Compliance with and effectiveness of adaptive servoventilation versus continuous positive airway pressure in the treatment of Cheyne-Stokes respiration in heart failure over a six month period

Chronic Effects of Adaptive Servo-Ventilation Therapy on Mortality and the Urgent Rehospitalization Rate in Patients Experiencing Recurrent Admissions for Heart Failure - A Multicenter Prospective Observational Study (SAVIOR-L)

BACKGROUND

This study investigated whether the chronic use of adaptive servo-ventilation (ASV) reduces all-cause mortality and the rate of urgent rehospitalization in patients with heart failure (HF).Methods and Results: This multicenter prospective observational study enrolled patients hospitalized for HF in Japan between 2019 and 2020 who were treated either with or without ASV therapy. Of 845 patients, 110 (13%) received chronic ASV at hospital discharge. The primary outcome was a composite of all-cause death and urgent rehospitalization for HF, and was observed in 272 patients over a 1-year follow-up. Following 1:3 sequential propensity score matching, 384 patients were included in the subsequent analysis. The median time to the primary outcome was significantly shorter in the ASV than in non-ASV group (19.7 vs. 34.4 weeks; P=0.013). In contrast, there was no significant difference in the all-cause mortality event-free rate between the 2 groups.

CONCLUSIONS

Chronic use of ASV did not impact all-cause mortality in patients experiencing recurrent admissions for HF.

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

BACKGROUND

Sleep-disordered breathing (SDB) is a common comorbidity in patients with heart failure (HF) and is associated with worse prognosis.

OBJECTIVES

This study evaluated the effects of adaptive servo-ventilation (ASV) on morbidity and mortality in a large heterogeneous population of HF patients with different etiologies/phenotypes.

METHODS

Consecutive HF patients with predominant central sleep apnea (± obstructive sleep apnea) indicated for ASV were included; the control group included patients who refused or stopped ASV before three months follow-up. Six homogenous clusters were determined using the latent class analysis (LCA) method. The primary endpoint was time to composite first event (all-cause death, lifesaving cardiovascular intervention, or unplanned hospitalization for worsening of chronic HF).

RESULTS

Of 503 patients at baseline, 324 underwent 2-year follow-up. Compared to control group, 2-year primary endpoint event-free survival was significantly greater in patients in ASV group only in univariable analysis (1.67, 95% [1.12-2.49]; p = 0.01). Secondary endpoints, event-free of cardiovascular death or heart failure-related hospitalization and all-cause death or all-cause hospitalization were positively impacted by ASV (univariate and multivariable analysis). LCA identified two groups, with preserved and mid-range left ventricular ejection fraction (LVEF) and severe hypoxia, in whom ASV increase prognosis benefit.

CONCLUSIONS

Patients with HF and SDB are a highly heterogeneous group identified using LCA. Systematic deep phenotyping is essential to ensure that ASV is prescribed to those benefit from therapy, as ASV use in patients with severe hypoxic burden and those with HFpEF was associated with a significant reduction in cardiovascular events and mortality.

CLINICAL TRIAL REGISTRATION

https://clinicaltrials.gov/ct2/show/NCT01831128.

Experience With Adaptive Servo-Ventilation Among Veterans in the Post-SERVE-HF Era

Background

The sleep medicine community has struggled to identify the ideal role for adaptive servo-ventilation (ASV) therapy following a study that found increased mortality in patients with central sleep apnea (CSA) and heart failure with reduced ejection fraction who used ASV therapy. We aimed to identify characteristics of patients who benefit from ASV therapy.

Methods

We performed a record review of all patients treated with ASV therapy at the Hampton Veterans Affairs Medical Center in Virginia from January 1, 2015, to April 30, 2020. Clinical and polysomnographic characteristics of patients adherent to therapy were compared with those that were not adherent.

Results

Our cohort of 31 patients was entirely male with a mean age of 67.2 years, body mass index of 34.0, and Epworth Sleepiness Scale score of 10.9. Primary CSA was initially diagnosed in 3 patients (10%), comorbid obstructive sleep apnea (OSA) and CSA in 9 (29%), and primary OSA in 19 (61%). Seventeen patients (55%) met minimal adherence criteria with ASV therapy. The obstructive apnea-hypopnea index (AHI), as a proportion of the total pretreatment AHI, was higher in adherent patients (81.5%) vs nonadherent patients (46.7%) (P = .02). The median residual AHI was lower in the adherent group, both as absolute values (1.7 vs 4.7 events/h; P = .004) and as a percentage of the pretreatment AHI (3.1% vs 10.2%; P = .002).

Conclusions

Patients using ASV devices regularly have a larger component of obstructive sleep-disordered breathing and obtain greater objective benefit from ASV than those that do not. This understanding may help to identify patients that will most benefit from this debated form of therapy.

Effect of adaptive servo ventilation on central sleep apnea and sleep structure in systolic heart failure patients: polysomnography data from the SERVE-HF major sub study

This SERVE-HF (Treatment of Predominant Central Sleep Apnea by Adaptive Servo Ventilation in Patients With Heart Failure) sub study analysis evaluated polysomnography (PSG) data in patients with heart failure with reduced ejection fraction (HFrEF) and predominant central sleep apnea (CSA) randomised to guideline-based medical therapy, with or without adaptive servo ventilation (ASV). Patients underwent full overnight PSG at baseline and at 12 months. All PSG recordings were analysed by a core laboratory. Only data for patients with baseline and 3- or 12-month values were included. The sub study included 312 patients; the number with available PSG data differed for each variable (94-103 in the control group, 77-99 in the ASV group). After 12 months, baseline-adjusted respiratory measures were significantly better in the ASV group versus control. Although some between-group differences in sleep measures were seen at 12 months (e.g., better sleep efficiency in the ASV group), these were unlikely to be clinically significant. The number of periodic leg movements during sleep (PLMS) increased in the ASV group (p = 0.039). At 12 months, the respiratory arousal index was significantly lower in the ASV versus control group (p < 0.001), whilst the PLMS-related arousal index was significantly higher in the ASV group (p = 0.04 versus control). ASV attenuated the respiratory variables characterising sleep apnea in patients with HFrEF and predominant CSA in SERVE-HF. Sleep quality improvements during ASV therapy were small and unlikely to be clinically significant. The increase in PLMS and PLMS-related arousals during ASV warrants further investigation, particularly relating to their potential association with increased cardiovascular risk.

Non-invasive positive pressure ventilation for central sleep apnoea in adults

BACKGROUND

Central sleep apnoea (CSA) is characterised by abnormal patterns of ventilation during sleep due to a dysfunctional drive to breathe. Consequently, people with CSA may present poor sleep quality, sleep fragmentation, inattention, fatigue, daytime sleepiness, and reduced quality of life.

OBJECTIVES

To assess the effectiveness and safety of non-invasive positive pressure ventilation (NIPV) for the treatment of adults with CSA.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and Scopus on 6 September 2021. We applied no restrictions on language of publication. We also searched clinical trials registries for ongoing and unpublished studies, and scanned the reference lists of included studies to identify additional studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) reported in full text, those published as abstract only, and unpublished data.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies for inclusion, extracted data, and assessed risk of bias of the included studies using the Cochrane risk of bias tool version 1.0, and the certainty of the evidence using the GRADE approach. In the case of disagreement, a third review author was consulted.

MAIN RESULTS

We included 15 RCTs with a total of 1936 participants, ranging from 10 to 1325 participants. All studies had important methodological limitations. We assessed most studies (11 studies) as at high risk of bias for at least one domain, and all studies as at unclear risk of bias for at least two domains. The trials included participants aged > 18 years old, of which 70% to 100% were men, who were followed from one week to 60 months. The included studies assessed the effects of different modes of NIPV and CSA. Most participants had CSA associated with chronic heart failure. Because CSA encompasses a variety of causes and underlying clinical conditions, data were carefully analysed, and different conditions and populations were not pooled. The findings for the primary outcomes for the seven evaluated comparisons are presented below.  Continuous positive airway pressure (CPAP) plus best supportive care versus best supportive care in CSA associated with chronic heart failure In the short term, CPAP plus best supportive care may reduce central apnoea hypopnoea index (AHI) (mean difference (MD) -14.60, 95% confidence interval (CI) -20.11 to -9.09; 1 study; 205 participants). However, CPAP plus best supportive care may result in little to no difference in cardiovascular mortality compared to best supportive care alone. The evidence for the effect of CPAP plus best supportive care on all-cause mortality is very uncertain. No adverse effects were observed with CPAP, and the results for adverse events in the best supportive care group were not reported. Adaptive servo ventilation (ASV) versus CPAP in CSA associated with chronic heart failure The evidence is very uncertain about the effect of ASV versus CPAP on quality of life evaluated in both the short and medium term. Data on adverse events were not reported, and it is not clear whether data were sought but not found. ASV versus bilevel ventilation in CSA associated with chronic heart failure In the short term, ASV may result in little to no difference in central AHI. No adverse events were detected with ASV, and the results for adverse events in the bilevel ventilation group were not reported. ASV plus best supportive care versus best supportive care in CSA associated with chronic heart failure In the medium term, ASV plus best supportive care may reduce AHI compared to best supportive care alone (MD -20.30, 95% CI -28.75 to -11.85; 1 study; 30 participants). In the long term, ASV plus best supportive care likely increases cardiovascular mortality compared to best supportive care (risk ratio (RR) 1.25, 95% CI 1.04, 1.49; 1 study; 1325 participants). The evidence suggests that ASV plus best supportive care may result in little to no difference in quality of life in the short, medium, and long term, and in all-cause mortality in the medium and long term. Data on adverse events were evaluated but not reported. ASV plus best supportive care versus best supportive care in CSA with acute heart failure with preserved ejection fraction Only adverse events were reported for this comparison, and no adverse events were recorded in either group. ASV versus CPAP maintenance in CPAP-induced CSA In the short term, ASV may slightly reduce central AHI (MD -4.10, 95% CI -6.67 to -1.53; 1 study; 60 participants), but may result in little to no difference in quality of life. Data on adverse events were not reported, and it is not clear whether data were sought but not found. ASV versus bilevel ventilation in CPAP-induced CSA In the short term, ASV may slightly reduce central AHI (MD -8.70, 95% CI -11.42 to -5.98; 1 study; 30 participants) compared to bilevel ventilation. Data on adverse events were not reported, and it is not clear whether data were sought but not found.

AUTHORS' CONCLUSIONS

CPAP plus best supportive care may reduce central AHI in people with CSA associated with chronic heart failure compared to best supportive care alone. Although ASV plus best supportive care may reduce AHI in people with CSA associated with chronic heart failure, it likely increases cardiovascular mortality in these individuals. In people with CPAP-induced CSA, ASV may slightly reduce central AHI compared to bilevel ventilation and to CPAP. In the absence of data showing a favourable impact on meaningful patient-centred outcomes and defining clinically important differences in outcomes in CSA patients, these findings need to be interpreted with caution. Considering the level of certainty of the available evidence and the heterogeneity of participants with CSA, we could draw no definitive conclusions, and further high-quality trials focusing on patient-centred outcomes, such as quality of life, quality of sleep, and longer-term survival, are needed to determine whether one mode of NIPV is better than another or than best supportive care for any particular CSA patient group.

Elevated serum matrix metalloproteinase-2 levels in heart failure patients with reduced ejection fraction and Cheyne-Stokes respiration

STUDY OBJECTIVES

Cheyne-Stokes respiration (CSR), a kind of central sleep apnea (CSA), is referred to as a poor prognostic factor in heart failure patients with reduced ejection fraction (HFrEF). Matrix metalloproteinase (MMP) and B-type natriuretic peptide (BNP) play important roles in HFrEF patients and are markers of poor prognosis. However, there is no literature mentioning the changes in MMP and BNP in HFrEF patients with CSR.

METHODS

From June 2018 to June 2019, 41 adult patients with stable heart failure and left ventricular ejection fraction (LVEF) <50% were enrolled from the cardiology clinic. After history taking and medication review to exclude possible central nervous system or medication related CSA, an overnight polysomnography study was performed, and CSR was identified. The morning serum MMP-2, MMP-9 and BNP levels were determined using enzyme-linked immunosorbent assay and fluorescence immunoassay techniques. A positive airway pressure (PAP) device was applied to 7 patients for 3 months.

RESULTS

The serum MMP-2 and BNP levels were significantly higher in HFrEF patients with CSR than in patients without CSR. In addition, elevated serum MMP-2 levels correlated well with the severity of sleep apnea and intermittent hypoxia, which were represented as the apnea-hypopnea index and the oxygen-desaturation index. No positive correlation was found between those markers and LVEF. Finally, the treatment of sleep apnea with CPAP for 3 months tended to reduce the elevated serum MMP-2 levels.

CONCLUSIONS

Higher serum MMP-2 and BNP levels were found in HFrEF patients with CSR. Elevated MMP-2 levels were correlated with the severity of sleep apnea and intermittent hypoxia.

Treatment of Cheyne-Stokes Respiration in Heart Failure with Adaptive Servo-Ventilation: An Integrative Model

The SERVE-HF (Treatment of Predominant Central Sleep Apnea by Adaptive Servo Ventilation in Patients with Heart Failure) multicenter trial found a small but significant increase in all-cause and cardiovascular mortality in patients assigned to adaptive servo-ventilation (ASV) versus guideline-based medical treatment. To better understand the physiological underpinnings of this clinical outcome, we employ an integrative computer model to simulate congestive heart failure with Cheyne-Stokes respiration (CHF-CSR) in subjects with a broad spectrum of underlying pathogenetic mechanisms, as well as to determine the in silico changes in cardiopulmonary and autonomic physiology resulting from ASV. Our simulation results demonstrate that while the elimination of CSR through ASV can partially restore cardiorespiratory and autonomic physiology toward normality in the vast majority of CHF phenotypes, the degree of restoration can be highly variable, depending on the combination of CHF mechanisms in play. The group with the lowest left ventricular ejection fraction (LVEF) appears to be most vulnerable to the potentially adverse effects of ASV, but the level of pulmonary capillary wedge pressure (PCWP) plays an important role in determining the nature of these effects.

Central sleep apnea treatment in patients with heart failure with reduced ejection fraction: a network meta-analysis

PURPOSE

Adaptive servo-ventilation (ASV) is contraindicated for the treatment of central sleep apnea (CSA) in patients with heart failure with reduced ejection fraction (HFrEF), limiting treatment options. Though continuous positive airway pressure (CPAP), bi-level PAP with back-up rate (BPAP-BUR), and transvenous phrenic nerve stimulation (TPNS) are alternatives, not much is known about their comparative efficacies, which formed the basis of conducting this network meta-analysis. We sought to analyze their comparative effectiveness in reducing apnea hypopnea index (AHI). Additionally, we also studied their comparative effectiveness on subjective daytime sleepiness as assessed by Epworth sleepiness score (ESS).

METHODS

Randomized controlled trials (RCTs) from PubMed were analyzed in a network meta-analysis and relative superiority was computed based on P-score ranking and Hasse diagrams.

RESULTS

Network meta-analysis based on 8 RCTs showed that when compared to guideline-directed medical therapy (GDMT-used as a common comparator across trials), reduction in AHI by ASV (- 26.05 [- 38.80; - 13.31]), TPNS (- 24.90 [- 42.88; - 6.92]), BPAP-BUR (- 20.36 [- 36.47; - 4.25]), and CPAP (- 16.01 [- 25.42; - 6.60]) were statistically significant but not between the interventions. Based on 6 RCTs of all the interventions, only TPNS showed a statistically significant decrease in ESS (- 3.70 (- 5.58; - 1.82)) when compared to GDMT, while also showing significant differences when compared with ASV (- 3.20 (- 5.86; - 0.54)), BPAP-BUR (- 4.00 (- 7.33; - 0.68)), and CPAP (- 4.45 (- 7.75; - 1.14)). Ranking of treatments based on Hasse diagram, accounting for both AHI and ESS as outcomes for relative hierarchy showed relative superiority of both ASV and TPNS over BPAP-BUR and CPAP.

CONCLUSIONS

Results indicated relative superiority of TPNS and ASV to BPAP-BUR and CPAP in their effects on AHI and ESS.

Therapeutic value of treating central sleep apnea by adaptive servo-ventilation in patients with heart failure: A systematic review and meta-analysis

BACKGROUND

Despite the efficacy of adaptive servo-ventilation (ASV) in suppressing central sleep apnea (CSA), its impact on long-term outcomes is debatable. We aim to identify subjects with specific features who might benefit from ASV therapy.

METHODS

Randomized clinical trials and comparative observational studies investigating the effects of ASV on cardiovascular (CV) and all-cause mortality and major adverse cardiovascular events (MACEs) in CSA patients were searched from PubMed, EMBASE, Cochrane library and Web of Science. Eligible studies were identified with relative risks (RR) of death and MACEs compared between patients treated by ASV and usual care.

RESULTS

A total of eight studies (three randomized controlled trials and five observational studies) including 2208 participants were selected for analysis. All-cause and CV mortality were not significantly reduced by ASV. Patients with nadir nocturnal saturation ≤ 80% (mean value) had lower risk of MACEs by ASV treatment compared with by usual care (RR, 0.18; p < 0.001). Patients with severe heart failure (HF), defined as left ventricular ejection fraction (LVEF) ≤ 33% (mean value), or HF of New York Heart Association (NYHA) classification of III/IV, did not have reduced risk of MACEs post ASV therapy. However, subjects with LVEF > 33% (RR, 0.35; p < 0.001) or NYHA Ⅰ/Ⅱ (RR, 0.35; p < 0.001) had significantly lower risk of MACEs by using ASV than by usual care.

CONCLUSIONS

Although ASV appears to not reduce CV and all-cause death for HF patients with extremely low LVEF, those with profound CSA associated hypoxemia or less severe HF still benefit from ASV therapy.

Patterns of adaptive servo-ventilation settings in a real-life multicenter study: pay attention to volume! : Adaptive servo-ventilation settings in real-life conditions

Backgrounds

To explain the excess cardiovascular mortality observed in the SERVE-HF study, it was hypothesized that the high-pressure ASV default settings used lead to inappropriate ventilation, cascading negative consequences (i.e. not only pro-arrythmogenic effects through metabolic/electrolyte abnormalities, but also lower cardiac output). The aims of this study are: i) to describe ASV-settings for long-term ASV-populations in real-life conditions; ii) to describe the associated minute-ventilations (MV) and therapeutic pressures for servo-controlled-flow versus servo-controlled-volume devices (ASV-F Philips®-devices versus ASV-V ResMed®-devices).

Methods

The OTRLASV-study is a cross-sectional, 5-centre study including patients who underwent ASV-treatment for at least 1 year. The eight participating clinicians were free to adjust ASV settings, which were compared among i) initial diagnosed sleep-disordered-breathing (SBD) groups (Obstructive-Sleep-Apnea (OSA), Central-Sleep-Apnea (CSA), Treatment-Emergent-Central-Sleep-Apnea (TECSA)), and ii) unsupervised groups (k-means clusters). To generate these clusters, baseline and follow-up variables were used (age, sex, body mass index (BMI), initial diagnosed Obstructive-Apnea-Index, initial diagnosed Central-Apnea-Index, Continuous-Positive-Airway-Pressure used before ASV treatment, presence of cardiopathy, and presence of a reduced left-ventricular-ejection-fraction (LVEF)). ASV-data were collected using the manufacturer’s software for 6 months.

Results

One hundred seventy-seven patients (87.57% male) were analysed with a median (IQ_25–75) initial Apnea-Hypopnea-Index of 50 (38–62)/h, an ASV-treatment duration of 2.88 (1.76–4.96) years, 61.58% treated with an ASV-V. SDB groups did not differ in ASV settings, MV or therapeutic pressures. In contrast, the five generated k-means clusters did (generally described as follows: (C1) male-TECSA-cardiopathy, (C2) male-mostly-CSA-cardiopathy, (C3) male-mostly-TECSA-no cardiopathy, (C4) female-mostly-elevated BMI-TECSA-cardiopathy, (C5) male-mostly-OSA-low-LVEF). Of note, the male-mostly-OSA-low-LVEF-cluster-5 had significantly lower fixed end-expiratory-airway-pressure (EPAP) settings versus C1 (p = 0.029) and C4 (p = 0.007). Auto-EPAP usage was higher in the male-mostly-TECSA-no cardiopathy-cluster-3 versus C1 (p = 0.006) and C2 (p < 0.001). MV differences between ASV-F (p = 0.002) and ASV-V (p < 0.001) were not homogenously distributed across clusters, suggesting specific cluster and ASV-algorithm interactions. Individual ASV-data suggest that the hyperventilation risk is not related to the cluster nor the ASV-monitoring type.

Conclusions

Real-life ASV settings are associated with combinations of baseline and follow-up variables wherein cardiological variables remain clinically meaningful. At the patient level, a hyperventilation risk exists regardless of cluster or ASV-monitoring type, spotlighting a future role of MV-telemonitoring in the interest of patient-safety.

Trial registration

The OTRLASV study was registered on ClinicalTrials.gov (Identifier: NCT02429986). 1 April 2015.

Adaptive servo-ventilation in patients with chronic heart failure and sleep disordered breathing: predictors of usage

PURPOSE

Adaptive servo-ventilation (ASV) is a therapy designed for patients with central sleep apnea (CSA) and Cheyne Stokes respiration. The aim of this study was to find predictors of ASV usage in patients with CSA in a routine sleep clinic cohort.

METHODS

In this retrospective study, consecutive patients in whom ASV therapy was initiated at the University Hospital Regensburg between 2011 and 2015, were analyzed. Analysis included polysomnographies of diagnostic and ASV initiation nights, a phone questionnaire on ASV usage, readout of the ASV device 1 month after initiation ("early ASV usage," 1 month after ASV initiation), and the readout of the last month before a reappointment date set in 2015 ("late ASV usage," median 17 months after ASV initiation).

RESULTS

In 69 consecutive patients, the mean early and late ASV usage per night was 4.8 ± 2.5 h and 4.1 ± 3.0 h, respectively. Seventeen months after initiation, 57% of patients used the device ≥ 4 h per night, and of those 91% reported a subjective benefit from ASV therapy. Early ASV usage was significantly associated with late ASV usage (univariable regression: Beta 0.8, 95%CI [0.6; 1.0] p < 0.001). In multivariable regression analysis, short duration of slow wave sleep (N3) during diagnostic polysomnography (Beta - 6.2, 95%CI [- 11.0; - 1.5]; p = 0.011) and subjective benefit from ASV (Beta 174.0, 95%CI [68.6; 279.5]; p = 0.002) were significantly associated with longer late ASV usage.

CONCLUSION

Early ASV usage predicts late ASV usage. In addition, low slow wave sleep before ASV initiation and subjective benefit from ASV may contribute to higher late ASV usage.

Cohort profile: FACE, prospective follow-up of chronic heart failure patients with sleep-disordered breathing indicated for adaptive servo ventilation

PURPOSE

FACE is a prospective cohort study designed to assess the effect of adding adaptive servoventilation (ASV) to standard care on morbidity and mortality in patients with chronic heart failure (HF) with preserved (HFpEF), mid-range (HFmrEF) or reduced ejection fraction (HFrEF) who have sleep-disordered breathing (SDB) with an indication for ASV. We describe the study design, ongoing data collection and baseline participant characteristics.

PARTICIPANTS

Consecutive patients with HFpEF, HFmrEF or HFrEF plus SDB with central sleep apnoea (CSA) and indication for ASV were enrolled in the study cohort between November 2009 and December 2018; the ASV group includes those treated with ASV and the control group consists of patients who refused ASV or stopped treatment early. Follow-up is based on standard clinical practice, with visits at inclusion, after 3, 12 and 24 months of follow-up. Primary endpoint is the time to first event: all-cause death or unplanned hospitalisation (or unplanned prolongation of a planned hospitalisation) for worsening of HF, cardiovascular death or unplanned hospitalisation for worsening of HF, and all-cause death or all-cause unplanned hospitalisation.

FINDINGS TO DATE

503 patients have been enrolled, mean age of 72 years, 88% male, 31% with HFrEF. HF was commonly of ischaemic origin, and the number of comorbidities was high. SDB was severe (median Apnoea-Hypopnoea Index 42/hour), and CSA was the main indication for ASV (69%). HF was highly symptomatic; most patients were in NYHA class II (38%) or III (29%).

FUTURE PLANS

Patient follow-up is ongoing. Given the heterogeneous nature of the enrolled population, a decision was made to use latent class analysis to define homogeneous patient subgroups, and then evaluate outcomes by cluster, and in the ASV and control groups (overall and within patient clusters). First analysis will be performed after 3 months, a second analysis at the 2-year follow-up.

TRIAL REGISTRATION NUMBER

NCT01831128; Pre-results.

Meta-Analysis Comparing Outcomes of Therapies for Patients With Central Sleep Apnea and Heart Failure With Reduced Ejection Fraction

Patients with heart failure with reduced ejection fraction and predominant central sleep apnea pose treatment challenges. A system review and meta-analysis of randomized controlled trials (RCTs) were undertaken. Electronic searches of digital repositories, journals, specialty society and manufacturer websites, manual searches of reference sections of RCTs, and published clinical guidelines were performed. Studies were graded for bias. Meta-analytic random effects models were used. Outcomes of interest included: sleep, cardiovascular, mortality, and quality of life (QoL). Grading of recommendations assessment, development and evaluation was performed. Nineteen randomized studies were identified that met the inclusion criteria of apnea hypopnea index (AHI) ≥10, predominant central sleep apnea (CSA), and heart failure with reduced ejection fraction (HFrEF) ≤50%. Most trials examined adaptive servo ventilation (ASV) (8 studies) and continuous positive airway pressure (CPAP) (9 studies). Bias existed in that: 15 of 19 (79%) of the trials lacked blinding, 10 of 19 were manufacturer funded, and with attrition in 8 of 19 studies. In meta-analysis, ASV performed better than control on sleep but not on QoL or cardiovascular outcomes, including mortality. CPAP demonstrated positive short-term outcomes on sleep, cardiovascular, and QoL (3 months). Longer-term cardiovascular and mortality data did not show benefit. Drug therapies demonstrated a positive clinical effect short term on sleep outcomes only. Transvenous phrenic nerve stimulation (TPNS) demonstrated positive treatment outcomes on sleep and QoL at 6 months. Evidence suggests improvement in cardiovascular outcomes with TPNS. In conclusion, ASV and CPAP therapies improve sleep, but long-term QoL or cardiovascular benefit was lacking. TPNS exhibited positive outcomes on sleep and QoL at 6 months with positive trends in CV outcomes.

The use and effectiveness of adaptive servo ventilation in central sleep apnea: a study of consecutive sleep clinic patients

The use of adaptive servo ventilation to treat central sleep apnea in the clinical setting is incompletely understood and could be under-utilized. We reviewed our experience of adaptive servo ventilation use in patients with central sleep apnea. This study shows the effectiveness of adaptive servo ventilation in treating patients with central sleep apnea, irrespective of a predisposing factor, as assessed during a 4-week treatment trial. Results show that adaptive servo ventilation was effective and superior to continuous positive airway pressure in controlling central sleep apnea and improving symptoms. Only a small proportion of these patients had comorbid heart failure. Early treatment with adaptive servo ventilation may improve long-term adherence to therapy. These findings highlight the utility of adaptive servo ventilation in the management of central sleep apnea.

[Cardiac dysfunction and the obstructive sleep apnoea syndrome]

INTRODUCTION

Cardiac insufficiency affects nearly 2% of the population with increased morbidity/mortality despite advances in therapeutic management. The sleep apnoea syndrome (SAS) is a risk factor for, and cause of aggravation of, myocardial dysfunction.

BACKGROUND

SAS is found in 70% of patients with chronic cardiac failure, 65% of patients with refractory hypertension, 60% of patients with cerebro-vascular accidents and 50% of patients with atrial fibrillation. The associated cardiovascular mortality is multiplied by a factor of 2 to 3. The pathophysiological mechanisms are intermittent nocturnal hypoxia, variations in CO₂ levels, variations in intrathoracic pressure and repeated arrousals from sleep, concurrent with sympathetic hyperactivity, endothelial dysfunction and systemic inflammation.

CONCLUSIONS

SAS and cardiological management in patients presenting with myocardial dysfunction should be combined. It is necessary to pursue the scientific investigations with the aim of determining a precise care pathway and the respective places of each of the cardiological and pulmonary measures.

[Central sleep apnea in patients with chronic heart failure]

Cheyne-Stokes respiration (CSR) is a form of sleep-disordered breathing seen in approximately half of patients with chronic heart failure and low left ventricular ejection fraction. The authors describe clinical features of CSR, mortality rate, treatment variants. Effects of continuous positive airway pressure (CPAP), bi-level ventilation, adaptive servoventilation (ASV) in patients with CSR and chronic heart failure are discussed. Diuretic acetazolamide is one more therapeutic option for CSR. It improves central sleep apnea and related daytime symptoms in patients with heart failure.

More than Heart Failure: Central Sleep Apnea and Sleep-Related Hypoventilation

Central sleep apnea (CSA) comprises a variety of breathing patterns and clinical entities. They can be classified into 2 categories based on the partial pressure of carbon dioxide in the arterial blood. Nonhypercapnic CSA is usually characterized by a periodic breathing pattern, while hypercapnic CSA is based on hypoventilation. The latter CSA form is associated with central nervous, neuromuscular, and rib cage disorders as well as obesity and certain medication or substance intake. In contrast, nonhypercapnic CSA is typically accompanied by an overshoot of the ventilation and often associated with heart failure, cerebrovascular diseases, and stay in high altitude. CSA and hypoventilation syndromes are often considered separately, but pathophysiological aspects frequently overlap. An integrative approach helps to recognize underlying pathophysiological mechanisms and to choose adequate therapeutic strategies. Research in the last decades improved our insights; nevertheless, diagnostic tools are not always appropriately chosen to perform comprehensive sleep studies. This supports misinterpretation and misclassification of sleep disordered breathing. The purpose of this article is to highlight unresolved problems, raise awareness for different pathophysiological components and to discuss the evidence for targeted therapeutic strategies.

Use of adaptive servo ventilation therapy as treatment of sleep-disordered breathing and heart failure: a systematic review and meta-analysis

PURPOSE

Adaptive servoventilation (ASV) has been reported to show improvement in patients with sleep-disordered breathing (SDB) and heart failure (HF); however, its role as a second-line or adjunctive treatment is not clear. We conducted a systematic review and meta-analysis of new existing data including cardiac mechanistic factor, geometry, and cardiac biomarkers.

METHODS

We systematically searched for randomized controlled trials (RCTs) and cohort studies that assessed the efficacy or effectiveness of ASV compared to conventional treatments for SDB and HF in five research databases from their inception to November 2018. Random-effects meta-analyses using the inverse variance method and stratified by study design were performed.

RESULTS

We included 15 RCTs (n = 859) and 5 cohorts (n = 162) that met our inclusion criteria. ASV significantly improved left ventricular ejection fraction (LVEF) in cohorts (MD 6.96%, 95% CI 2.58, 11.34, p = 0.002), but not in RCTs. Also, the ASV group had significantly lower apnea-hypopnea index (AHI) in both cohorts (MD - 26.02, 95% CI - 36.94, - 15.10, p < 0.00001) and RCTs (MD - 21.83, 95% CI - 28.17, - 15.49, p < 0.00001). ASV did not significantly decrease the E/e' ratio in RCTs or in cohorts. Finally, ASV significantly decreased brain natriuretic peptide (BNP) in the cohorts (SMD - 121.99, CI 95% - 186.47, - 57.51, p = 0.0002) but not in RCTs. ASV did not have a significant effect on systolic blood pressure, diastolic blood pressure, and cardiac diameters.

CONCLUSIONS

ASV therapy is associated with improvements of AHI in comparison to alternative treatments in patients with SDB and HF. ASV did not improve LVEF or E/e' ratios in randomized trials; other intermediate outcomes did not improve significantly.

Treatment of central sleep apnea in patients with heart failure: Now and future

Heart failure (HF) is known to be associated with sleep-disordered breathing (SDB). In addition to disturbing patients’ sleep, SDB is also associated with a deterioration in the cardiac function and an increased mortality and morbidity. Central sleep apnea (CSA), typically characterized by Cheyne-Stokes breathing (CSB), is increasingly found in patients with HF compared to the general population. An important pathogenetic factor of CSA seen in HF patients is an instability in the control of the respiratory system, characterized by both hypocapnia and increased chemosensitivity. Sympathetic overactivation, pulmonary congestion and increased chemosensitivity associated with HF stimulate the pulmonary vagal irritant receptor, resulting in chronic hyperventilation and hypocapnia. Additionally, the repetitive apnea and arousal cycles induce cyclic sympathetic activation, which may worsen the cardiac prognosis. Correcting CSB may improve both patient’s quality of life and HF syndrome itself. However, a treatment for HF in patients also experiencing CSA is yet to be found. In fact, conflicting results from numerous clinical studies investigating sleep apnea with HF guide to a troubling question, that is whether (or not) sleep apnea should be treated in patients with HF? This editorial attempts to both collect the current evidence about randomized control trials investigating CSA in patients with HF and highlight the effect of specific CSA treatments on cardiovascular endpoints.

[Transvenous neurostimulation in central sleep apnea associated with heart failure]

Sleep-related breathing disorders can be classified as either obstructive (OSA) or central sleep apnea (CSA). Whereas there is substantial knowledge about the pathophysiology and sound recommendations for the diagnosis and treatment of OSA, the origin of CSA is still incompletely understood, patient identification is difficult and the necessity for specific treatment is under debate. CSA often accompanies heart failure and is associated with an adverse prognosis. Optimized heart failure treatment reduces CSA and is thus the cornerstone of CSA treatment. In contrast to OSA, noninvasive ventilation does not lead to prognostic improvement in CSA and ASV ventilation may even lead to an increase in mortality. Transvenous neurostimuation of the phrenic nerve is currently under clinical investigation as a new therapeutic modality for CSA. Early results demonstrate positive effects on sleep parameters and quality of life without any evidence for a negative impact on mortality. However, these results await confirmation in larger studies before this new approach can be advocated for routine clinical use.

Sleep Apnea, the Risk of Developing Heart Failure, and Potential Benefits of Continuous Positive Airway Pressure (CPAP) Therapy

Background

Whether there is an association between sleep apnea (SA) and the risk of developing heart failure (HF) is unclear. Furthermore, it has never been established whether continuous positive airway pressure (CPAP) therapy can prevent development of HF. We aimed to investigate SA patients’ risk of developing HF and the association of CPAP therapy.

Methods and Results

Using nationwide databases, the entire Danish population was followed from 2000 until 2012. patients with SA receiving and not receiving CPAP therapy were identified and compared with the background population. The primary end point was first‐time hospital contact for HF and adjusted incidence rate ratios of HF were calculated using Poisson regression models. Among 4.9 million individuals included, 40 485 developed SA during the study period (median age: 53.4 years, 78.5% men) of whom 45.2% received CPAP therapy. Crude rates of HF were increased in all patients with SA relative to the background population. In the adjusted model, the incidence rate ratios of HF were increased in the untreated SA patients of all ages, compared with the background population. Comparing the CPAP‐treated patients with SA with the untreated patients with SA showed significantly lower incidence rate ratios of HF among older patients.

Conclusions

In this nationwide cohort study, SA not treated with CPAP was associated with an increased risk of HF in patients of all ages. Use of CPAP therapy was associated with a lower risk of incident HF in patients >60 years of age, suggesting a protective effect of CPAP therapy in the elderly.

Home Mechanical Ventilation: An Overview

Prevalence studies have shown heterogeneous use of home mechanical ventilation in different conditions, with a marked increase in uptake especially in users of noninvasive ventilation. Although randomized controlled trials have examined noninvasive ventilation in acute exacerbations of chronic obstructive pulmonary disease, for weaning from invasive ventilation and for postextubation respiratory failure, the evidence base for long-term noninvasive ventilation and comparisons with invasive ventilation are less well developed. The combination of noninvasive ventilation and cough-assist devices has reduced the indications for tracheotomy ventilation in some situations (e.g., Duchenne muscular dystrophy, spinal muscular atrophy, myopathies, and amyotrophic lateral sclerosis) and has also prolonged survival. Several excellent overviews have been written on the history of home mechanical ventilation and its evolution from negative pressure to positive pressure techniques, including a systematic review of outcomes. This review, instead, will cover recent trials, trends in the field, outcomes, and safety. Because the greatest growth has been in home noninvasive ventilation, this will be the main focus of this article.

Sleep apnea: a review of diagnostic sensors, algorithms, and therapies

While public awareness of sleep related disorders is growing, sleep apnea syndrome (SAS) remains a public health and economic challenge. Over the last two decades, extensive controlled epidemiologic research has clarified the incidence, risk factors including the obesity epidemic, and global prevalence of obstructive sleep apnea (OSA), as well as establishing a growing body of literature linking OSA with cardiovascular morbidity, mortality, metabolic dysregulation, and neurocognitive impairment. The US Institute of Medicine Committee on Sleep Medicine estimates that 50-70 million US adults have sleep or wakefulness disorders. Furthermore, the American Academy of Sleep Medicine (AASM) estimates that more than 29 million US adults suffer from moderate to severe OSA, with an estimated 80% of those individuals living unaware and undiagnosed, contributing to more than $149.6 billion in healthcare and other costs in 2015. Although various devices have been used to measure physiological signals, detect apneic events, and help treat sleep apnea, significant opportunities remain to improve the quality, efficiency, and affordability of sleep apnea care. As our understanding of respiratory and neurophysiological signals and sleep apnea physiological mechanisms continues to grow, and our ability to detect and process biomedical signals improves, novel diagnostic and treatment modalities emerge.

OBJECTIVE

This article reviews the current engineering approaches for the detection and treatment of sleep apnea.

APPROACH

It discusses signal acquisition and processing, highlights the current nonsurgical and nonpharmacological treatments, and discusses potential new therapeutic approaches.

MAIN RESULTS

This work has led to an array of validated signal and sensor modalities for acquiring, storing and viewing sleep data; a broad class of computational and signal processing approaches to detect and classify SAS disease patterns; and a set of distinctive therapeutic technologies whose use cases span the continuum of disease severity.

SIGNIFICANCE

This review provides a current perspective of the classes of tools at hand, along with a sense of their relative strengths and areas for further improvement.

Cardiovascular Outcomes With Minute Ventilation-Targeted Adaptive Servo-Ventilation Therapy in Heart Failure: The CAT-HF Trial

BACKGROUND

Sleep apnea is common in hospitalized heart failure (HF) patients and is associated with increased morbidity and mortality.

OBJECTIVES

The CAT-HF (Cardiovascular Improvements With MV-ASV Therapy in Heart Failure) trial investigated whether minute ventilation (MV) adaptive servo-ventilation (ASV) improved cardiovascular outcomes in hospitalized HF patients with moderate-to-severe sleep apnea.

METHODS

Eligible patients hospitalized with HF and moderate-to-severe sleep apnea were randomized to ASV plus optimized medical therapy (OMT) or OMT alone (control). The primary endpoint was a composite global rank score (hierarchy of death, cardiovascular hospitalizations, and percent changes in 6-min walk distance) at 6 months.

RESULTS

126 of 215 planned patients were randomized; enrollment was stopped early following release of the SERVE-HF (Adaptive Servo-Ventilation for Central Sleep Apnea in Systolic Heart Failure) trial results. Average device usage was 2.7 h/night. Mean number of events measured by the apnea-hypopnea index decreased from 35.7/h to 2.1/h at 6 months in the ASV group versus 35.1/h to 19.0/h in the control group (p < 0.0001). The primary endpoint did not differ significantly between the ASV and control groups (p = 0.92 Wilcoxon). Changes in composite endpoint components were not significantly different between ASV and control. There was no significant interaction between treatment and ejection fraction (p = 0.10 Cox model); however, pre-specified subgroup analysis suggested a positive effect of ASV in patients with HF with preserved ejection fraction (p = 0.036).

CONCLUSIONS

In hospitalized HF patients with moderate-to-severe sleep apnea, adding ASV to OMT did not improve 6-month cardiovascular outcomes. Study power was limited for detection of safety signals and identifying differential effects of ASV in patients with HF with preserved ejection fraction, but additional studies are warranted in this population. (Cardiovascular Improvements With MV ASV Therapy in Heart Failure [CAT-HF]; NCT01953874).

A Practical Approach to the Identification and Management of Sleep-Disordered Breathing in Heart Failure Patients

Sleep-disordered breathing (SDB) is a major health problem affecting much of the general population. Although SDB is responsible for rapid progression of heart failure (HF) and the worsening morbidity and mortality, advanced HF state is associated with accelerated development of SDB. In the face of recent developments in SDB treatment and availability of effective therapeutic options known to improve quality of life, exercise tolerance, and heart function, most HF patients with SDB are left unrecognized and untreated. This article provides an overview of SDB in HF with focus on practical approaches intended to facilitate screening and treatment.

Patients with Cheyne-Stokes respiration and heart failure: patient tolerance after three-month discontinuation of treatment with adaptive servo-ventilation

The recent SERVE HF study concluded that patients with chronic heart failure (CHF) and Cheyne-Stokes respiration (CSR) have increased mortality when treated with adaptive servo-ventilation (ASV). We, therefore, wanted to explore if these patients tolerated discontinuation of ASV treatment. The study was a prospective post-ASV treatment observational design with a 3-month follow-up period. 14 patients from our outpatient clinic, all male, were originally diagnosed with CHF and Cheyne-Stokes respiration, which is a clinical form of central sleep apnea. Left ventricular ejection fraction (LVEF) was ≤45% when ASV treatment was initiated. Median machine use was 68 (42-78) months when the patients were instructed to terminate ASV treatment. The patients were then followed during conventional CHF treatment for 3 months. Study baseline was set the last ASV treatment day. Sleep data were collected from the machine the last day of use. Apnea-hypopnea index (AHI), LVEF, 6-min walk test and 24-h ambulatory electrocardiogram recordings were performed at baseline and at study end. Life quality data were obtained using The Minnesota Living with Heart Failure Questionaire (MLHFQ). New York Heart Association Functional Classification (NYHA) was registered. An ambulatory sleep screening was performed at study end. AHI increased significantly after 3 months without ASV treatment [from 1.6 (0.8-3.2) to 39.2 (24.3-44.1, p = 0.001)]. Quality of life (QOL) decreased significantly: 30 (13-54) at discontinuation of ASV vs. 46 (24-67) (MLHFQ) at study end, p = 0.04. Though there was no significant change in NYHA functional class, patients especially reported increased shortness of breath, reduced concentration and reduced memory after discontinuation of ASV treatment. There were no significant differences in LVEF, heart rhythm data and physical capacity. Left ventricular function was preserved indicating that discontinuation of ASV in heart failure patients does not affect cardiac capacity. There was a significant decrement in QOL that must be considered in further treatment of these patients.

Quality of life improves in patients with chronic heart failure and Cheyne-Stokes respiration treated with adaptive servo-ventilation in a nurse-led heart failure clinic

AIMS AND OBJECTIVES

The aim of this study was to investigate if quality of life improved in chronic heart failure patients with Cheyne-Stokes respiration treated with adaptive servo-ventilation in nurse-led heart failure clinic.

BACKGROUND

Cheyne-Stokes respiration is associated with decreased quality of life in patients with chronic heart failure. Adaptive servo-ventilation is introduced to treat this sleep-disordered breathing.

DESIGN

Randomised, controlled design.

METHODS

Fifty-one patients (ranging from 53-84 years), New York Heart Association III-IV and/or left ventricular ejection fraction ≤40% and Cheyne-Stokes respiration were randomised to an intervention group who received adaptive servo-ventilation or a control group. Minnesota Living with Heart Failure Questionnaire was used to assess quality of life at randomisation and after three months. Both groups were followed in the nurse-led heart failure clinic.

RESULT

Adaptive servo ventilation improved quality of life-scores both in a per protocol analysis and in an intention to treat analysis. Twenty-one patients dropped out of the study, nine in the control and 12 in the intervention group.

CONCLUSION

Use of adaptive servo-ventilation improved quality of life in chronic heart failure patients with Cheyne-Stokes respiration. However, the drop-out rate was high.

RELEVANCE TO CLINICAL PRACTICE

Chronic heart failure patients come regularly to the nurse-led heart failure clinic. The heart failure nurses' competency has to include knowledge of equipment to provide support and continuity of care to the patients.

Sleep-Disordered Breathing During Congestive Heart Failure: To Intervene or Not to Intervene?

Sleep-disordered breathing is common in heart failure patients and is associated with increased morbidity and mortality. Central sleep apnea occurs more commonly in heart failure-reduced ejection fraction, and obstructive sleep apnea occurs more frequently in heart failure with preserved ejection fraction. Although the two types of sleep-disordered breathing have distinct pathophysiologic mechanisms, both contribute to abnormal cardiovascular consequences. Treatment with continuous positive airway pressure for obstructive sleep apnea in heart failure has been well defined, whereas treatment strategies for central sleep apnea in heart failure continue to evolve. Unilateral transvenous neurostimulation has shown promise for the treatment of central sleep apnea. In this paper, we examine the current state of knowledge of treatment options for sleep-disordered breathing in heart failure.

Definition, discrimination, diagnosis and treatment of central breathing disturbances during sleep

The complexity of central breathing disturbances during sleep has become increasingly obvious. They present as central sleep apnoeas (CSAs) and hypopnoeas, periodic breathing with apnoeas, or irregular breathing in patients with cardiovascular, other internal or neurological disorders, and can emerge under positive airway pressure treatment or opioid use, or at high altitude. As yet, there is insufficient knowledge on the clinical features, pathophysiological background and consecutive algorithms for stepped-care treatment. Most recently, it has been discussed intensively if CSA in heart failure is a “marker” of disease severity or a “mediator” of disease progression, and if and which type of positive airway pressure therapy is indicated. In addition, disturbances of respiratory drive or the translation of central impulses may result in hypoventilation, associated with cerebral or neuromuscular diseases, or severe diseases of lung or thorax. These statements report the results of an European Respiratory Society Task Force addressing actual diagnostic and therapeutic standards. The statements are based on a systematic review of the literature and a systematic two-step decision process. Although the Task Force does not make recommendations, it describes its current practice of treatment of CSA in heart failure and hypoventilation.

Noninvasive Positive Pressure Ventilation in Chronic Heart Failure

Instruction and Objectives. Noninvasive positive pressure ventilation (NPPV) alleviates sleep-disordered breathing (SDB) and it may improve cardiac function in SDB patients. Because large randomized controlled trials directly evaluating the impact of NPPV on cardiac function are lacking, we conducted a meta-analysis of published data on effectiveness of NPPV in improving cardiac function in patients with chronic heart failure regardless of SDB presence. Methods. Controlled trials were identified in PubMed, OVID, and EMBASE databases. Both fixed and randomized models were used in meta-analysis with primary outcomes of left ventricular ejection fraction (LVEF). Results. Nineteen studies were included with a total of 843 patients. Compared to standard medical treatment (SMT) plus sham-NPPV or SMT only, NPPV plus SMT was associated with improvement in LVEF (weighted mean difference 5.34, 95% CI, [3.85,6.82]; P < 0.00001) and plasma brain natriuretic peptide (BNP) level (weighted mean difference -117.37, 95% CI, [-227.22, -7.52]; P = 0.04) and no influence on overall mortality (RR 1.00, 95% CI, [0.96,1.04]; P = 0.95). Conclusions. In the present meta-analysis, use of NPPV plus SMT improved LVEF and reduced plasma BNP level but did not improve overall mortality in patients with chronic heart failure.

Transvenous neurostimulation for central sleep apnoea: a randomised controlled trial

BACKGROUND

Central sleep apnoea is a serious breathing disorder associated with poor outcomes. The remedé system (Respicardia Inc, Minnetonka, MN, USA) is an implantable device which transvenously stimulates a nerve causing diaphragmatic contraction similar to normal breathing. We evaluated the safety and effectiveness of unilateral neurostimulation in patients with central sleep apnoea.

METHODS

We recruited patients from 31 hospital-based centres in Germany, Poland, and the USA in this prospective, multicentre, randomised trial. Participants had to have been medically stable for at least 30 days and have received appropriate guideline recommended therapy, be aged at least 18 years, be expected to tolerate study procedures, and willing and able to comply with study requirements. Eligible patients with an apnoea-hypopnoea index (AHI) of at least 20 events per h, tested by a polysomnography, underwent device implantation and were randomly assigned (1:1) by a computer-generated method stratified by site to either stimulation (treatment) or no stimulation (control) for 6 months. The primary effectiveness endpoint in the intention-to-treat population was the comparison of the proportions of patients in the treatment versus control groups achieving a 50% or greater AHI reduction from baseline to 6 months, measured by a full-night polysomnography assessed by masked investigators in a core laboratory. The primary safety endpoint of 12-month freedom from serious adverse events related to the procedure, system, or therapy was evaluated in all patients. This trial is active, but not recruiting, and is registered with ClinicalTrials.gov (NCT01816776).

FINDINGS

Between April 17, 2013, and May 28, 2015, we randomly assigned 151 eligible patients to the treatment (n=73) or control (n=78) groups. In the analysis of the intention-to-treat population, significantly more patients in the treatment group (35 [51%] of 68) had an AHI reduction from baseline of 50% or greater at 6 months than had those in the control group (eight [11%] of 73; difference between groups 41%, 95% CI 25-54, p<0·0001). 138 (91%) of 151 patients had no serious-related adverse events at 12 months. Seven (9%) cases of related-serious adverse events occurred in the control group and six (8%) cases were reported in the treatment group. Seven patients died (unrelated to implant, system, or therapy), four deaths (two in treatment group and two in control group) during the 6-month randomisation period when neurostimulation was delivered to only the treatment group and was off in the control group, and three deaths between 6 months and 12 months of follow-up when all patients received neurostimulation. 27 (37%) of 73 patients in the treatment group reported non-serious therapy-related discomfort that was resolved with simple system reprogramming in 26 (36%) patients, but was unresolved in one (1%) patient.

INTERPRETATION

Transvenous neurostimulation significantly reduced the severity of central sleep apnoea, including improvements in sleep metrics, and was well tolerated. The clinically meaningful effects of the therapy are supported by the concordant improvements in oxygenation and quality of life, making transvenous neurostimulation a promising therapeutic approach for central sleep apnoea.

FUNDING

Respicardia Inc.

Congestive Heart Failure and Central Sleep Apnea

Congestive heart failure (CHF) is among the most common causes of admission to hospitals in the United States, especially in those over age 65. Few data exist regarding the prevalence CHF of Cheyne-Stokes respiration (CSR) owing to congestive heart failure in the intensive care unit (ICU). Nevertheless, CSR is expected to be highly prevalent among those with CHF. Treatment should focus on the underlying mechanisms by which CHF increases loop gain and promotes unstable breathing. Few data are available to determine prevalence of CSR in the ICU, or how CSR might affect clinical management and weaning from mechanical ventilation.

Updated Adaptive Servo-Ventilation Recommendations for the 2012 AASM Guideline: "The Treatment of Central Sleep Apnea Syndromes in Adults: Practice Parameters with an Evidence-Based Literature Review and Meta-Analyses"

ABSTRACT

An update of the 2012 systematic review and meta-analyses were performed and a modified-GRADE approach was used to update the recommendation for the use of adaptive servo-ventilation (ASV) for the treatment of central sleep apnea syndrome (CSAS) related to congestive heart failure (CHF). Meta-analyses demonstrated an improvement in LVEF and a normalization of AHI in all patients. Analyses also demonstrated an increased risk of cardiac mortality in patients with an LVEF of ≤ 45% and moderate or severe CSA predominant sleep-disordered breathing. These data support a Standard level recommendation against the use of ASV to treat CHF-associated CSAS in patients with an LVEF of ≤ 45% and moderate or severe CSAS, and an Option level recommendation for the use of ASV in the treatment CHF-associated CSAS in patients with an LVEF > 45% or mild CHF-related CSAS. The application of these recommendations is limited to the target patient populations; the ultimate judgment regarding propriety of any specific care must be made by the clinician.

New modes in non-invasive ventilation

Non-invasive ventilation is useful to treat some forms of respiratory failure. Hence, the number of patients receiving this treatment is steadily increasing. Considerable conceptual and technical progress has been made in the last years by manufacturers concerning this technique. This includes new features committed to improve its effectiveness as well as patient-ventilator interactions. The goal of this review is to deal with latest advances in ventilatory modes and features available for non-invasive ventilation. We present a comprehensive analysis of new modes of ventilator assistance committed to treat respiratory failure (hybrid modes) and central and complex sleep apnea (adaptive servo ventilation), and of new modes of triggering and cycling (neurally adjusted ventilatory assist). Technical aspects, modes of operation and settings of these new features as well as an exhaustive review of published data, their benefits and limits, and the potential place of these devices in clinical practice, are discussed.

Adaptive servo-ventilation therapy for patients with chronic heart failure in a confirmatory, multicenter, randomized, controlled study

BACKGROUND

Adaptive servo-ventilation (ASV) therapy is expected to be novel nonpharmacotherapy with hemodynamic effects on patients with chronic heart failure (CHF), but sufficient evidence has not been obtained.

METHODS AND RESULTS

A 24-week, open-label, randomized, controlled study was performed to confirm the cardiac function-improving effect of ASV therapy on CHF patients. At 39 institutions, 213 outpatients with CHF, whose left ventricular ejection fraction (LVEF) was <40% and who had mild to severe symptoms [New York Heart Association (NYHA) class: ≥II], were enrolled. After excluding 8 patients, 102 and 103 underwent ASV plus guideline-directed medical therapy (GDMT) [ASV group] and GDMT only [control group], respectively. The primary endpoint was LVEF, and the secondary endpoints were HF deterioration, B-type natriuretic peptide (BNP), and clinical composite response (CCR: NYHA class+HF deterioration). LVEF and BNP improved significantly at completion against the baseline values in the 2 groups. However, no significant difference was found between these groups. HF deterioration tended to be suppressed. The ASV group showed a significant improvement in CCR corroborated by significant improvements in NYHA class and ADL against the control group.

CONCLUSIONS

Under the present study's conditions, ASV therapy was not superior to GDMT in the cardiac function-improving effect but showed a clinical status-improving effect, thus indicating a given level of clinical benefit.

Altered breathing syndrome in heart failure: newer insights and treatment options

In patients with heart failure (HF), altered breathing patterns, including periodic breathing, Cheyne-Stokes breathing, and oscillatory ventilation, are seen in several situations. Since all forms of altered breathing cause similar detrimental effects on clinical outcomes, they may be considered collectively as an "altered breathing syndrome." Altered breathing syndrome should be recognized as a comorbid condition of HF and as a potential therapeutic target. In this review, we discuss mechanisms and therapeutic options of altered breathing while sleeping, while awake at rest, and during exercise.