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.

The efficacy and safety of adaptive servo-ventilation therapy for heart failure with preserved ejection fraction

It is unclear whether adaptive servo-ventilation (ASV) therapy for heart failure with preserved ejection fraction (HFpEF) is effective. The aim of this study was to investigate the details of ASV use, and to evaluate the effectiveness and safety of ASV in real-world HFpEF patients. We retrospectively enrolled 36 HFpEF patients at nine cardiovascular centers who initiated ASV therapy during hospitalization or on outpatient basis and were able to continue using it at home from 2012 to 2017 and survived for at least one year thereafter. The number of hospitalizations for heart failure (HF) during the 12 months before and 12 months after introduction of ASV at home was compared. The median number of HF hospitalizations for each patient was significantly reduced from 1 [interquartile range: 1-2] in the 12 months before introduction of ASV to 0 [0-0] in the 12 months after introduction of ASV (p < 0.001). In subgroup analysis, reduction in heart failure hospitalization was significantly greater in female patients, patients with a body mass index < 25, and those with moderate or severe tricuspid valve regurgitation. In patients with HFpEF, the number of HF hospitalizations was significantly decreased after the introduction of ASV. HFpEF patients with female sex, BMI < 25, or moderate to severe tricuspid valve regurgitation are potential candidates who might benefit from ASV therapy.

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.

Adaptive Servo-ventilation Therapy Results in the Prevention of Arrhythmias in Patients with Heart Failure Due to Ischemic Heart Disease

Objective Whether or not adaptive servo-ventilation (ASV) is effective in preventing arrhythmias in patients with heart failure (HF) due to ischemic heart disease (IHD) is unclear. This study estimated the effects of ASV therapy on arrhythmias in patients with HF due to IHD. Methods One hundred and forty-one consecutive hospitalized patients with HF due to IHD (mean age: 74.9±11.9 years old) were retrospectively assessed in this study. Of the 141 patients, 75 were treated with ASV (ASV group), and 66 were treated without ASV (Non-ASV group). We estimated the incidence of arrhythmias, including paroxysmal atrial fibrillation (PAF) and ventricular tachycardia (VT), during one-year follow-up in both groups using multivariable logistic regression models. Results Men accounted for 55.3% of the study population. There were no significant differences in the baseline clinical characteristic data between the ASV and Non-ASV groups with respect to age, sex, heart rate, risk factors, oral medication, or laboratory data, including the estimated glomerular filtration rate (eGFR), brain natriuretic peptide, and left ventricular ejection fraction. ASV therapy was associated with a reduced incidence of arrhythmia after adjusting for demographic and cardiovascular disease risk factors (odds ratio, 0.27; 95% confidence interval, 0.11 to 0.63; p<0.01; compared to the Non-ASV group). In addition, at the 1-year follow-up, an improvement (increase) in the eGFR was found in the ASV group but not in the Non-ASV group. Conclusion ASV therapy was able to prevent arrhythmias, including PAF and VT, with short-term improvements in the renal function in patients with HF due to IHD.

Effects of central apneas on sympathovagal balance and hemodynamics at night: impact of underlying systolic heart failure

BACKGROUND

Increased sympathetic drive is the key determinant of systolic heart failure progression, being associated with worse functional status, arrhythmias, and increased mortality. Central sleep apnea is highly prevalent in systolic heart failure, and its effects on sympathovagal balance (SVB) and hemodynamics might depend on relative phase duration and background pathophysiology.

OBJECTIVE

This study compared the effects of central apneas in patients with and without systolic heart failure on SVB and hemodynamics during sleep.

METHODS

During polysomnography, measures of SVB (heart rate and diastolic blood pressure variability) were non-invasively recorded and analyzed along with baroreceptor reflex sensitivity and hemodynamic parameters (stroke volume index, cardiac index, total peripheral resistance index). Data analysis focused on stable non-rapid eye movement N2 sleep, comparing normal breathing with central sleep apnea in subjects with and without systolic heart failure.

RESULTS

Ten patients were enrolled per group. In heart failure patients, central apneas had neutral effects on SVB (all p > 0.05 for the high, low, and very low frequency components of heart rate and diastolic blood pressure variability). Patients without heart failure showed an increase in very low and low frequency components of diastolic blood pressure variability in response to central apneas (63 ± 18 vs. 39 ± 9%; p = 0.001, 43 ± 12 vs. 31 ± 15%; p = 0.002). In all patients, central apneas had neutral hemodynamic effects when analyzed over a period of 10 min, but had significant acute hemodynamic effects.

CONCLUSION

Effects of central apneas on SVB during sleep depend on underlying systolic heart failure, with neutral effects in heart failure and increased sympathetic drive in idiopathic central apneas.

Adaptive servo-ventilation therapy does not favourably alter sympatho-vagal balance in sleeping patients with systolic heart failure and central apnoeas: Preliminary data

BACKGROUND

In contrast to continuous positive airway pressure (CPAP), the use of adaptive servo-ventilation (ASV) for treatment of central sleep apnoea (CSA) was associated with increased mortality in patients with chronic systolic heart failure (CHF). In order to characterize the interplay between sleep-disordered breathing, CHF and sympathovagal balance (SVB) this study investigated the effect of nocturnal CPAP and ASV on SVB in CSA patients with or without CHF.

METHODS

Thirty-seven patients with ongoing positive airway pressure therapy (CPAP or ASV) for CSA (17 patients with systolic CHF - left ventricular ejection fraction <50% - and 20 patients with CSA but no CHF) underwent evaluation of SVB (spectral analysis of heart rate -HRV- and diastolic blood pressure variability) during full nocturnal polysomnography. The night was randomly split into equal parts including no treatment (NT), automatic CPAP and ASV. Data analysis was restricted to stable N2 sleep.

RESULTS

In patients with CSA and systolic CHF, neither automatic CPAP nor ASV showed favourable effects on parameters reflecting SVB during N2 sleep (all p > 0.05). In contrast, in subjects with CSA without CHF automatic CPAP, but not ASV, favourably altered SVB by decreasing the low frequency and increasing the high frequency component of HRV (both p = 0.03).

CONCLUSIONS

Effects of various modes of positive airway pressure therapy of CSA on SVB during sleep depend on the mode of pressure support and underlying cardiac function. Automatic CPAP but not ASV favourably influences SVB in subjects without CHF, whereas both interventions leave SVB unchanged in patients with CHF.

Early therapeutic effects of adaptive servo-ventilation on cardiac sympathetic nervous function in patients with heart failure evaluated using a combination of 11C-HED PET and 123I-MIBG SPECT

RATIONALE

Adaptive servo-ventilation (ASV), a novel respiratory support therapy for sleep disorders, may improve cardiac function in heart failure (HF). However, the reasons that ASV improves cardiac function have not been fully studied especially in sympathetic nervous function (SNF). The purpose of the present study was to investigate the effects of ASV therapy on cardiac SNF in patients with HF.

METHODS

We evaluated ASV therapeutic effects before and 6 months after ASV therapy in 9 HF patients [57.3 ± 17.3 years old, left ventricular ejection fraction (LVEF) 36.1 ± 16.7%]. We performed echocardiography, polysomnography, biomarkers, 11C-hydroxyephedrine (HED) PET as a presynaptic function marker and planar 123I-metaiodobenzylguanidine (MIBG) to evaluate washout rate.

RESULTS

ASV therapy reduced apnea-hypopnea index (AHI) and improved plasma brain natriuretic peptide (BNP) concentration. In 123I-MIBG imaging, the early heart/mediastinum (H/M) ratio increased after ASV therapy (2.19 ± 0.58 to 2.40 ± 0.67; P = 0.045). Washout rate did not change (23.8 ± 7.3% to 23.8 ± 8.8%; P = 0.122). Global 11C-HED retention index (RI) improved from 0.068 ± 0.033/s to 0.075 ± 0.034/s (P = 0.029).

CONCLUSIONS

ASV reduced AHI and improved BNP. ASV might initially improve presynaptic cardiac sympathetic nervous function in HF patients after 6 months of treatment.

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.

An application of pacemaker respiratory monitoring system for the prediction of heart failure

Sleep-disordered breathing (SDB) is one of the most common complications among heart failure (HF) patients. Changes of respiratory patterns during the various stages in patients with HF have not been fully investigated. In this case, the algorism using thoracic impedance sensor and minute ventilation (sleep apnea monitoring [SAM] algorithm) with implanted pacemaker (REPLY 200 SR or DR, Sorin CRM SAS, Clamart, France) was used to monitor respiration. Impedance data from the implanted pacemaker can be converted into respiratory data, which can be used to calculate the respiratory disturbance index (RDI) per unit of time. Using this algorithm, we observed a sudden appearance of abnormal breathing at the onset of HF, followed by gradual improvement of respiratory patterns during the recovery stage. The results from respiratory monitoring using the SAM algorithm were strongly correlated with those from the positive airway pressure device. This case report could imply that proper utilization of this sensor could facilitate the early detection and therapeutic control of HF.

What is the Optimal Strategy for Adaptive Servo-Ventilation Therapy?

Clinical advantages in the adaptive servo-ventilation (ASV) therapy have been reported in selected heart failure patients with/without sleep-disorder breathing, whereas multicenter randomized control trials could not demonstrate such advantages. Considering this discrepancy, optimal patient selection and device setting may be a key for the successful ASV therapy. Hemodynamic and echocardiographic parameters indicating pulmonary congestion such as elevated pulmonary capillary wedge pressure were reported as predictors of good response to ASV therapy. Recently, parameters indicating right ventricular dysfunction also have been reported as good predictors. Optimal device setting with appropriate pressure setting during appropriate time may also be a key. Large-scale prospective trial with optimal patient selection and optimal device setting is warranted.

Epidemiology of Sleep-Disordered Breathing and Heart Failure: What Drives What

PURPOSE OF REVIEW

The bidirectional relationships that have been demonstrated between heart failure (HF) and central sleep apnea (CSA) demand further exploration with respect to the implications that each condition has for the other. This review discusses the body of literature that has accumulated on these relationships and how CSA and its potential treatment may affect outcomes in patients with CSA.

RECENT FINDINGS

Obstructive sleep apnea (OSA) can exacerbate hypertension, type 2 diabetes, obesity, and atherosclerosis, which are known predicates of HF. Conversely, patients with HF more frequently exhibit OSA partly due to respiratory control system instability. These same mechanisms are responsible for the frequent association of HF with CSA with or without a Hunter-Cheyne-Stokes breathing (HCSB) pattern. Just as is the case with OSA, patients with HF complicated by CSA exhibit more severe cardiac dysfunction leading to increased mortality; the increase in severity of HF can in turn worsen the degree of sleep disordered breathing (SDB). Thus, a bidirectional relationship exists between HF and both phenotypes of SDB; moreover, an individual patient may exhibit a combination of these phenotypes. Both types of SDB remain significantly underdiagnosed in patients with HF and hence undertreated. Appropriate screening for, and treatment of, OSA is clearly a significant factor in the comprehensive management of HF, while the relevance of CSA remains controversial. Given the unexpected results of the Treatment of Sleep-Disordered Breathing with Predominant Central Sleep Apnea by Adaptive Servo Ventilation in Patients with Heart Failure trial, it is now of paramount importance that additional analysis of these data be expeditiously reported. It is also critical that ongoing and proposed prospective studies of this issue proceed without delay.

Beneficial effects of adaptive servo-ventilation therapy on readmission and medical costs in patients with chronic heart failure

Adaptive servo-ventilation (ASV) therapy is a novel modality of noninvasive positive pressure ventilation and is now widely utilized to treat patients with chronic heart failure (CHF). However, there has been no clinical study of the effect of ASV therapy on readmission and cost-effectiveness for the treatment of CHF. The present study was conducted to evaluate the clinical efficacy and cost-effectiveness of home ASV therapy in 45 patients with a history of two or more admissions a year for worsening CHF. Seven patients refused to undergo chronic ASV therapy and three died. Thus, 35 patients were eventually enrolled in the present study. New York Heart Association class (2.8 ± 0.4 versus 2.3 ± 0.5, p < 0.001), log plasma B-type natriuretic peptide level (2.53 ± 0.44 versus 2.29 ± 0.40 pg/mL, p < 0.0001), left atrial dimension (47.5 ± 7.0 versus 44.9 ± 7.6 mm, p = 0.014), and mitral regurgitation area ratio (20.3 ± 12.1 versus 16.9 ± 8.9%, p = 0.007) decreased significantly after 12 months of ASV therapy. The frequency of hospitalization after ASV was significantly lower than before ASV (1.0 ± 1.0 versus 2.3 ± 0.5 times/year/patient, p < 0.0001). ASV also decreased the duration of hospitalization from 64.4 ± 46.5 to 22.8 ± 27.5 days/year/patient (p < 0.0001). Consequently, the total medical costs were reduced by 37% after ASV (1.95 ± 1.37 versus 3.11 ± 1.75 million yen/patient, p = 0.003). ASV therapy reduced readmissions and medical costs in patients with CHF.

Biomarkers in Sleep Apnea and Heart Failure

PURPOSE OF REVIEW

Sleep-disordered breathing (SDB) is highly prevalent in heart failure (HF) and may confer significant stress to the cardiovascular system and increases the risk for future cardiovascular events. The present review will provide updates on the current understanding of the relationship of SDB and common HF biomarkers and the effect of positive airway pressure therapy on these biomarkers, with particular emphasis in patients with coexisting SDB and HF.

RECENT FINDINGS

Prior studies have examined the relationship between HF biomarkers and SDB, and the effect of SDB treatment on these biomarkers, with less data available in the context of coexisting SDB and HF. Overall, however, the association of SDB and circulating biomarkers has been inconsistent. Further research is needed to elucidate the relationship between biomarkers and SDB in HF, to evaluate the clinical utility of biomarkers over standard methods in large, prospective studies and also to assess the impact of treatment of SDB on these biomarkers in HF via interventional studies.

Optimization of pressure settings during adaptive servo-ventilation support using real-time heart rate variability assessment: initial case report

Background

Adaptive servo-ventilation (ASV) therapy is a recent non-invasive positive pressure ventilation therapy that was developed for patients with heart failure (HF) refractory to optimal medical therapy. However, it is likely that ASV therapy at relatively higher pressure setting worsens some of the patients’ prognosis compared with optimal medical therapy. Therefore, identification of optimal pressure settings of ASV therapy is warranted.

Case presentation

We present the case of a 42-year-old male with HF, which was caused by dilated cardiomyopathy, who was admitted to our institution for evaluating his eligibility for heart transplantation. To identify the optimal pressure setting [peak end-expiratory pressure (PEEP) ramp test], we performed an ASV support test, during which the PEEP settings were set at levels ranging from 4 to 8 mmHg, and a heart rate variability (HRV) analysis using the MemCalc power spectral density method. Clinical parameters varied dramatically during the PEEP ramp test. Over incremental PEEP levels, pulmonary capillary wedge pressure, cardiac index and high-frequency level (reflecting parasympathetic activity) decreased; however, the low-frequency level increased along with increase in plasma noradrenaline concentrations.

Conclusions

An inappropriately high PEEP setting may stimulate sympathetic nerve activity accompanied by decreased cardiac output. This was the first report on the PEEP ramp test during ASV therapy. Further research is warranted to determine whether use of optimal pressure settings using HRV analyses may improve the long-term prognosis of such patients.

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.

Adaptive servo-ventilation suppresses elevation of C-reactive protein and sympathetic activity in acute uncomplicated type B aortic dissection

OBJECTIVES

The aim of this prospective, randomized study was to investigate the effects of adaptive servo-ventilation (ASV), based on haemodynamic parameters, sympathetic status and respiratory conditions in patients with acute uncomplicated type B aortic dissection.

METHODS

We enrolled 28 patients with acute uncomplicated type B aortic dissection requiring antihypertensive therapies, who had been admitted within 24 h from onset. Study subjects were randomly assigned either to the ASV group (n = 14) or to the non-ASV group (n = 14).

RESULTS

Antihypertensive therapy at an acute phase led to significant reduction in blood pressure in both groups. Heart rate significantly dropped in the ASV group. In the non-ASV group, noradrenaline (746 ± 343 to 912 ± 402 pg/ml, P = 0.033) and dopamine (30 ± 21 to 42 ± 28 pg/ml, P = 0.015) significantly increased at 1 h after admission. Low frequency/high frequency ratios significantly decreased in the ASV group (2.1 ± 1.6 to 1.7 ± 1.1, P = 0.045). During follow-up at the subacute period, pleural effusion significantly increased in the non-ASV group (649 ± 611 vs 190 ± 292%, P = 0.033). Peak C-reactive protein (CRP) had a significant positive correlation with pleural effusion volume (P = 0.039) and was significantly greater in the non-ASV group (15.5 ± 6.3 vs 8.5 ± 6.1 mg/dl, P= 0.009).

CONCLUSIONS

In acute type B aortic dissection, ASV was considered to have suppressed the development of sympathetic nervous activity, pleural effusion and elevation of peak CRP.

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.

Sleep-disordered breathing in heart failure

Sleep-disordered breathing-comprising obstructive sleep apnoea (OSA), central sleep apnoea (CSA), or a combination of the two-is found in over half of heart failure (HF) patients and may have harmful effects on cardiac function, with swings in intrathoracic pressure (and therefore preload and afterload), blood pressure, sympathetic activity, and repetitive hypoxaemia. It is associated with reduced health-related quality of life, higher healthcare utilization, and a poor prognosis. Whilst continuous positive airway pressure (CPAP) is the treatment of choice for patients with daytime sleepiness due to OSA, the optimal management of CSA remains uncertain. There is much circumstantial evidence that the treatment of OSA in HF patients with CPAP can improve symptoms, cardiac function, biomarkers of cardiovascular disease, and quality of life, but the quality of evidence for an improvement in mortality is weak. For systolic HF patients with CSA, the CANPAP trial did not demonstrate an overall survival or hospitalization advantage for CPAP. A minute ventilation-targeted positive airway therapy, adaptive servoventilation (ASV), can control CSA and improves several surrogate markers of cardiovascular outcome, but in the recently published SERVE-HF randomized trial, ASV was associated with significantly increased mortality and no improvement in HF hospitalization or quality of life. Further research is needed to clarify the therapeutic rationale for the treatment of CSA in HF. Cardiologists should have a high index of suspicion for sleep-disordered breathing in those with HF, and work closely with sleep physicians to optimize patient management.

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.

Sleep-disordered Breathing in Heart Failure

Sleep-disordered breathing affects over half of patients with heart failure (HF) and is associated with a poor prognosis. It is an under-diagnosed condition and may be a missed therapeutic target. Obstructive sleep apnoea is caused by collapse of the pharynx, exacerbated by rostral fluid shift during sleep. The consequent negative intrathoracic pressure, hypoxaemia, sympathetic nervous system activation and arousals have deleterious cardiovascular effects. Treatment with continuous positive airway pressure may confer symptomatic and prognostic benefit in this group. In central sleep apnoea, the abnormality is with regulation of breathing in the brainstem, often causing a waxing-waning Cheyne Stokes respiration pattern. Non-invasive ventilation has not been shown to improve prognosis in these patients and the recently published SERVE-HF trial found increased mortality in those treated with adaptive servoventilation. The management of sleep-disordered breathing in patients with HF is evolving rapidly with significant implications for clinicians involved in their care.

Adaptive Servo-Ventilation Has More Favorable Acute Effects on Hemodynamics Than Continuous Positive Airway Pressure in Patients With Heart Failure

Adaptive servo-ventilation (ASV) has been attracting attention as a novel respiratory support therapy for heart failure (HF). However, the acute hemodynamic effects have not been compared between ASV and continuous positive airway pressure (CPAP) in HF patients.We studied 12 consecutive patients with stable chronic HF. Hemodynamic measurement was performed by right heart catheterization before and after CPAP 5 cmH2O, CPAP 10 cmH2O, and ASV for 15 minutes each.Heart rate, blood pressure, pulmonary capillary wedge pressure (PCWP), and stroke volume index (SVI) were not changed by any intervention. Right atrial pressure significantly increased after CPAP 10 cmH2O (3.6 ± 3.3 to 6.7 ± 1.6 mmHg, P = 0.005) and ASV (4.1 ± 2.6 to 6.8 ± 1.5 mmHg, P = 0.026). Cardiac index was significantly decreased by CPAP 10 cmH2O (2.3 ± 0.4 to 1.9 ± 0.3 L/minute/m(2), P = 0.048), but was not changed by ASV (2.3 ± 0.4 to 2.0 ± 0.3 L/ minute/m(2), P = 0.299). There was a significant positive correlation between baseline PCWP and % of baseline SVI by CPAP 10 cmH2O (r = 0.705, P < 0.001) and ASV (r = 0.750, P < 0.001). ASV and CPAP 10 cmH2O had significantly greater slopes of this correlation than CPAP 5 cmH2O, suggesting that patients with higher PCWP had a greater increase in SVI by ASV and CPAP 10 cmH2O. The relationship between baseline PCWP and % of baseline SVI by ASV was shifted upwards compared to CPAP 10 cmH2O. Furthermore, based on the results of a questionnaire, patients accepted CPAP 5 cmH2O and ASV more favorably compared to CPAP 10 cmH2O.ASV had more beneficial effects on acute hemodynamics and acceptance than CPAP in HF patients.

Adaptive servo-ventilation therapy of central sleep apnoea and its effect on sleep quality

OBJECTIVES

Poor sleep quality is common in patients with chronic heart failure (CHF). This study tested the hypothesis that adaptive servo-ventilation (ASV) therapy in CHF patients whose central sleep apnoea (CSA) was not suppressed by continuous positive airway pressure (CPAP) (CPAP-non-responders) would improve sleep quality compared to CPAP-responders receiving ongoing CPAP therapy.

METHODS

Eighty-two patients with CHF (65 ± 9 years, left ventricular ejection fraction 35 ± 16 %) and CSA [apnoea-hypopnoea index (AHI) ≥15/h] were retrospectively studied. Within an average of 47 days, patients were reevaluated on CPAP therapy and stratified according to their suppression of CSA: 34 were CPAP-non-responders switched to ASV therapy the following day and 48 were CPAP-responders who continued on CPAP therapy. Polysomnographic parameters were assessed in the diagnostic night and on the last night of PAP therapy (CPAP or ASV) before the patient was discharged with the final pressure settings.

RESULTS

Compared with the CPAP group, the ASV group had significantly greater reductions from baseline in AHI (-37 ± 15/h vs -28 ± 18/h, p = 0.02), arousal index (-12.7 ± 13.6/h vs -6.8 ± 12.5/h, p = 0.04) and sleep stage N1 (-9 ± 14 % vs -2 ± 12 %, p = 0.03). In addition, the ASV group gained significantly more rapid eye movement (REM) sleep compared with the CPAP group (+5 ± 9 % vs +1 ± 9 %, p = 0.02).

CONCLUSIONS

CPAP therapy is effective in reducing AHI in a significant proportion of CHF patients with reduced ejection fraction and CSA. Treatment of CSA with ASV in CHF patients reduces sleep fragmentation and improves sleep structure to a significantly greater extent than changes seen in responders to CPAP therapy.

Central sleep apnoea-a clinical review

Central sleep apnoea (CSA) is characterised by recurrent apnoeas during sleep with no associated respiratory effort. It mostly results from withdrawal of the wakefulness drive in sleep leaving ventilation under metabolic control. A detailed physiological understanding of the control of breathing in wakefulness and sleep is essential to the understanding of CSA. It encompasses a diverse group of conditions with differing aetiologies and pathophysiology. Likewise treatment varies according to underlying aetiology. Some of the conditions such as idiopathic (primary) CSA (ICSA) are relatively rare and benign. On the other hand Cheyne-Stokes breathing (CSB) pattern is quite common in patients with heart failure and might be a prognostic indicator of poor outcome. Unfortunately modern medical management of heart failure does not seem to have significantly reduced the prevalence of CSA in this group. Since the adoption of positive airway pressure (PAP) as a common treatment modality of obstructive sleep apnoea (OSA), complex CSA has been increasingly observed either as treatment emergent or persistent CSA. Depending on the particular condition, various treatment strategies have been tried in the past two decades which have included hypnotic therapy, respiratory stimulants, judicious administration of carbon dioxide, oxygen therapy, PAP and bi-level ventilatory support with a backup rate. In the past decade adaptive servo ventilation (ASV) has been introduced with much promise. Various studies have shown its superiority over other treatment modalities. Ongoing long term studies will hopefully shed more light on its impact on cardiovascular morbidity and mortality. Other rare forms are still poorly understood and treatments remain suboptimal.

The effect of adaptive servo-ventilation on dyspnoea, haemodynamic parameters and plasma catecholamine concentrations in acute cardiogenic pulmonary oedema

BACKGROUND

Adaptive servo-ventilation has a potential sympathoinhibitory effect in acute cardiogenic pulmonary oedema (ACPO).

AIMS

To evaluate the acute effects of adaptive servo-ventilation in patients with ACPO.

METHODS

Fifty-eight consecutive patients with ACPO were divided into those who underwent adaptive servo-ventilation and those who received oxygen therapy alone as part of their immediate care. Visual analogue scale, vital signs, blood gas data and plasma catecholamine concentrations at baseline and 1 h during emergency care, and subsequent clinical events (death within 30 days, intubation within seven days or between seven and 30 days, and length of hospital stay) were assessed. Pre-matched and post-propensity score (PS)-matched datasets were analysed.

RESULTS

During the first hour of adaptive servo-ventilation, plasma catecholamine concentrations fell significantly (baseline versus 1 h: epinephrine p = 0.003, norepinephrine p < 0.001, dopamine p < 0.001), with falls in blood pressure, heart rate, respiratory rate and pCO2, and rise in HCO3 and pH. In the PS-matched model, visual analogue scale (p = 0.036), systolic blood pressure (from 153.8 ± 30.7 to 133.1 ± 16.3 mmHg; p = 0.025) and plasma dopamine concentration (p = 0.034) fell significantly in the adaptive servo-ventilation group compared with the oxygen therapy alone group. The clinical outcomes between the groups were comparable.

CONCLUSION

In patients with ACPO, emergency care using adaptive servo-ventilation attenuated plasma catecholamine concentrations and led to the improvement of dyspnoea, vital signs and acid-base balance, without adversely influencing clinical outcomes. Using adaptive servo-ventilation, rather than standard oxygen alone, may relieve dyspnoea and improve haemodynamic status, possibly by modulating sympathetic nerve activity.

Adaptive servo-ventilation therapy using an innovative ventilator for patients with chronic heart failure: a real-world, multicenter, retrospective, observational study (SAVIOR-R)

Adaptive servo-ventilation (ASV) therapy using an innovative ventilator—originally developed to treat sleep-disordered breathing (SDB)—is a novel modality of noninvasive positive pressure ventilation and is gaining acceptance among Japanese cardiologists in expectation of its applicability to treat patients with chronic heart failure (CHF) based on its acute beneficial hemodynamic effects. We conducted a multicenter, retrospective, real-world observational study in 115 Japanese patients with CHF, who had undergone home ASV therapy for the first time from January through December 2009, to examine their profile and the effects on their symptoms and hemodynamics. Medical records were used to investigate New York Heart Association (NYHA) class, echocardiographic parameters including left ventricular ejection fraction (LVEF), cardiothoracic ratio (CTR), brain natriuretic peptide (BNP), and other variables. Most of the patients were categorized to NYHA classes II (44.4 %) and III (40.7 %). SDB severity was not determined in 44 patients, and SDB was not detected or was mild in 27 patients. In at least 71 patients (61.7 %), therefore, ASV therapy was not applied for the treatment of SDB. CHF was more severe, i.e., greater NYHA class, lower LVEF, and higher CTR, in 87 ASV-continued patients (75.7 %) than in 28 ASV-discontinued patients (24.3 %). However, SDB severity was not related to continuity of ASV. The combined proportion of NYHA classes III and IV (P = 0.012) and LVEF (P = 0.009) improved significantly after ASV therapy. CTR and BNP did not improve significantly after ASV therapy but showed significant beneficial changes in their time-course analysis (P < 0.05, respectively). Improvements in LVEF and NYHA class after ASV therapy were not influenced by SDB severity at onset. The present study suggests that ASV therapy would improve the symptoms and hemodynamics of CHF patients, regardless of SDB severity. A randomized clinical study to verify these effects is warranted.

Effects of short-term continuous positive airway pressure on myocardial sympathetic nerve function and energetics in patients with heart failure and obstructive sleep apnea: a randomized study

BACKGROUND

Heart failure with reduced ejection fraction and obstructive sleep apnea (OSA), 2 states of increased metabolic demand and sympathetic nervous system activation, often coexist. Continuous positive airway pressure (CPAP), which alleviates OSA, can improve ventricular function. It is unknown whether this is due to altered oxidative metabolism or presynaptic sympathetic nerve function. We hypothesized that short-term (6-8 weeks) CPAP in patients with OSA and heart failure with reduced ejection fraction would improve myocardial sympathetic nerve function and energetics.

METHODS AND RESULTS

Forty-five patients with OSA and heart failure with reduced ejection fraction (left ventricular ejection fraction 35.8±9.7% [mean±SD]) were evaluated with the use of echocardiography and 11C-acetate and 11C-hydroxyephedrine positron emission tomography before and ≈6 to 8 weeks after randomization to receive short-term CPAP (n=22) or no CPAP (n=23). Work metabolic index, an estimate of myocardial efficiency, was calculated as follows: (stroke volume index×heart rate×systolic blood pressure÷Kmono), where Kmono is the monoexponential function fit to the myocardial 11C-acetate time-activity data, reflecting oxidative metabolism. Presynaptic sympathetic nerve function was measured with the use of the 11C-hydroxyephedrine retention index. CPAP significantly increased hydroxyephedrine retention versus no CPAP (Δretention: +0.012 [0.002, 0.021] versus -0.006 [-0.013, 0.005] min(-1); P=0.003). There was no significant change in work metabolic index between groups. However, in those with more severe OSA (apnea-hypopnea index>20 events per hour), CPAP significantly increased both work metabolic index and systolic blood pressure (P<0.05).

CONCLUSIONS

In patients with heart failure with reduced ejection fraction and OSA, short-term CPAP increased hydroxyephedrine retention, indicating improved myocardial sympathetic nerve function, but overall did not affect energetics. In those with more severe OSA, CPAP may improve cardiac efficiency. Further outcome-based investigation of the consequences of CPAP is warranted.

CLINICAL TRIAL REGISTRATION URL

http://www.clinicaltrials.gov. Unique identifier: NCT00756366.

Effective treatment of congestive heart failure using adaptive servo-ventilation in an end-stage renal disease patient on hemodialysis

A 61-year-old man who was being treated with hemodialysis (HD) for end-stage renal disease presented with symptoms of severe congestive heart failure (CHF). Removing excess intravascular fluid during HD was difficult due to the patient's chronic hypotension induced by severe left ventricular (LV) dysfunction. The application of adaptive servo-ventilation (ASV) increased the patient's cardiac output and blood pressure during HD, thus resulting in the effective removal of excess intravascular fluid. Therefore, ASV may be effective for treating CHF in HD patients with LV dysfunction and chronic hypotension.

Complex sleep apnea

OPINION STATEMENT

Complex sleep apnea currently refers to the emergence and persistence of central apneas and hypopneas following the application of positive airway pressure therapy in patients with obstructive sleep apnea. However, this narrow definition is an "outcome" and does not capture the spectrum of pathological activation of the respiratory chemoreflex in sleep apnea. The International Classification of Sleep Disorders - 3rd edition recognizes the phenomenon of Treatment-Related Central Sleep Apnea, but the phenotype is usually evident prior to onset of therapy. The key polysomnographic characteristics of chemoreflex modulated and mediated sleep apnea are nonrapid eye movement (NREM) dominance of respiratory events, short (<30 seconds) or long (>60 seconds) cycle time with a self-similar metronomic timing, and spontaneous improvement during rapid eye movement (REM) sleep. Thus, the majority of chemoreflex effects go unrecognized due to the bias toward obstructive sleep apnea's current scoring criteria. Any treatment of apparently obstructive sleep apnea, including surgery and oral appliances, can expose chemoreflex-driven instabilities. As both sleep fragmentation and a narrow CO2 reserve or increased loop gain drive the disease, sedatives (to induce longer periods of stable NREM sleep and reduce the destabilizing effects of arousals in NREM sleep) and CO2-based stabilization approaches are logical. Adaptive ventilation reduces mean hyperventilation yet can induce ventilator-patient desynchrony, while enhanced expiratory rebreathing space (EERS, dead space during positive pressure therapy) and CO2 manipulation directly stabilize respiratory control by moving CO2 above the apnea threshold. Carbonic anhydrase inhibition can provide further adjunctive benefits. Novel pharmacological approaches may target mediators of carotid body hypoxic sensitization, such as the balance between gas neurotransmitters. In complex apnea patients, single mode therapy is unlikely to be successful, and the power of multi-modality therapy should be harnessed for optimal outcomes.