Effects of sacubitril-valsartan on central and obstructive apneas in heart failure patients with reduced ejection fraction

OBJECTIVE

This study aimed to evaluate the effect of sacubitril-valsartan (SV) on central apneas (CA) and obstructive apneas (OA) in patients with heart failure with reduced ejection fraction (HFrEF).

METHODS

In patients with HFrEF, SV initiation was titrated to the highest tolerable dosage. Patients were evaluated with portable apnea monitoring, echocardiography, and cardiopulmonary exercise testing at baseline and 3 months later.

RESULTS

Of a total of 18 patients, 9 (50%) had OA, 7 (39%) had CA, and 2 (11%) had normal breathing. SV therapy was related to a reduction in NT-pro BNP and an improvement in LV function after 3 months. Portable apnea monitoring revealed a significant decrease of the respiratory event index (REI) after treatment with SV (20 ± 23 events/h to 7 ± 7 events/h, p = 0.003). When subgrouping according to type of apneas, REI, and time spent below 90% saturation (T90) decreased in patients with CA and OA (all p < 0.05).

CONCLUSION

In this prospective study, SV treatment for 3 months in patients with CA and OA is associated with a significant decrease in REI.

Effect of antihypertensive medications on sleep status in hypertensive patients

Purpose

Antihypertensive medication is an effective way to control blood pressure. However, some studies reported that it may affect patients' sleep quality during the treatment. Due to the inconsistency of present results, a comprehensive systematic review and network meta-analysis are needed.

Methods

Electronic databases (MEDLINE, EMBASE, WEB OF SCIENCE, PUBMED) were searched up to April 10th, 2021 including no restriction of publication status. Randomized controlled trials (RCTs) or quasi-experimental studies or cohort studies were eligible. The network meta-analysis was used within a Bayesian framework.

Results

Finally, 16 publications (including 12 RCTs and 4 quasi-experimental studies) with 404 subjects were included in this study. Compared to placebo, the results of the network meta-analysis showed that diuretics were effective in improving sleep apnea with a mean difference (MD) of - 15.47 (95% confidence interval [CI]: - 23.56, - 6.59) which was consistent with the direct comparison result (MD: - 17.91; 95% CI - 21.60, - 14.23). In addition, diuretics were effective in increasing nocturnal oxygen saturation with an MD of 3.64 (95% CI 0.07, 7.46). However, the effects of β-blockers, calcium channel blockers, angiotensin-converting enzyme inhibitors, angiotensin-receptor blockers, and the others on sleep apnea were not statistically significant. Additionally, the effects of antihypertensive medication on the total sleep time (min), rapid eye movement (%), and sleep efficiency (%) were not statistically significant.

Conclusion

Our study found that diuretics could effectively reduce the severity of sleep apnea in hypertensive patients. However, the effects of antihypertensive drugs on sleep characteristics were not found.

Supplementary Information

The online version contains supplementary material available at 10.1007/s41105-022-00391-8.

Assessment of sleep disordered breathing in patients with heart failure

When to look for sleep disturbances in heart failure patients and how best to treat them: a practical and evidence-based expert opinion https://bit.ly/3LpCnNP.

Management of Obstructive Sleep Apnea in Patients With Heart Failure

Sleep apnea is traditionally classified as obstructive sleep apnea (OSA), which occurs when the upper airway collapses due to the relaxation of oropharyngeal musculature, and central sleep apnea occurs when the brainstem cannot stimulate breathing. Most sleep apnea in patients with heart failure (HF) results from coexisting OSA and central sleep apnea (CSA), or complex sleep apnea syndrome. OSA and CSA are common in HF and can be involved in its progression by exposure to the heart to intermittent hypoxia, increased preload and afterload, activating sympathetic, and decreased vascular endothelial function. A majority of treatments have been investigated in patients with CSA and HF; however, less or short-term randomized trials demonstrated whether treating OSA in patients with HF could improve morbidity and mortality. OSA could directly influence the patient's recovery. This review will focus on past and present studies on the various therapies for OSA in patients with HF and summarize CSA treatment options for reasons of reference and completeness. More specifically, the treatment covered include surgical and non-surgical treatments and reported the positive and negative consequences for these treatment options, highlighting possible implications for clinical practice and future research directions.

CARDIAC chronotropic effects of sleep-disordered breathing in patients with heart failure

It is still not known whether the oscillation in heart rate (HR) induced by sleep-disordered breathing (SDB) in patients with heart failure entails significant chronotropic effects. We hypothesised that since cyclical changes in ventilation and arterial blood gases during SDB affect HR through multiple and complexly interacting mechanisms characterised by large inter-subject variability, chronotropic effects may change from patient to patient. A total of 42 patients with moderate-to-severe chronic heart failure with systolic dysfunction underwent an in-hospital sleep study. Chronotropic effects of SDB were quantified by comparing the distribution of instantaneous HR during SDB with that during periods without SDB (noSDB) within the same night in each patient. Based on distribution changes from noSDB to SDB, 12, nine, 11, and 10 patients showed a significant tachycardic, bradycardic, tachycardic and bradycardic, and neither significant tachycardic nor significant bradycardic effect, respectively. Tachycardic and bradycardic effects were primarily due to an increase in the rate rather than in the magnitude of cyclical HR elevations and reductions, and were more prevalent and severe in patients with dominant obstructive and central events, respectively. The apnea-hypopnea index did not differ between groups. Conversely, the time spent with an oxygen saturation of <90% was greater in the tachycardic and tachycardic-bradycardic groups compared to the bradycardic group. These findings indicate that HR distribution changes induced by SDB can vary from patient to patient revealing four distinct and well-characterised chronotropic effects. These effects are related to the degree of hypoxic burden brought about by SDB and are affected by the type of sleep apnea (central/obstructive).

Sleep Apnea in Heart Failure

PURPOSE OF REVIEW

In this review, we discuss the current treatment options for sleep-disordered breathing (SDB) in patients with heart failure (HF). We address the role of positive airway pressure (PAP) devices and other emerging therapies. The review includes discussion of recent trials that reported negative consequences for the PAP devices in patients with heart failure.

RECENT FINDINGS

Optimal guideline-directed medical therapies of HF and PAP devices have been the mainstay treatments for HF patients with SDB. Recently, randomized controlled trials (RCTs) evaluated the effect of PAP on clinical outcomes in patients with cardiovascular (CV) disease and heart failure and found no benefit in decreasing fatal and non-fatal CV events. The Sleep Apnea Cardiovascular Endpoints (SAVE) trial evaluated continuous positive airway pressure (CPAP) ventilation in patients with CV disease and obstructive sleep apnea (OSA) and did not observe any improvement in CV effect. In patients with HF and central sleep apnea (CSA), adaptive servo-ventilation (ASV) was hypothesized to help HF outcomes, but the Adaptive Servo-Ventilation for Central Sleep Apnea in Systolic Heart Failure (SERVE-HF) trial did not show any mortality benefit. Instead, the trial suggested an increase in all-cause and CV mortality in the treatment arm. currently, studies have not shown the use of PAP therapy to improve any risks of CV outcomes or death in HF patients with sleep apnea, but some associations with improvements in symptoms from OSA have been observed.

Impact of sacubitril-valsartan combination in patients with chronic heart failure and sleep apnoea syndrome: the ENTRESTO-SAS study design

Aims

Sleep‐disordered breathing (SDB) is a highly prevalent co‐morbidity in patients with chronic heart failure (CHF) and can play a detrimental role in the pathophysiology course of CHF. However, the best way to manage SDB in CHF remains a matter of debate. Sacubitril–valsartan has been included in the 2016 European Society of Cardiology guidelines as an alternative to angiotensin‐converting enzyme inhibitors to further reduce the risk of progression of CHF, CHF hospitalization, and death in ambulatory patients. Sacubitril and valsartan are good candidates for correcting SDB of CHF patients because their known mechanisms of action are likely to counteract the pathophysiology of SDB in CHF.

Methods and results

The ENTRESTO‐SAS trial is a 3‐month, multicentric, prospective, open‐label real‐life cohort study. Patients eligible for sacubitril–valsartan treatment (i.e. adults with left ventricular ejection fraction ≤35%, who remain symptomatic despite optimal treatment with an angiotensin‐converting enzyme inhibitor, a beta‐blocker, and a mineralocorticoid receptor antagonist) will be evaluated before and after 3 months of treatment (nocturnal ventilatory polygraphy, echocardiography, laboratory testing, and quality‐of‐life and SDB questionnaires). The primary outcome is the change in the Apnoea–Hypopnoea Index, before and after 3 months of treatment. One hundred twenty patients are required to detect a significant 20% improvement of the Apnoea–Hypopnoea Index with a power of 90% at an alpha risk of 5%.

Conclusions

In the context of the SERVE‐HF study, physicians are waiting for new trials and alternative therapies. We sought to assess in the ENTRESTO‐SAS trial whether sacubitril–valsartan could improve the outcome of SDB in CHF patients.

Sleep-disordered breathing in heart failure: The state of the art after the SERVE-HF trial

Heart failure (HF) is one of the most prevalent conditions worldwide and despite therapeutic advances, its prognosis remains poor. Among the multiple comorbidities in HF, sleep-disordered breathing (SDB) is frequent and worsens the prognosis. Preliminary observational studies suggested that treatment of SDB could modify the prognosis of HF, and the issue has gained importance in recent years. The diagnosis of SDB is expensive, slow and suboptimal, and there is thus a need for screening devices that are easier to use and validated in this population. The first-line treatment involves optimization of medical therapy for heart failure. Continuous positive airway pressure (CPAP) is used in patients who mainly suffer from obstructive sleep apnea. In patients with predominantly central sleep apnea, CPAP is not sufficient and adaptive servo-ventilation (ASV), despite promising results in observational studies, showed no benefit in patients with symptomatic HF and reduced ejection fraction in the SERVE-HF randomized trial; on the contrary, there was unexpectedly increased mortality in the ASV group compared to controls, and so ASV is contraindicated in these patients, calling into question the definition and pathogenesis of SDB and risk stratification in these patients. There are many gaps in the evidence, and so further research is needed to better understand this issue: definitions, simple screening methods, and whether and how to treat SDB in patients with HF.

A novel method for the quantitative evaluation of diurnal respiratory instability in patients with heart failure: A pilot study

BACKGROUND

There is no established method to quantitatively measure the presence and the severity of respiratory instability (RI). The purpose of this pilot study was to propose a novel index of diurnal RI as a surrogate measure of clinical severity of heart failure (HF).

METHODS AND RESULTS

We prospectively enrolled 60 patients with symptomatic HF [70±14 years, 75% male, and New York Heart Association (NYHA) functional classes II-IV] who underwent right heart catheterization (RHC), and recorded diurnal respiration using a nasal pressure sensor during bed rest while awake within 2 days before or after RHC. Non-uniformity of the breath-by-breath respiratory slopes during 15min calculated as the ratio of peak expiratory amplitude to corresponding peak-to-peak interval was assessed by histogram-based frequency distribution measurement, and was defined as the "RI-index". The RI-index was significantly different among NYHA functional classes and was highest in NYHA class IV. The presence of atrial fibrillation (β coefficient: 0.300, p=0.01) and stroke volume index (β coefficient: -0.462, p<0.01) were independently associated with RI index among hemodynamic parameters. Furthermore, the high RI index above the median value was the independent predictor of the composite outcome of death from any cause, a life-threatening arrhythmia, and an unplanned hospitalization for worsening HF.

CONCLUSIONS

The RI index stratified functional severity of HF well, and was a significant independent predictor of poor outcomes.

Heart failure and sleep disordered breathing

Sleep-disordered breathing (SDB) is frequently observed in patients with heart failure (HF), and complex pathologic conditions exist between both conditions. In this review article, we describe the characteristics of SDB complicated with HF, the prognostic impact of SDB in HF patients, and the favorable effects of positive airway pressure in HF patients with SDB.

Effect of Antihypertensive Medications on the Severity of Obstructive Sleep Apnea: A Systematic Review and Meta-Analysis

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) is an independent risk factor for hypertension (HTN). Increasing evidence from animal and human studies suggests that HTN exacerbates OSA. We performed a systematic review and meta-analysis of studies evaluating the effect of anti-hypertensive medications on the severity of OSA.

METHODS

A literature search of PubMed and Embase was done using search concepts of OSA, HTN, and drug classes used to treat HTN. Studies that reported changes in the severity of OSA objectively by using apnea-hypopnea index (AHI) or respiratory disturbance index (RDI) were included. Pooled mean difference estimates were calculated. Tests for heterogeneity, publication bias, and subgroup sensitivity analysis were conducted.

RESULTS

Of 27,376 studies screened, only 11 met inclusion criteria, including 5 randomized controlled trials and 6 single-arm prospective trials. The pooled mean difference estimate (95% confidence interval [CI]), based on a random-effects model, was -5.69 (95% CI -10.74 to -0.65), consistent with an overall decrease in AHI or RDI attributable to antihypertensive medications. The effect size was even more pronounced, -14.52 (95% CI -25.65 to -3.39), when only studies using diuretics were analyzed. There was no significant heterogeneity or publication bias among the studies. Meta-regression indicated neither age, baseline AHI, nor change in systolic/diastolic blood pressure influenced the results.

CONCLUSIONS

Collectively, findings from these relatively small, short-term studies tend to support the contention that treatment with antihypertensive agents confers a statistically significant, albeit small, reduction in the severity of OSA, which may be more pronounced with the use of diuretics.

Effect of cardiac pacing on sleep-related breathing disorders: a systematic review

Sleep-related breathing disorders are commonly encountered in the middle-aged population, negatively affecting quality of life. Central sleep apnea is associated with congestive heart failure, whereas obstructive sleep apnea is related to different pathophysiologic mechanisms, such as the total or partial occlusion of upper airway tract. Both sleep-related disorders have been associated with increased morbidity, and hence, they have been a target of several treatment strategies. The aim of this systematic review is to evaluate the effect of different types of cardiac pacing on sleep-related breathing disorders in patients with or without heart failure. The PubMed and Cochrane Central Register of Controlled Trials were examined from April 2015 to January 2016. Of the initial 360 studies, 22 eligible trials were analyzed. The included studies were classified according to the type of sleep disorder and the intervention undertaken. The evidence shows that cardiac resynchronization therapy but not atrial overdrive pacing can reduce apneic events in central sleep apnea patients. However, their effect on obstructive sleep apnea is controversial. It can be assumed that pacing cannot be used alone as treatment of sleep-related breathing disorders. Further research is needed in order to elucidate the effect of these interventions in sleep apnea patients.

Sleep-disordered Breathing in Heart Failure - Current State of the Art

Sleep-disordered breathing (SDB), either obstructive sleep apnoea (OSA) or central sleep apnoea (CSA)/Cheyne-Stokes respiration (CSR) and often a combination of the two, is highly prevalent in patients with heart failure (HF), is associated with reduced functional capacity and quality of life, and has a negative prognostic impact. European HF guidelines identify that sleep apnoea is of concern in patients with HF. Continuous positive airway pressure is the treatment of choice for OSA, and adaptive servoventilation (ASV) appears to be the most consistently effective therapy for CSA/CSR while also being able to treat concomitant obstructive events. There is a growing body of evidence that treating SDB in patients with HF, particularly using ASV for CSA/CSR, improves functional outcomes such as HF symptoms, cardiac function, cardiac disease markers, exercise tolerance and quality of life. However, conflicting results have been reported on 'hard' outcomes such as mortality and healthcare utilisation, and the influence of effectively treating SDB, including CSA/CSR, remains to be determined in randomised clinical trials. Two such trials (SERVE-HF and ADVENT-HF) in chronic stable HF and another in post-acute decompensated HF (CAT-HF) are currently underway.

Impact of predischarge nocturnal pulse oximetry (sleep-disordered breathing) on postdischarge clinical outcomes in hospitalized patients with left ventricular systolic dysfunction after acute decompensated heart failure

Stratifying patients at a high risk for readmission and mortality before their discharge after acute decompensated heart failure (ADHF) is important. Although sleep-disordered breathing (SDB) is prevalent in patients with chronic heart failure, only few studies have investigated the impact of SDB on hospitalized patients with left ventricular (LV) systolic dysfunction after ADHF. Thus, we assessed the prevalence of SDB using nocturnal pulse oximetry and the relation between SDB and clinical events in this patient group. One hundred consecutive patients with LV systolic dysfunction who were hospitalized for ADHF were enrolled in the study. Predischarge nocturnal oximetry was performed to determine if they had SDB (defined as an oxygen desaturation index of ≥5 events/hour with ≥4% decrease in saturation level). Data on death and readmission for ADHF were collected. Forty-one patients had SDB. Complete outcome data were collected in the mean follow-up period of 14.2 months during which 33 events occurred. On multivariate Cox proportional hazards regression analysis, the presence of SDB was a significant independent predictor of postdischarge readmission and mortality (hazard ratio 2.93, p = 0.006). In conclusion, SDB, as determined by predischarge nocturnal oximetry, is prevalent and is an independent predictor of the combined end point of readmission and mortality in hospitalized patients with LV systolic dysfunction after ADHF.

Therapy for sleep hypoventilation and central apnea syndromes

OPINION STATEMENT

• Primary Central Sleep Apnea (CSA): We would recommend a trial of Positive Airway Pressure (PAP), acetazolamide, or zolpidem based on thorough consideration of risks and benefits and incorporation of patient preferences.• Central Sleep Apnea Due to Cheyne-Stokes Breathing Pattern in Congestive Heart Failure (CSR-CHF): We would recommend PAP devices such as continuous positive airway pressure (CPAP) or adaptive servo-ventilation (ASV) to normalize sleep-disordered breathing after optimizing treatment of heart failure. Oxygen may also be an effective therapy. Acetazolamide and theophylline may be considered if PAP or oxygen is not effective.• Central Sleep Apnea due to High-Altitude Periodic Breathing: We would recommend descent from altitude or supplemental oxygen. Acetazolamide may be used when descent or oxygen are not feasible, or in preparation for ascent to high altitude. Slow ascent may be preventative.• Central Sleep Apnea due to Drug or Substance: If discontinuation or reduction of opiate dose is not feasible or effective, we would recommend a trial of CPAP, and if not successful, treatment with ASV. If ASV is ineffective or if nocturnal hypercapnia develops, bilevel positive airway pressure-spontaneous timed mode (BPAP-ST) is recommended.• Obesity hypoventilation syndrome: We would recommend an initial CPAP trial. If hypoxia or hypercapnia persists on CPAP, BPAP, BPAP-ST or average volume assured pressure support (AVAPS™) is recommended. Tracheostomy with nocturnal ventilation should be considered when the above measures are not effective. Weight loss may be curative.• Neuromuscular or chest wall disease: We would recommend early implementation of BPAP-ST based on thorough consideration of risks and benefits and patient preferences. AVAPS™ may also be considered. We recommend close follow up due to disease progression.

Adaptive servo ventilation improves Cheyne-Stokes respiration, cardiac function, and prognosis in chronic heart failure patients with cardiac resynchronization therapy

BACKGROUND

Cheyne-Stokes respiration (CSR-CSA) is often observed in patients with chronic heart failure (CHF). Although cardiac resynchronization therapy (CRT) is effective for CHF patients with left ventricular dyssynchrony, it is still unclear whether adaptive servo ventilation (ASV) improves cardiac function and prognosis of CHF patients with CSR-CSA after CRT.

METHODS AND RESULTS

Twenty two patients with CHF and CSR-CSA after CRT defibrillator (CRTD) implantation were enrolled in the present study and randomly assigned into two groups: 11 patients treated with ASV (ASV group) and 11 patients treated without ASV (non-ASV group). Measurement of plasma B-type natriuretic peptide (BNP) levels (before 3, and 6 months later) and echocardiography (before and 6 months) were performed in each group. Patients were followed up to register cardiac events (cardiac death and re-hospitalization) after discharge. In the ASV group, indices for apnea-hypopnea, central apnea, and oxyhemoglobin saturation were improved on ASV. BNP levels, cardiac systolic and diastolic function were improved with ASV treatment for 6 months. Importantly, the event-free rate was significantly higher in the ASV group than in the non-ASV group.

CONCLUSIONS

ASV improves CSR-CSA, cardiac function, and prognosis in CHF patients with CRTD. Patients with CSR-CSA and post CRTD implantation would get benefits by treatment with ASV.

Overdrive ventricular pacing in pacemaker recipients with permanent atrial fibrillation and sleep apnea

STUDY OBJECTIVES

Cardiac pacing is ineffective in obstructive sleep apnea (SA), but it can alleviate central SA/Cheyne-Stokes respiration (CSA) in patients with heart failure (HF). We examined whether overnight overdrive ventricular pacing (OVP) has an effect on SA in pacemaker recipients with permanent atrial fibrillation (AF).

METHODS

An apnea-hypopnea index (AHI) ≥ 15 was confirmed in 28/38 patients screened by finger pulse oximetry during overnight ventricular pacing at a backup rate of 40 bpm (BUV40). These patients (23 men, 77.9 ± 7.6 y, BMI 27.6 ± 5.1 kg/m(2)) were randomly assigned to 2 consecutive nocturnal ventilation polygraphies with BUV40 versus OVP at 20 bpm above the mean nocturnal heart rate observed during screening.

RESULTS

During BUV40 versus OVP, (1) mean heart rate was 49 ± 8 versus 71 ± 8 bpm (p < 0.0001) and percent ventricular pacing 36% ± 38% versus 96% ± 6% (p < 0.0001); (2) AHI was 35.4 ± 11.9 versus 32.5 ± 15.5 (p = ns), central AHI 23.9 ± 11.8 versus 19.1 ± 12.7 (p < 0.001), and obstructive AHI 11.6 ± 13.1 versus 13.5 ± 15.9 (p = ns). In 15/28 patients without HF, mean left ventricular ejection fraction (LVEF) was 51% ± 17%, AHI was 37.6 ± 11.0 during BUV40 and 39.0 ± 11.5 during OVP, versus 32.8 ± 12.9 and 24.9 ± 16.5 in 13/28 patients with HF (p = 0.02) and mean LVEF 35% ± 15% (p = 0.01). Between the 2 subgroups, (1) central AHI was 23.6 ± 12.4 during BUV40 and 21.5 ± 14.0 during OVP versus 24.1 ± 11.6 and 16.2 ± 10.7 (p = 0.05); (2) obstructive AHI was 14.0 ± 13.7 during BUV40 and 17.6 ± 16.5 during OVP versus 8.8 ± 12.3 and 8.7 ± 14.3 (p = ns).

CONCLUSIONS

The prevalence of SA, predominantly central, was high in our pacemaker recipients with permanent AF. In those with HF, a single overnight OVP resulted in modest improvement in central events.

Dynamic CO₂ inhalation: a novel treatment for CSR-CSA associated with CHF

BACKGROUND

Cheyne-Stokes respiration with central sleep apnea (CSR-CSA) is very common in patients with chronic congestive heart failure (CHF). A current concept of the key pathophysiological mechanism leading to CSR-CSA is a fluctuation of PaCO2 below and above the apneic threshold. A number of therapeutic approaches for CSR-CSA have been proposed-all with varying success, some of which include various modes of positive airway pressure among other strategies. However, CO2 oscillations seen in CSR-CSA have yet to be looked at as a specific therapeutic target by current treatments.

DISCUSSION

Previous studies have shown that delivery of constant CO2 is efficacious in eliminating CSR-CSA by raising PaCO2, but there are serious concerns about the potential side effects, such as unwanted elevations in ventilation, work of breathing, and sympathetic nerve activity (SNA), and consequently CO2 inhalation therapy has not been recommended as a routine option for therapy. However, recent new studies into CO2 inhalation therapy have been made that may reshape its role as therapeutic. In this review, we will focus on the recent developments of administration of dynamic CO2 in the management of CSR-CSA in CHF patients.

Importance and management of chronic sleep apnoea in cardiology

Sleep apnoea is a common, yet underestimated, chronic disorder with a major impact on morbidity and mortality in the general population. It is quickly becoming recognized as an independent risk factor for cardiovascular impairment. Hypertension, coronary artery disease, diabetes, cardiovascular rhythm and conduction abnormalities, cerebrovascular disease, and heart failure have all been linked to this syndrome. This review will explore the critical connection between sleep apnoea and chronic cardiovascular diseases while highlighting established and emerging diagnostic and treatment strategies.

The treatment of central sleep apnea syndromes in adults: practice parameters with an evidence-based literature review and meta-analyses

The International Classification of Sleep Disorders, Second Edition (ICSD-2) distinguishes 5 subtypes of central sleep apnea syndromes (CSAS) in adults. Review of the literature suggests that there are two basic mechanisms that trigger central respiratory events: (1) post-hyperventilation central apnea, which may be triggered by a variety of clinical conditions, and (2) central apnea secondary to hypoventilation, which has been described with opioid use. The preponderance of evidence on the treatment of CSAS supports the use of continuous positive airway pressure (CPAP). Much of the evidence comes from investigations on CSAS related to congestive heart failure (CHF), but other subtypes of CSAS appear to respond to CPAP as well. Limited evidence is available to support alternative therapies in CSAS subtypes. The recommendations for treatment of CSAS are summarized as follows: CPAP therapy targeted to normalize the apnea-hypopnea index (AHI) is indicated for the initial treatment of CSAS related to CHF. (STANDARD)Nocturnal oxygen therapy is indicated for the treatment of CSAS related to CHF. (STANDARD)Adaptive Servo-Ventilation (ASV) targeted to normalize the apnea-hypopnea index (AHI) is indicated for the treatment of CSAS related to CHF. (STANDARD)BPAP therapy in a spontaneous timed (ST) mode targeted to normalize the apnea-hypopnea index (AHI) may be considered for the treatment of CSAS related to CHF only if there is no response to adequate trials of CPAP, ASV, and oxygen therapies. (OPTION)The following therapies have limited supporting evidence but may be considered for the treatment of CSAS related to CHF after optimization of standard medical therapy, if PAP therapy is not tolerated, and if accompanied by close clinical follow-up: acetazolamide and theophylline. (OPTION)Positive airway pressure therapy may be considered for the treatment of primary CSAS. (OPTION)Acetazolamide has limited supporting evidence but may be considered for the treatment of primary CSAS. (OPTION)The use of zolpidem and triazolam may be considered for the treatment of primary CSAS only if the patient does not have underlying risk factors for respiratory depression. (OPTION)The following possible treatment options for CSAS related to end-stage renal disease may be considered: CPAP, supplemental oxygen, bicarbonate buffer use during dialysis, and nocturnal dialysis. (OPTION) .

Effects of Heart Failure and its Pharmacological Management on Sleep

Heart failure (HF) patients have a high prevalence of disturbed sleep. Optimal pharmacological management of HF includes the use of angiotensin converting enzyme inhibitors and β-blockers, which have been associated with decreased severity of central sleep apnea, which is likely secondary to improvements in cardiac performance. There is also evidence, however, indicating that other pharmacological treatments for HF might adversely affect sleep. This brief review introduces the topic of disturbed sleep in HF and examines the extent to which its standard pharmacological management impacts sleep quality.

Sleep disordered breathing in patients with heart failure: pathophysiology and management

OPINION STATEMENT

Sleep disordered breathing (SDB) is common in heart failure patients across the range of ejection fractions and is associated with adverse prognosis. Although effective pharmacologic and device-based treatment of heart failure may reduce the frequency or severity of SDB, heart failure treatment alone may not be adequate to restore normal breathing during sleep. Continuous positive airway pressure (CPAP) is the major treatment for SDB in heart failure, especially if obstructive rather than central sleep apnea (CSA) predominates. Adequate suppression of CSA by PAP is associated with a heart transplant-free survival benefit, although randomized trials are ongoing. Bilevel PAP (BPAP) may be as effective as CPAP in treating SDB and may be preferable over CPAP in patients who experience expiratory pressure discomfort. Adaptive (or auto) servo-ventilation (ASV), which adjusts the PAP depending on the patient's airflow or tidal volume, may be useful in congestive heart failure patients if CPAP is ineffective. Other therapies that have been proposed for SDB in congestive heart failure include nocturnal oxygen, CO(2) administration (by adding dead space), theophylline, and acetazolamide; most of which have not been systematically studied in outcome-based prospective randomized trials.

Adaptive servo ventilation improves cardiac dysfunction and prognosis in chronic heart failure patients with Cheyne-Stokes respiration

Cheyne-Stokes respiration (CSR) is often observed in patients with chronic heart failure (CHF). Although adaptive servo ventilation (ASV) is effective for CSR, it remains unclear whether ASV improves the cardiac function and prognosis of patients with CHF and CSR.Sixty patients with CHF and CSR (mean left ventricular ejection fraction 38.7%, mean apnea hypopnea index 36.8 times/hour, mean central apnea index 19.1 times/hour) were enrolled in this study. Patients were divided into two groups: 23 patients treated with ASV (ASV group) and 37 patients treated without ASV (Non-ASV group). Measurement of plasma B-type natriuretic peptide (BNP) levels and echocardiography were performed before, 3 and 6 months after treatments in each group. Patients were followed-up for cardiac events (cardiac death and re-hospitalization) after discharge. In the ASV group, NYHA functional class, BNP levels, cardiac systolic and diastolic function were significantly improved with ASV treatment for 6 months. In contrast, none of these parameters changed in the Non-ASV group. Importantly, Kaplan-Meier analysis clearly demonstrated that the event-free rate was significantly higher in the ASV group than in the Non-ASV group.Adaptive servo ventilation improves cardiac function and prognosis in patients with chronic heart failure and Cheyne-Stokes respiration.

Treatment options in Cheyne-Stokes respiration

About half of the patients suffering from heart failure present with sleep-disordered breathing. In most cases obstructive and central breathing disturbances (including Cheyne-Stokes respiration [CSR]) coexist. CSR is defined by a waxing and waning pattern of the tidal volume. While its pathophysiology has not been elucidated completely, increased ventilatory sensitivity for CO2 and therefore an imbalance of the respiratory drive and effort, a chronic hyperventilatory state, and changes of the apnoeic threshold are considered to play a relevant role. However, CSR in heart failure impairs survival and quality of life of the patients and is therefore a major challenge of respiratory sleep medicine. If CSR persists despite optimal medical and interventional therapy of the underlying cardiac disorder, oxygen supply, continuous positive airway pressure (CPAP), and bilevel pressure are often trialled. However, there is insufficient evidence to recommend oxygen or bilevel treatment. CPAP has proven to improve left ventricular function. In addition, retrospective analyses suggested a reduction of mortality under CPAP in heart failure patients with CSR. However, these findings could not be reproduced in the prospective controlled CanPAP trial. More recently, adaptive servoventilation (ASV) has been introduced for treatment of CSR or coexisting sleep-related breathing disorders. ASV devices aim at counterbalancing the ventilatory overshoot and undershoot by applying variable pressure support with higher tidal volume (TV) during hypoventilation and reduced TV during hyperventilation. ASV has proven to be superior to CPAP but the long-term efficacy and the influences on cardiac parameters and survival are still under investigation.

Differential effects of carvedilol and metoprolol on renal function in patients with heart failure

BACKGROUND

The aim of the present study was to verify the effects of beta-blockers on renal function in patients with heart failure (HF).

METHODS AND RESULTS

A total of 40 patients with HF (New York Heart Association class, II-III) were enrolled, who had beta-blocker therapy initiated with carvedilol (n=23) or metoprolol (n=17). The changes in renal and cardiac function were retrospectively analyzed over 16 weeks. The study population was divided into 2 groups according to the median baseline (65.9 ml/min) of estimated glomerular filtration rate (eGFR) calculated by the Modification of Diet in Renal Disease formula. eGFR significantly decreased in the higher eGFR group (P=0.04), but did not in the lower eGFR group. Left ventricular ejection fraction significantly increased in both groups with lower eGFR (P=0.01) and higher eGFR (P<0.01). There was an interaction between plasma norepinephrine concentration and eGFR in terms of beta-blocker treatment (P=0.02, ANOVA). eGFR significantly decreased in patients who received metoprolol (from 75.7+/-33.5 to 59.5+/-20.0 mlxmin(-1).1.73 m(-2), P<0.01), but did not change in those who received carvedilol (from 67.1+/-27.7 mlxmin(-1).1.73 m(-2) to 65.6+/-23.2 mlxmin(-1).1.73 m(-2)).

CONCLUSIONS

Beta-blockers preserved renal function in HF patients with lower baseline eGFR, but not in those with higher baseline eGFR. Carvedilol may be preferable to metoprolol to prevent the development of chronic kidney disease during beta-blocker therapy for HF.

Sleep in congestive heart failure

Breathing disorders during sleep are common in congestive heart failure (CHF). Sleep-disordered breathing (SDB) in CHF can be broadly classified as 2 types: central sleep apnea with Cheyne-Stokes breathing, and obstructive sleep apnea. Prevalence of SDB ranges from 47% to 76% in systolic CHF. Treatment of SDB in CHF may include optimization of CHF treatment, positive airway pressure therapy, and other measures such as theophylline, acetazolamide, and cardiac resynchronization therapy. Periodic limb movements are also common in CHF.

Clinical updates on carvedilol: a first choice beta-blocker in the treatment of cardiovascular diseases

IMPORTANCE OF THE FIELD

Carvedilol, a non-selective beta-blocker, has recently drawn attention because of its therapeutic benefits over other prescribed analogues for the treatment of cardiovascular diseases (CVDs).

AREAS COVERED IN THIS REVIEW

The present review attempts to present the clinical efficacy of carvedilol in comparison to other available beta-blockers. The literature search was carried out in three electronic databases (Unbound Medline, Pubmed and Sciencedirect) and internet search engines (Scirus and Google Scholar) without time constraints to ensure maximum literature coverage.

WHAT THE READER WILL GAIN

A relatively large number of comparative studies have revealed that carvedilol has advantage over traditional beta-blockers with respect to hemodynamic and metabolic effects, due to its unique non-selective alpha-/beta-adrenoceptor affinity. Such results indicate its safe and effective therapeutic application particularly in patients with complicated CVDs, even in pediatric and geriatric patients.

TAKE HOME MESSAGE

The therapeutic profile of carvedilol indicates its suitability for treatment of complicated CVDs than other non-selective beta-blockers. However, there is a limitation in terms of its dose due to its low bioavailability (approximately 25%). Therefore, there is still need for bioavailability enhancement and dose reduction to further improve the therapeutic efficacy of the drug.

Comparative effects of carvedilol vs bisoprolol for severe congestive heart failure

BACKGROUND

Although carvedilol and bisoprolol are effective medicines for the treatment of patients with heart failure (HF), only a few reports have compared their effects. This study was designed to compare the effects of them in patients with severe HF.

METHODS AND RESULTS

A total of 655 consecutive patients with HF, categorized as New York Heart Association Class 3 or 4, were retrospectively investigated. Of these patients, 217 were administered beta-blockers after admission and were divided into 2 groups (carvedilol, n=110; bisoprolol, n=107). No significant differences were observed in their characteristics between the 2 groups prior to the introduction of the beta-blockers. After 18 months of follow-up, there were no significant differences in the survival and cardiac event-free rates between the 2 groups. In contrast, there were several significant differences in patients with atrial fibrillation (AF) (carvedilol, n=40; bisoprolol, n=43). The percent changes in heart rate and brain natriuretic peptide level improved significantly in the bisoprolol group than in the carvedilol group. Furthermore, more patients in the bisoprolol group were defibrillated from AF to sinus rhythm than those in the carvedilol group (48% vs 16%; P=0.03).

CONCLUSIONS

Our data suggest that the 2 beta-blockers are equally effective in the improvement of severe HF, but bisoprolol shows favorable effects in patients with AF.

Valve repair improves central sleep apnea in heart failure patients with valvular heart diseases

BACKGROUND

Recent studies suggest that treatment of heart failure (HF) could improve cardiac function and sleep apnea syndrome (SAS), but it is unknown how cardiac surgery may affect SAS in HF patients. Relationships between HF with valvular heart diseases and 2 types of SAS (obstructive sleep apnea (OSA) and central sleep apnea (CSA)) were examined. The effects of valve repair surgery on OSA and CSA was also investigated.

METHODS AND RESULTS

Polysomnography, echocardiography and right cardiac catheterization were used to study 150 severe HF patients with mitral valvular and/or aortic valvular diseases. Significant associations between SAS and age, gender, body mass index, or hypertension were observed. The value of the CSA-apnea index (AI) was significantly correlated with pulmonary capillary wedge pressure (PCWP) and mean pulmonary artery pressure (PAP). These associations were not identified for OSA-AI. Valve repair surgery was used to treat 74 patients with severe SAS. The treatment led to a significant improvement in PCWP and mean PAP, and CSA-AI, but not in OSA-AI.

CONCLUSIONS

These findings suggest close associations between CSA and cardiac function in HF patients with valvular heart diseases. Furthermore, improvement of cardiac function with valvular surgery reduces the severity of CSA in HF patients with valvular heart diseases.

In-hospital testing for sleep-disordered breathing in hospitalized patients with decompensated heart failure: report of prevalence and patient characteristics

BACKGROUND

Sleep-disordered breathing (SDB) is present in more than 50% of ambulatory patients with chronic heart failure. The prevalence and type of SDB in hospitalized patients with acutely decompensated heart failure (ADHF) are not known.

METHODS AND RESULTS

In-hospital sleep studies were performed on consecutive patients with ADHF who were not previously tested for SDB. A total of 395 consecutive patients with ADHF underwent successful sleep study recording during hospitalization. A total of 298 patients (75%, 95% CI [71-80%] had SDB; of these, 226 (57%, 95% CI [52-62]) had predominantly obstructive SDB and 72 (18%, 95% CI [14-22]) had predominantly central SDB. Only 25% (95% CI 20-29%) of patients were free of SDB. Validation polysomnography between 6 and 8 weeks after discharge on a subgroup of unselected patients with obstructive SDB revealed a 100 % positive predictive value (95% CI 94-100%) for obstructive sleep apnea (OSA).

CONCLUSIONS

Similar to stable chronic heart failure, ADHF is associated with a high prevalence of SDB. The prevalence of predominantly obstructive SDB exceeded that of predominantly central SDB in ADHF patients. The presence of obstructive SDB during hospitalization predicted a diagnosis of OSA on polysomnography.