 female patients with a mean age of 64.0+/-9.7 years. 29 were Chinese, 15 Malay and 2 Indian. The mean duration of illness was 5.8+/-4.3 years. The mean PDSS score was 120.3+/-13.5. SDB was found in 54.6 percent of the patients (apnoeahypopnoea index [AHI] 5 and above), with 27.3 percent having moderate and severe SDB (AHI 15 and above). The median AHI was 6.7 (range 0-40.4). The prevalence of SDB in PD patients based on the AHI cutoffs were 27.3 percent for mild, 18.2 percent for moderate and 9.1 percent for severe. There were statistically significant positive correlations between the AHI and the neck circumference and between the AHI and the waist-hip ratio. There was no significant correlation between the AHI and PDSS, or the AHI and disease severity.

CONCLUSION

There was a high prevalence of SBD in our PD patients, which was comparable to other studies. Obstructive sleep apnoea was the dominant type of SBD. There was no correlation between the subjective sleep symptoms using the PDSS and the objective measurements using PSG.

Marked reduction in obstructive sleep apnea severity in slow wave sleep

INTRODUCTION

Obstructive sleep apnea (OSA) is widely accepted to improve during slow wave sleep (SWS) compared to lighter stages of NREM sleep. However, supporting data to establish the magnitude and prevalence of this effect is lacking. Consequently, we examined this phenomenon, controlling for posture, in a large group of patients investigated for OSA at an academic clinical sleep service.

METHODS

A detailed retrospective analysis was conducted on data obtained from each 30-sec epoch of sleep in 253 consecutive full-night diagnostic polysomnography studies performed over a 3-month period. Respiratory and arousal event rates were calculated within each stage of sleep, in the supine and lateral postures, and across the whole night, with OSA patients classified on the basis of an overall apnea-hypopnea index (AHI) > or =15 events/h. Central sleep apnea (CSA) patients were defined by a central apnea index > 5/h. Sleep latency and time, and respiratory and arousal event rates in OSA, CSA, and non-OSA patients were compared between sleep stages and postures using linear mixed model analysis. The numbers of patients achieving reduced event rates in SWS and in the lateral posture were also examined.

RESULTS

There were 171 patients with OSA, 14 with CSA, and 68 non-OSA patients. OSA patients took significantly longer to achieve slow wave and REM sleep (p < 0.001) than non-OSA patients and had less stage 4 sleep (p = 0.037). There were striking improvements in AHI and arousal index (Al) from stage 1 to 4 NREM sleep (p <0.001), with intermediate levels in REM sleep. AHI and Al were also markedly reduced in lateral versus supine sleep in all sleep stages (p < 0.001), with an effect size comparable to that of the slow wave sleep effect. The majority of OSA patients achieved low respiratory event rates in SWS. Eighty-two percent of patients achieved an AHI <15 and 57% < 5 events/hour during stage 4 sleep.

CONCLUSION

Although OSA patients demonstrate both a delayed and reduced proportion of SWS compared to non-OSA subjects, once they achieved SWS, AHI, and Al markedly improved in most patients.

Is there a clear link between overweight/obesity and sleep disordered breathing in children?

The proportion of children who are overweight or obese has risen steadily in recent decades and approaches a quarter of all children in Western countries. This global epidemic of excess weight and adiposity in humans is associated with increased morbidity and mortality, especially related to diabetes and poor cardiovascular health. It would appear that obesity is also generally accepted to be an important risk factor in the development of sleep disordered breathing (SDB), in children as well as adults. The article, "The prevalence, anatomical correlates and treatment of sleep-disordered breathing in obese children and adolescents", by Verhulst et al., also in this issue, reviews evidence supporting the view that obese children are at higher risk of developing SDB. We believe, however, that the available studies do not support a straightforward association of overweight or obesity with increased prevalence of SDB. Rather, the available data is clearly equivocal mainly due to methodological differences between the previous studies. This review nonetheless examines the factors which may modulate the relationship between overweight or obesity and prevalence of SDB, particularly ethnicity and age.

Sleep apnea syndrome: implications on cardiovascular diseases

Global risk assessment is the standard of care for coronary artery disease management. In this setting, sleep apnea syndrome, which includes obstructive sleep apnea and central sleep apnea, is being increasingly recognized as a potentially modifiable risk factor for coronary artery disease. Emerging evidence points toward a cause and effect relationship between sleep apnea syndrome and medical conditions like insulin resistance, hypertension, heart failure, and myocardial ischemia. The effects of sleep apnea on coronary artery disease can be independent of many traditional risk factors. Continuous positive airway pressure has been shown to decrease inflammatory markers that are elevated in sleep apnea syndrome. Well-designed randomized controlled clinical trials are needed to better establish the role of sleep apnea in the genesis and progression of coronary artery disease.

Sleep-disordered breathing in children

Pediatric Sleep Disordered Breathing (SDB) is often associated with behavioral problems, poor school performance, decreased quality of life and increased healthcare utilization. Adenotonsillectomy (T&A) leads to resolution of SDB in over 80% of children and results in behavioral improvement and better quality of life. Obese children, as well as those afflicted with craniofacial, genetic or neuromuscular disorders, are at greater risk for SDB than healthy children. This report highlights the need to recognize and treat SDB in children.

The current prevalence of sleep disordered breathing in congestive heart failure patients treated with beta-blockers

STUDY OBJECTIVES

Although sleep disordered breathing is thought to be common in patients with systolic heart failure, prior studies are difficult to interpret due to a variety of factors including small sample sizes, referral bias to sleep laboratories among participants, lack of modern medical therapy for congestive heart failure, and the failure to use modern techniques to assess breathing such as nasal pressure. Our objective was to determine the current prevalence of sleep disordered breathing in a state-of-the-art congestive heart failure clinic.

METHODS

We conducted a prospective study of consecutive patients who visited our heart failure clinic to assess the prevalence of sleep apnea in all eligible patients on maximal medical therapy. We used 4-channel recording equipment and modified Chicago criteria for scoring respiratory events (using heart rate response as a surrogate for arousal from sleep).

RESULTS

We observed that among the 108 participants, 61% had some form of sleep disordered breathing (31% central apnea with Cheyne Stokes respiration and 30% obstructive sleep apnea). Sleep disordered breathing was significantly associated with atrial fibrillation (OR = 11.56, p = 0.02) and worse functional heart failure class (OR = 2.77, p = 0.02), after adjusting for male sex, age over 60 years, body mass index, and left ventricular ejection fraction.

CONCLUSIONS

We conclude that both obstructive and central sleep apnea remain common in congestive heart failure patients despite advances in medical therapy, and that the previously reported high prevalence values are unlikely to be explained by referral bias or participation bias in prior studies. These data have important clinical implications for practitioners providing CHE therapy.

Influence of cardiac resynchronisation therapy on different types of sleep disordered breathing

AIMS

This study investigates the influence of cardiac resynchronisation therapy (CRT) on sleep disordered breathing (SDB) in patients with severe heart failure (HF).

METHODS AND RESULTS

Seventy-seven patients with HF (19 females; 62.6+/-10 years) eligible for CRT were screened for presence, type, and severity of SDB before and after CRT initiation (5.3+/-3 months) using cardiorespiratory polygraphy. NYHA class, frequency of nycturia, cardiopulmonary exercise, 6-minute walking test results, and echocardiography parameters were obtained at baseline and follow-up. Central sleep apnoea (CSA) was documented in 36 (47%), obstructive sleep apnoea (OSA) in 26 (34%), and no SDB in 15 (19%) patients. CRT improved clinical and haemodynamic parameters. SDB parameters improved in CSA patients only (apnoea hypopnoea index: 31.2+/-15.5 to 17.3+/-13.7/h, p<0.001; SaO2min: 81.8+/-6.6 to 84.8+/-3.3%, p=0.02, desaturation: 6.5+/-2.3 to 5.5+/-0.8%, p=0.004). Daytime capillary pCO2 was significantly lower in CSA patients compared to those without SDB with a trend towards increase with CRT (35.5+/-4.2 to 37.9+/-5.7 mm Hg, ns). After classifying short term clinical and haemodynamic CRT effects, improved SDB parameters in CSA occurred in responders only.

CONCLUSIONS

In patients with severe HF eligible for CRT, CSA is common and can be influenced by CRT, this improvement depends on good clinical and haemodynamic response to CRT.

Sleep-disordered breathing and cardiovascular risk

Sleep-disordered breathing, broadly characterized by obstructive sleep apnea (OSA) and central sleep apnea (CSA), is an increasingly recognized public health burden. OSA, consisting of apneas or hypopneas associated with respiratory efforts in the face of upper airway narrowing or collapse, is a common disorder that can be effectively treated with continuous positive airway pressure (CPAP). OSA not only results in daytime sleepiness and impaired executive function, but also has been implicated as a possible cause of systemic disease, particularly of the cardiovascular system. CSA, which may coexist with OSA, has gained attention because of the association of Cheyne-Stokes respiration with an ever-increasing prevalence of heart failure in an aging population. This article reviews some of the extensive literature on pathophysiologic mechanisms as they may relate to the development of cardiac and vascular disease and examine the evidence suggesting OSA as a specific cause of certain cardiovascular conditions. Available evidence regarding the implications of CSA in the context of heart failure is discussed.

High Prevalence of Sleep Apnea Syndrome in Patients With Long-Term Pacing

Background— Cardiovascular diseases leading to pacemaker implantations are suspected of being associated with a high rate of undiagnosed sleep apnea syndrome (SAS). We sought to determine the prevalence and consequences of SAS in pacemaker patients according to pacing indications: heart failure, symptomatic diurnal bradycardia, and atrioventricular block.

Methods and Results— Ninety-eight consecutive patients (mean age, 64±8 years) not known to have sleep apnea were included; 29 patients were paced for dilated cardiomyopathy (29%), 33 for high-degree atrioventricular block (34%), and 36 for sinus node disease (37%). All underwent Epworth Sleepiness Scale assessment and polysomnography with the pacemaker programmed to right ventricular DDI pacing mode (lower pacing rate, 50 pulses per minute). SAS was defined as an apnea-hypopnea index ≥10/h. Mean Epworth Sleepiness Scale was in the normal range (7±4), although 13 patients (25%) had an abnormal score >11/h. Fifty-seven patients (59%) had SAS; of these, 21 (21.4%) had a severe SAS (apnea-hypopnea index >30/h). In patients with heart failure, 50% presented with SAS (mean apnea-hypopnea index, 11±7) compared with 68% of patients with atrioventricular block (mean apnea-hypopnea index, 24±29) and 58% with sinus node disease (mean apnea-hypopnea index, 19±23).

Conclusions— In paced patients, there is an excessively high prevalence of undiagnosed SAS (59%). Whether treating SAS would have changed the need for pacing is unknown. Treatment effects should be further evaluated particularly because these patients are less symptomatic than typical SAS patients. In any case, SAS should be systematically searched for in paced patients owing to potential detrimental effects on their cardiovascular evolution.

Sleep apnea in the elderly: a specific entity?

Sleep apnea is highly prevalent in subjects after age 60, and affects older men and women similarly. Central apneas are often observed in addition to obstructive and mixed events. Pathogenesis of obstructive and central events during sleep in the elderly can be attributed to an amplification of well-established causes of sleep-disordered breathing (SDB) in younger adults. As in middle-aged adults, sleep-related complaints, cardiovascular diseases, depression and traffic accidents should prompt an evaluation by a sleep specialist. However, secondary enuresis and nocturia, cognitive impairment, ophthalmic conditions and repeated falls may be the main complaint in elderly subjects. Sleep studies in the elderly should systematically include reliable means to detect central apneas and periodic leg movements. Untreated SDB in the elderly appears to have a lesser impact on mortality than in middle-aged adults. However, the typical morbidity associated with the disorder in younger adults is observed in the elderly. Elderly symptomatic SDB patients tolerate CPAP no differently than younger patients and should be effectively treated. In conclusion, whether sleep apnea in the elderly represents a specific entity or the same disease as in younger subjects, with some distinctive features, is still unclear. Further research, in particular focusing on the impact of age on SDB outcomes, is needed.

[Complex sleep apnea syndrome]

Some patients with obstructive sleep apnea (OSA) develop persistent central sleep apnea activity when started on continuous positive airway pressure (CPAP). This recently recognized syndrome, complex sleep apnea syndrome (CompSAS), is thought to be due to dysfunction of the respiratory center in a setting of an obstructive sleep apnea. We present the current knowledge on epidemiology, pathophysiology, and treatment options in CompSAS. We review the current literature on CompSAS, and present our own data on this interesting condition.