The SERVE-HF Trial

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

BACKGROUND

In patients with heart failure and reduced ejection fraction, sleep-disordered breathing, comprising obstructive sleep apnoea (OSA) and central sleep apnoea (CSA), is associated with increased morbidity, mortality, and sleep disruption. We hypothesised that treating sleep-disordered breathing with a peak-flow triggered adaptive servo-ventilation (ASV) device would improve cardiovascular outcomes in patients with heart failure and reduced ejection fraction.

METHODS

We conducted a multicentre, multinational, parallel-group, open-label, phase 3 randomised controlled trial of peak-flow triggered ASV in patients aged 18 years or older with heart failure and reduced ejection fraction (left ventricular ejection fraction ≤45%) who were stabilised on optimal medical therapy with co-existing sleep-disordered breathing (apnoea-hypopnoea index [AHI] ≥15 events/h of sleep), with concealed allocation and blinded outcome assessments. The trial was carried out at 49 hospitals in nine countries. Sleep-disordered breathing was stratified into predominantly OSA with an Epworth Sleepiness Scale score of 10 or lower or predominantly CSA. Participants were randomly assigned to standard optimal treatment alone or standard optimal treatment with the addition of ASV (1:1), stratified by study site and sleep apnoea type (ie, CSA or OSA), with permuted blocks of sizes 4 and 6 in random order. Clinical evaluations were performed and Minnesota Living with Heart Failure Questionnaire, Epworth Sleepiness Scale, and New York Heart Association class were assessed at months 1, 3, and 6 following randomisation and every 6 months thereafter to a maximum of 5 years. The primary endpoint was the cumulative incidence of the composite of all-cause mortality, first admission to hospital for a cardiovascular reason, new onset atrial fibrillation or flutter, and delivery of an appropriate cardioverter-defibrillator shock. All-cause mortality was a secondary endpoint. Analysis for the primary outcome was done in the intention-to-treat population. This trial is registered with ClinicalTrials.gov (NCT01128816) and the International Standard Randomised Controlled Trial Number Register (ISRCTN67500535), and the trial is complete.

FINDINGS

The first and last enrolments were Sept 22, 2010, and March 20, 2021. Enrolments terminated prematurely due to COVID-19-related restrictions. 1127 patients were screened, of whom 731 (65%) patients were randomly assigned to receive standard care (n=375; mean AHI 42·8 events per h of sleep [SD 20·9]) or standard care plus ASV (n=356; 43·3 events per h of sleep [20·5]). Follow-up of all patients ended at the latest on June 15, 2021, when the trial was terminated prematurely due to a recall of the ASV device due to potential disintegration of the motor sound-abatement material. Over the course of the trial, 41 (6%) of participants withdrew consent and 34 (5%) were lost to follow-up. In the ASV group, the mean AHI decreased to 2·8-3·7 events per h over the course of the trial, with associated improvements in sleep quality assessed 1 month following randomisation. Over a mean follow-up period of 3·6 years (SD 1·6), ASV had no effect on the primary composite outcome (180 events in the control group vs 166 in the ASV group; hazard ratio [HR] 0·95, 95% CI 0·77-1·18; p=0·67) or the secondary endpoint of all-cause mortality (88 deaths in the control group vs. 76 in the ASV group; 0·89, 0·66-1·21; p=0·47). For patients with OSA, the HR for all-cause mortality was 1·00 (0·68-1·46; p=0·98) and for CSA was 0·74 (0·44-1·23; p=0·25). No safety issue related to ASV use was identified.

INTERPRETATION

In patients with heart failure and reduced ejection fraction and sleep-disordered breathing, ASV had no effect on the primary composite outcome or mortality but eliminated sleep-disordered breathing safely.

FUNDING

Canadian Institutes of Health Research and Philips RS North America.

Analysis of the effect of CPAP on hemodynamics using clinical data and a theoretical model: CPAP therapy decreases cardiac output mechanically but increases it via afterload reduction

BACKGROUND

Noninvasive positive pressure ventilation (NIPPV) has been established as an effective treatment for heart failure. Positive airway pressure such as continuous positive airway pressure (CPAP) increases cardiac output (CO) in some patients but decreases it in others. However, the mechanism behind such unpredictable responses remains undetermined.

METHODS AND RESULTS

We measured hemodynamic parameters of 38 cases using Swan-Ganz catheter before and after CPAP in chronic heart failure status. In those whose CO increased by CPAP, pulmonary vascular resistance (PVR) was significantly decreased and SpO2 significantly increased, but the other parameters were not changed. On the other hand, PVR was not changed, but systemic vascular resistance (SVR) was increased in those whose CO decreased by CPAP. To explain this phenomenon, we simulated the cardiovascular system using a cardiac model of time-varying elastance. In this model, it was indicated that CPAP decreases CO irrespective of cardiac function or filling status under constant PVR condition. However, when reduction of PVR by CPAP was taken into account, an increase in CO was expected especially in the hypervolemic and low right ventricle (RV) systolic function cases.

CONCLUSIONS

CPAP would increase CO only where PVR can be reduced by CPAP therapy, especially in the case with hypervolemia and/or low RV systolic function. Understanding the underlying mechanism should help identify the patients for whom NIPPV would be effective.

A State-of-the-Art Review on Sleep Apnea Syndrome and Heart Failure

Heart failure (HF) affects many patients worldwide every year. It represents a leading cause of hospitalization and still, today, mortality remains high, albeit the progress in treatment strategies. Several factors contribute to the development and progression of HF. Among these, sleep apnea syndrome represents a common but still underestimated factor because its prevalence is substantially higher in patients with HF than in the general population and is related to a worse prognosis. This review summarizes the current knowledge about sleep apnea syndrome coexisting with HF in terms of morbidity and mortality to provide actual and future perspectives about the diagnosis, evaluation, and treatment of this association.

Positive airway pressure therapy for post-stroke sleep disordered breathing: a systematic review, meta-analysis and meta-regression

BACKGROUND

Sleep disordered breathing (SDB) is an under-recognised independent risk factor and a potential consequence of stroke. We systematically reviewed and meta-analysed the effectiveness of positive airway pressure (PAP) therapy in improving post-stroke outcomes.

METHODS

We searched CENTRAL, Embase, PubMed, CINAHL, PsycINFO, Scopus, ProQuest, Web of Science and CNKI (China National Knowledge Infrastructure) for randomised controlled trials comparing PAP therapy against a control or placebo group. We evaluated the pooled effects of PAP therapy on recurrent vascular events, neurological deficit, cognition, functional independence, daytime sleepiness and depression using random effects meta-analyses.

RESULTS

We identified 24 studies. Our meta-analyses showed that PAP therapy reduced recurrent vascular events (risk ratio 0.47, 95% CI 0.28-0.78), and showed significant beneficial effects on neurological deficit (Hedges' g= -0.79, 95% CI -1.19- -0.39), cognition (g=0.85, 95% CI 0.04-1.65), functional independence (g=0.45, 95% CI 0.01-0.88) and daytime sleepiness (g= -0.96, 95% CI -1.56- -0.37). However, there was insignificant reduction in depression (g= -0.56, 95% CI -2.15-1.02). No publication bias was detected.

CONCLUSIONS

Post-stroke patients with SDB benefited from PAP therapy. Prospective trials are needed to determine the ideal initiation period and the minimum effective therapeutic dose.

Diagnostic and therapeutic approach of central sleep apnea in heart failure - the role of adaptive servo-ventilation. A statement of the Portuguese society of pulmonology and the Portuguese sleep association

It is known that patients with heart failure (HF) have an increased risk of developing central sleep apnoea (CSA), with Cheyne-Stokes respiration. The development of servo-ventilation aimed to treat CSA and improve the quality of life (QoL) of these patients. A large randomized clinical study, SERVE-HF, was conducted in order to test this theory in patients with HF and reduced ejection fraction (HFrEF). The results from this trial seemed to indicate that, in these patients, there was no beneficial effect of the assisted ventilation in CSA treatment. More surprisingly, an increased rate of all-cause or cardiovascular mortality was observed. This has led to dramatic changes in clinical practice, with decreased frequency of servo-ventilation prescription across Europe, including Portugal, due to changes in the guidelines. However, SERVE-HF was conducted only in severe systolic HF patients with CSA, and caution must be taken when extrapolating these results to HF patients with preserved ejection fraction or CSA patients without HF. The study also showed poor adherence, methodological and statistical gaps, including study design, patient selection, data collection and analysis, treatment adherence, and group crossovers, which have not been discussed in the trial as potential confounding factors and raise several concerns. Moreover, the adaptive servo-ventilation (ASV) device used in SERVE-HF was unable to lower the minimum support pressure below 3 mm H₂0, and this has been suggested as one of the probable contributing reasons to the excess mortality observed in this study. This limitation has since been solved, and this ASV device is no longer used. This paper describes the results of a Portuguese Task Force on the treatment of central sleep apnoea in patients with chronic HF.

Cheyne-stokes respiration in children with heart failure

Cheyne-Stokes respiration (CSA-CSR) is a form of central sleep apnea characterized by alternating periods of hyperventilation and central apneas or hypopneas. CSA-CSR develops following a cardiac insult resulting in a compensatory increase in sympathetic activity, which in susceptible patients causes hyperventilation and destabilizes respiratory control. The physiological changes that occur in CSA-CSR include hyperventilation, a reduced blood gas buffering capacity, and circulatory delay. In adults, 25% to 50% of patients with heart failure are reported to have CSA-CSR. The development of CSA-CSR in this group of patients is considered a poor prognostic sign. The prevalence, progression, and treatment outcomes of CSA-CSR in children remain unclear with only 11 children being described in the literature. The lack of data is possibly not due to the paucity of children with severe heart failure and CSA-CSR but because they may be under-recognized, compounded by the absence of routine polysomnographic assessment of children with moderate to severe heart failure. Building on much broader experience in the diagnosis and management of CSA-CSR in adult sleep medicine and our limited experience in a pediatric quaternary center, this paper will discuss the prevalence of CSA-CSR, its' treatment options, outcomes in children, and the potential future direction for research in this understudied area of pediatric sleep medicine.

[Is ASV therapy a positive airway pressure or ventilation therapy? A comparison of acid-base balance per day and under ASV]

The aim of this work was to determine whether therapy with adaptive support ventilation (ASV) leads to impairment of acid-base balance, in particular to hypocapnia and alkalosis. For this purpose, we measured the acid-base status (SBH) with carbon dioxide and oxygen partial pressure in arterialized blood (pCO₂ and pO₂), standard bicarbonate (SBC) and pH under spontaneous breathing during the day and under ASV at night. The trigger for this work was, among other things, the result of the SERVE-HF study, which found an increased risk of mortality in patients with heart failure and left ventricular ejection fraction <45% under ASV. There was a presumption of a device algorithm-based effect. The question was whether the minimum pressure support (PSmin) of 3 cmH₂O via respiratory alkalosis has a pro-arrhythmogenic effect (and causes higher mortality). A study of patients with treatment-emergent central sleep apnea (TECSA) and normal cardiac function comparing 4 ASV devices showed significantly higher ventilation with the device used in the study. So, this excessive ventilation could be generated by the device and not by class.

METHODS

A total of 226 patients who came to the follow-up of the ASV from 10/2018 to 03/2020; age 65.2±11.3 years, BMI 35.7±7.5 kg/m², service life 5530±5400 h, 5.6±2.5 h/d, PSmin 4.9±1.8 cmH₂O. None of the patients had heart failure (EF>45%). The majority underwent ASV because of TECSA, rarely a cardiac or other genesis.

RESULTS

In 29 patients (12.8%) hypocapnia with pCO₂ <36 mmHg was found in the morning.

CONCLUSION

Under ASV we could not determine any class effect of hypocapnia. 12.8% had hypocapnia, and in half of the cases it was severe necessitating modification of therapy. This can have different causes but there are no clear criteria. As there is a risk of hyperventilation, acid-base balance under ASV should be checked.

Abnormal Sleep-Related Breathing Related to Heart Failure

Sleep-disordered breathing (SDB) is highly prevalent in patients with heart failure (HF). Untreated obstructive sleep apnea (OSA) and central sleep apnea (CSA) in patients with HF are associated with worse outcomes. Detailed sleep history along with polysomnography (PSG) should be conducted if SDB is suspected in patients with HF. First line of treatment is the optimization of medical therapy for HF and if symptoms persist despite optimization of the treatment, positive airway pressure (PAP) therapy will be started to treat SDB. At present, there is limited evidence to prescribe any drugs for treating CSA in patients with HF. There is limited evidence for the efficacy of continuous positive airway pressure (CPAP) or adaptive servo-ventilation (ASV) in improving mortality in patients with heart failure with reduced ejection fraction (HFrEF). There is a need to perform well-designed studies to identify different phenotypes of CSA/OSA in patients with HF and to determine which phenotype responds to which therapy. Results of ongoing trials, ADVENT-HF, and LOFT-HF are eagerly awaited to shed more light on the management of CSA in patients with HF. Until then the management of SDB in patients with HF is limited due to the lack of evidence and guidance for treating SDB in patients with HF.

Extra-cardiac targets in the management of cardiometabolic disease: Device-based therapies

Heart failure (HF) does not occur in a vacuum and is commonly defined and exacerbated by its co‐morbid conditions. Neurohormonal imbalance and systemic inflammation are some of the key pathomechanisms of HF but also commonly encountered co‐morbidities such as arterial hypertension, diabetes mellitus, cachexia, obesity and sleep‐disordered breathing. A cornerstone of HF management is neurohormonal blockade, which in HF with reduced ejection fraction has been tied to a reduction in morbidity and mortality. Pharmacological treatment effective in patients with HF with reduced ejection fraction did not show substantial effects in HF with preserved ejection fraction. Here, we review novel device‐based therapies using neuromodulation of extra‐cardiac targets to treat cardiometabolic disease.

Sleepless nights and sleepy days: a qualitative study exploring the experiences of patients with chronic heart failure and newly verified sleep-disordered breathing

BACKGROUND

Sleep-disordered breathing, including obstructive sleep apnoea and central sleep apnoea, is a common disorder among patients with chronic heart failure. Obstructive sleep apnoea is often treated with continuous positive airway pressure, but central sleep apnoea lacks a clear treatment option. Knowledge of how sleep-disordered breathing is experienced (e.g. difficulties and care needs) and handled (e.g. self-care actions) by the patients is limited, but needed, to provide patient-centred care.

AIM

To explore how newly verified sleep-disordered breathing is experienced by patients with chronic heart failure.

METHODS

Data were collected through semi-structured interviews and analysed with qualitative content analysis. Seventeen participants (14 men, three women), mean age 60 years (range 41-80) diagnosed with chronic heart failure and objectively verified sleep-disordered breathing (nine obstructive, seven central and one mixed) were strategically selected from heart failure outpatient clinics at two Norwegian university hospitals.

RESULTS

Patients with chronic heart failure and newly verified sleep-disordered breathing (SDB) described experiences of poor sleep that had consequences for their daily life and their partners. Different self-care strategies were revealed, but they were based on 'common sense' and were not evidence-based. The awareness of having SDB was varied; for some, it gave an explanation to their trouble while others were surprised by the finding.

CONCLUSION

Patients with chronic heart failure and sleep-disordered breathing experienced reduced sleep quality, influencing their daily life. Possible underlying causes of disrupted sleep, such as sleep-disordered breathing, should be identified to establish proper patient-centred treatment strategies. There is a need for new strategies to approach patients with chronic heart failure (i.e. those with central sleep apnoea) who are not subject to continuous positive airway pressure treatment for their sleep-disordered breathing.

Sleep Apnea and Cardiovascular Disease: Lessons From Recent Trials and Need for Team Science

Emerging research highlights the complex interrelationships between sleep-disordered breathing and cardiovascular disease, presenting clinical and research opportunities as well as challenges. Patients presenting to cardiology clinics have a high prevalence of obstructive and central sleep apnea associated with Cheyne-Stokes respiration. Multiple mechanisms have been identified by which sleep disturbances adversely affect cardiovascular structure and function. Epidemiological research indicates that obstructive sleep apnea is associated with increases in the incidence and progression of coronary heart disease, heart failure, stroke, and atrial fibrillation. Central sleep apnea associated with Cheyne-Stokes respiration predicts incident heart failure and atrial fibrillation; among patients with heart failure, it strongly predicts mortality. Thus, a strong literature provides the mechanistic and empirical bases for considering obstructive sleep apnea and central sleep apnea associated with Cheyne-Stokes respiration as potentially modifiable risk factors for cardiovascular disease. Data from small trials provide evidence that treatment of obstructive sleep apnea with continuous positive airway pressure improves not only patient-reported outcomes such as sleepiness, quality of life, and mood but also intermediate cardiovascular end points such as blood pressure, cardiac ejection fraction, vascular parameters, and arrhythmias. However, data from large-scale randomized controlled trials do not currently support a role for positive pressure therapies for reducing cardiovascular mortality. The results of 2 recent large randomized controlled trials, published in 2015 and 2016, raise questions about the effectiveness of pressure therapies in reducing clinical end points, although 1 trial supported the beneficial effect of continuous positive airway pressure on quality of life, mood, and work absenteeism. This review provides a contextual framework for interpreting the results of recent studies, key clinical messages, and suggestions for future sleep and cardiovascular research, which include further consideration of individual risk factors, use of existing and new multimodality therapies that also address adherence, and implementation of trials that are sufficiently powered to target end points and to support subgroup analyses. These goals may best be addressed through strengthening collaboration among the cardiology, sleep medicine, and clinical trial communities.

Positive Airway Pressure Therapy for Hyperventilatory Central Sleep Apnea: Idiopathic, Heart Failure, Cerebrovascular Disease, and High Altitude

Central sleep apnea (CSA) and Hunter-Cheyne-Stokes breathing (HCSB) are caused by failure of the pontomedullary pacemaker generating breathing rhythm. CSA/HCSB may complicate several disorders causing recurrent arousals and desaturations. Common causes of CSA in adults are congestive heart failure, stroke, and chronic use of opioids; opioids have hypoventilatory effects. Diagnosis and treatment of hyperventilatory CSA may improve quality of life, and, when associated with heart failure or cerebrovascular disease, reduce morbidity and perhaps mortality.

Sleep-Disordered Breathing in Heart Failure - A Therapeutic Dilemma

Sleep-disordered breathing (SDB) occurs in approximately 50% of patients with reduced left ventricular ejection fraction receiving contemporary heart failure (HF) therapies. Obstructive (OSA) and central sleep apneas (CSA) interrupt breathing by different mechanisms but impose qualitatively similar autonomic, chemical, mechanical, and inflammatory burdens on the heart and circulation. Because contemporary evidence-based drug and device HF therapies have little or no mitigating effect on the acute or long-term consequences of such stimuli, there is a sound mechanistic rationale for targeting SDB to reduce cardiovascular event rates and prolong life. However, the promise of observational studies and randomized trials of small size and duration describing a beneficial effect of treating SDB in HF via positive airway pressure was not realized in 2 recent randomized outcome-driven trials: SAVE, which evaluated the cardiovascular effect of treating OSA in a cohort without HF, and SERVE-HF, which reported the results of a strategy of random allocation of minute-ventilation-triggered adaptive servo-ventilation (ASV) for HF patients with CSA. Whether effective treatment of either OSA or CSA improves the HF trajectory by reducing cardiovascular morbidity or mortality has yet to be definitively established. ADVENT-HF, designed to determine the effect of treating both CSA and non-sleepy OSA HF patients with a peak-airflow triggered ASV algorithm, could resolve this present clinical equipoise concerning the treatment of SDB.

Factors Contributing to Unintentional Leak During CPAP Treatment: A Systematic Review

CPAP is the first-line treatment for moderate to severe OSA syndrome. Up to 25% of patients with OSA syndrome discontinue CPAP treatment due to side effects. Unintentional leakage and its associated annoying consequences are the most frequently reported adverse effects of CPAP. Successive technological improvements have not succeeded in addressing this issue. A systematic review was conducted (1) to assess the impact of different technological advances on unintentional leaks and (2) to determine if any patient characteristics have already been identified as determinants of unintentional leakage. No CPAP modality was superior to another in reducing unintentional leaks and, surprisingly, oronasal masks were associated with higher unintentional leaks. Nasal obstruction, older age, higher BMI, central fat distribution, and male sex might be associated with an increased risk of unintentional leakage. Such leaks remain an important problem. Further studies are needed to improve the understanding of underlying clinical factors so that patients at risk of unintentional leaks may be identified and individualized solutions applied.