Relation of natriuretic peptide concentrations to central sleep apnea in patients with heart failure

Effects of ANP and BNP on the generation of respiratory rhythms in brainstem-spinal cord preparation isolated from newborn rats

Natriuretic peptides (NPs) are a family of peptide hormones produced in cardiac muscle cells and consist mainly of three types: atrial NP (ANP), B-type (or brain) NP (BNP), and C-type NP. We herein report the effects of ANP and BNP on central respiratory activity in brainstem-spinal cord preparation isolated from newborn rats. Bath application of these peptides (100 nM) induced a weak transient depression of the respiratory rhythm followed by recovery. Respiratory-related neurons in the rostral ventrolateral medulla showed a tendency for transient hyperpolarization followed by recovery during the application of ANP or BNP. The application of a membrane-permeable cGMP, 8-Br-cGMP (10 or 20 μM), did not induce significant effects on respiratory rhythm, suggesting no involvement of guanylyl cyclase in effects of ANP or BNP. We also examined effects of BNP on respiratory depression induced by the sedative dexmedetomidine, which exerts an inhibitory influence on respiratory rhythm. When pretreated with 50 nM BNP, the inhibitory effect of 100 nM dexmedetomidine was significantly reduced. Our findings suggest that ANP and BNP act as mild excitatory agents with sustained effects on respiratory rhythm after an initial transient depression.

Obese Patients Experience More Severe CSA than Non-Obese Patients

Objective: To investigate whether central sleep apnea (CSA) is associated with an increased risk of obesity. Materials and methods: From 1 January 2000 to 31 December 2015, we screened 24,363 obese patients from the 2005 longitudinal health insurance database, which is part of the Taiwan National Health Insurance Research Database. From the same database, 97,452 non-obese patients were also screened out. Age, gender, and index dates were matched. Multiple logistic regression was used to analyze the previous exposure risk of obese and CSA patients. A p-value of <0.05 was considered significant. Results: Obese patients were more likely to be exposed to CSA than non-obese patients would (AOR = 2.234, 95% CI = 1.483–4.380, p < 0.001). In addition, the closeness of the exposure time to the index time is positively correlated with the severity of obesity and has a dose–response effect (CSA exposure < 1 year, AOR = 2.386; CSA exposure ≥ 1 year and <5 years, AOR = 1.725; CSA exposure time ≥ 5 years, AOR = 1.422). The CSA exposure time of obese patients was 1.693 times that of non-obese patients. Longer exposure time is associated with more severe obesity and has a dose-response effect (CSA exposure < 1 year, AOR = 1.420; CSA exposure ≥ 1 year and <5 years, AOR = 2.240; CSA ≥ 5 years, AOR = 2.863). Conclusions: In this case-control study, patients with CSA had a significantly increased risk of obesity. Long-term exposure to CSA and obesity is more likely and has a dose-response effect.

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

STUDY OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Current Drug Treatment Strategies for Atrial Fibrillation and TASK-1 Inhibition as an Emerging Novel Therapy Option

Atrial fibrillation (AF) is the most common sustained arrhythmia with a prevalence of up to 4% and an upwards trend due to demographic changes. It is associated with an increase in mortality and stroke incidences. While stroke risk can be significantly reduced through anticoagulant therapy, adequate treatment of other AF related symptoms remains an unmet medical need in many cases. Two main treatment strategies are available: rate control that modulates ventricular heart rate and prevents tachymyopathy as well as rhythm control that aims to restore and sustain sinus rhythm. Rate control can be achieved through drugs or ablation of the atrioventricular node, rendering the patient pacemaker-dependent. For rhythm control electrical cardioversion and pharmacological cardioversion can be used. While electrical cardioversion requires fasting and sedation of the patient, antiarrhythmic drugs have other limitations. Most antiarrhythmic drugs carry a risk for pro-arrhythmic effects and are contraindicated in patients with structural heart diseases. Furthermore, catheter ablation of pulmonary veins can be performed with its risk of intraprocedural complications and varying success. In recent years TASK-1 has been introduced as a new target for AF therapy. Upregulation of TASK-1 in AF patients contributes to prolongation of the action potential duration. In a porcine model of AF, TASK-1 inhibition by gene therapy or pharmacological compounds induced cardioversion to sinus rhythm. The DOxapram Conversion TO Sinus rhythm (DOCTOS)-Trial will reveal whether doxapram, a potent TASK-1 inhibitor, can be used for acute cardioversion of persistent and paroxysmal AF in patients, potentially leading to a new treatment option for AF.

[Sleep disordered breathing in patients with chronic heart failure: prognosis and management]

Sleep disordered breathing is a frequent comorbidity (50-75%) in patients with chronic heart failure, but it is usually underestimated. This review analyzes sleep disordered breathing in patients with chronic heart failure, demonstrates pathogenetic relationships and the prognostic role of sleep apnea. The authors present modern treatment options for sleep apnea in this cohort (from non-invasive ventilation to implantable devices), highlight the role of drug therapy and outline perspectives of different treatment approaches. This clinical problem is designated as multidisciplinary, which requires a dialogue between researchers and doctors of various specialties to organize comprehensive effective care for this cohort of patients.

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.

Low leptin concentration may identify heart failure patients with central sleep apnea

Low leptin concentration has been shown to be associated with central sleep apnea in heart failure patients. We hypothesized that low leptin concentration predicts central sleep apnea. Consecutive ambulatory New York Heart Association (NYHA) classes I-IV heart failure patients were studied prospectively, including measurement of serum leptin, echocardiography and polysomnography. Sleep apnea was defined by type (central/mixed/obstructive) and by apnea-hypopnea index ≥5 by polysomnography. Subjects were divided into four groups by polysomnography: (1) central sleep apnea, (2) mixed apnea, (3) no apnea and (4) obstructive sleep apnea. Fifty-six subjects were included. Eighteen subjects were diagnosed with central sleep apnea, 15 with mixed apnea, 12 with obstructive apnea and 11 with no sleep apnea. Leptin concentration was significantly lower in central sleep apnea compared to obstructive apnea (8 ± 10.7 ng mL^-1 versus 19.7 ± 14.7 ng mL^-1 , P ˂ 0.01) or no sleep apnea (8 ± 10.7 ng mL^-1 versus 17.1 ± 8.4 ng mL^-1 , P ˂ 0.01). Logistic regression showed leptin to be associated independently with central sleep apnea [odds ratio (OR): 0.19; 95% confidence interval (CI): 0.06-0.62; area under the curve (AUC): 0.80, P < 0.01]. For the detection of central sleep apnea, a cut-off value for leptin concentration 5 ng mL^-1 yielded a sensitivity of 50% and specificity of 89%. In conclusion, a low leptin concentration may have utility for the screening of heart failure patients for central sleep apnea.

Potential Expanded Indications for Neprilysin Inhibitors

PURPOSE OF REVIEW

The goal of this article is to review potential expanded indications for neprilysin inhibitors. This article reviews the rationale and design for ongoing and future trials of sacubitril/valsartan in cardiovascular and non-cardiovascular disease.

RECENT FINDINGS

Randomized trial data are lacking for use of sacubitril/valsartan in acute heart failure and advanced heart failure. Mechanistic data from animal studies suggest a role for neprilysin inhibition in the treatment of post-myocardial infarction systolic dysfunction and heart failure with preserved ejection fraction. Beyond the cardiovascular system, renal and neurological function may be impacted by neprilysin inhibition. Forthcoming randomized trials will address the clinical impact of sacubitril/valsartan on these conditions. Neprilysin inhibition with sacubitril/valsartan offers a new therapeutic strategy with a broad range of potential therapeutic actions. In PARADIGM-HF, the combination of neprilysin and RAAS inhibition was proven to be superior to enalapril for patients with stable NYHA class II-III heart failure and reduced left ventricular ejection fraction. Preliminary data suggests it may also have a role in other cardiovascular and non-cardiovascular disease. Several ongoing and planned studies will determine the extent of its benefit for these other indications.

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

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

The Accuracy of Portable Monitoring in Diagnosing Significant Sleep Disordered Breathing in Hospitalized Patients

BACKGROUND

Polysomnograms are not always feasible when sleep disordered breathing (SDB) is suspected in hospitalized patients. Portable monitoring is a practical alternative; however, it has not been recommended in patients with comorbidities.

OBJECTIVE

We evaluated the accuracy of portable monitoring in hospitalized patients suspected of having SDB.

DESIGN

Prospective observational study.

SETTING

Large, public, urban, teaching hospital in the United States.

PARTICIPANTS

Hospitalized patients suspected of having SDB.

METHODS

Patients underwent portable monitoring combined with actigraphy during the hospitalization and then polysomnography after discharge. We determined the accuracy of portable monitoring in predicting moderate to severe SDB and the agreement between the apnea hypopnea index measured by portable monitor (AHIPM) and by polysomnogram (AHIPSG).

RESULTS

Seventy-one symptomatic patients completed both tests. The median time between the two tests was 97 days (IQR 25-75: 24-109). Forty-five percent were hospitalized for cardiovascular disease. Mean age was 52±10 years, 41% were women, and the majority had symptoms of SDB. Based on AHIPSG, SDB was moderate in 9 patients and severe in 39. The area under the receiver operator characteristics curve for AHIPM was 0.8, and increased to 0.86 in patients without central sleep apnea; it was 0.88 in the 31 patients with hypercapnia. For predicting moderate to severe SDB, an AHIPM of 14 had a sensitivity of 90%, and an AHIPM of 36 had a specificity of 87%. The mean±SD difference between AHIPM and AHIPSG was 2±29 event/hr.

CONCLUSION

In hospitalized, symptomatic patients, portable monitoring is reasonably accurate in detecting moderate to severe SDB.

Is Mixed Apnea Associated with Non-Rapid Eye Movement Sleep a Reversible Compensatory Sign of Heart Failure?

Patient: Male, 24

Final Diagnosis: Dilated cardiomyopathy

Symptoms: Biventricular heart failure • sleep apnea

Medication: —

Clinical Procedure: Heart transplantation

Specialty: Cardiology

Sleep-disordered breathing and cardiovascular disease

Sleep-disordered breathing (SDB) is a common comorbidity in a number of cardiovascular diseases, and mounting clinical evidence demonstrates that it has important implications in the long-term outcomes of patients with cardiovascular disease (CVD). While recognition among clinicians of the role of SDB in CVD is increasing, it too often remains neglected in the routine care of patients with CVD, and therefore remains widely undiagnosed and untreated. In this article, we provide an overview of SDB and its relationship to CVD, with the goal of helping cardiovascular clinicians better recognize and treat this important comorbidity in their patients. We will describe the two major types of SDB and discuss the pathophysiologic, diagnostic, and therapeutic considerations of SDB in patients with CVD.

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.

Prevalence and Impact of Sleep Disordered Breathing in Patients with Severe Aortic Stenosis

BACKGROUND

Unlike the well-established association between sleep disordered breathing (SDB) and chronic heart failure, the relationship between SDB and severe aortic stenosis (AS) is not well investigated. Given the increasing prevalence of AS, and the improving prognosis of high risk AS patients attributable to transcatheter aortic valve implantation (TAVI), the prevalence and impact of SDB needs to be better understood.

METHODS AND RESULTS

In this study, 140 patients with severe AS underwent polygraphy prior to TAVI. Clinical and hemodynamic parameters were recorded. Patients were followed for 573±405 days. We found that 99/140 patients (71%) had SDB with a mean apnoea-hypopnoea-index of 24±17/h. SDB was mild in 27%, moderate in 23% and severe in 21% of patients. In addition, 35 patients (25%) had obstructive sleep apnoea (OSA), whereas 64 patients (46%) had central sleep apnoea (CSA). Patients with OSA had predominantly mild SDB (20/38 pts.), and patients with CSA mostly had severe SDB (24/29 pts.). The prevalence and distribution of OSA and CSA were independent of left ventricular function. Overall, 1 and 2 year survival rates (74% and 71%, resp.) did not differ significantly between patients without SDB or those with OSA and CSA (p=0.81).

CONCLUSIONS

SDB, with a preponderance of CSA, was found to be highly prevalent in patients with high-grade AS scheduled for TAVI. SDB prevalence was independent of left ventricular function. Mortality after TAVI was not influenced by the type or severity of SDB.

Clinical effectiveness and cost-effectiveness results from the randomised controlled Trial of Oral Mandibular Advancement Devices for Obstructive sleep apnoea-hypopnoea (TOMADO) and long-term economic analysis of oral devices and continuous positive airway pressure

BACKGROUND

Obstructive sleep apnoea-hypopnoea (OSAH) causes excessive daytime sleepiness (EDS), impairs quality of life (QoL) and increases cardiovascular disease and road traffic accident risks. Continuous positive airway pressure (CPAP) treatment is clinically effective but undermined by intolerance, and its cost-effectiveness is borderline in milder cases. Mandibular advancement devices (MADs) are another option, but evidence is lacking regarding their clinical effectiveness and cost-effectiveness in milder disease.

OBJECTIVES

(1) Conduct a randomised controlled trial (RCT) examining the clinical effectiveness and cost-effectiveness of MADs against no treatment in mild to moderate OSAH. (2) Update systematic reviews and an existing health economic decision model with data from the Trial of Oral Mandibular Advancement Devices for Obstructive sleep apnoea-hypopnoea (TOMADO) and newly published results to better inform long-term clinical effectiveness and cost-effectiveness of MADs and CPAP in mild to moderate OSAH.

TOMADO

A crossover RCT comparing clinical effectiveness and cost-effectiveness of three MADs: self-moulded [SleepPro 1™ (SP1); Meditas Ltd, Winchester, UK]; semibespoke [SleepPro 2™ (SP2); Meditas Ltd, Winchester, UK]; and fully bespoke [bespoke MAD (bMAD); NHS Oral-Maxillofacial Laboratory, Addenbrooke's Hospital, Cambridge, UK] against no treatment, in 90 adults with mild to moderate OSAH. All devices improved primary outcome [apnoea-hypopnoea index (AHI)] compared with no treatment: relative risk 0.74 [95% confidence interval (CI) 0.62 to 0.89] for SP1; relative risk 0.67 (95% CI 0.59 to 0.76) for SP2; and relative risk 0.64 (95% CI 0.55 to 0.76) for bMAD (p < 0.001). Differences between MADs were not significant. Sleepiness [as measured by the Epworth Sleepiness Scale (ESS)] was scored 1.51 [95% CI 0.73 to 2.29 (SP1)] to 2.37 [95% CI 1.53 to 3.22 (bMAD)] lower than no treatment (p < 0.001), with SP2 and bMAD significantly better than SP1. All MADs improved disease-specific QoL. Compliance was lower for SP1, which was unpopular at trial exit. At 4 weeks, all devices were cost-effective at £20,000/quality-adjusted life-year (QALY), with SP2 the best value below £39,800/QALY.

META-ANALYSIS

A MEDLINE, EMBASE and Science Citation Index search updating two existing systematic reviews (one from November 2006 and the other from June 2008) to August 2013 identified 77 RCTs in adult OSAH patients comparing MAD with conservative management (CM), MADs with CPAP or CPAP with CM. MADs and CPAP significantly improved AHI [MAD -9.3/hour (p < 0.001); CPAP -25.4/hour (p < 0.001)]. Effect difference between CPAP and MADs was 7.0/hour (p < 0.001), favouring CPAP. No trials compared CPAP with MADs in mild OSAH. MAD and CPAP reduced the ESS score similarly [MAD 1.6 (p < 0.001); CPAP 1.6 (p < 0.001)].

LONG-TERM COST-EFFECTIVENESS

An existing model assessed lifetime cost-utility of MAD and CPAP in mild to moderate OSAH, using the revised meta-analysis to update input values. The TOMADO provided utility estimates, mapping ESS score to European Quality of Life-5 Dimensions three-level version for device cost-utility. Using SP2 as the standard device, MADs produced higher mean costs and mean QALYs than CM [incremental cost-effectiveness ratio (ICER) £6687/QALY]. From a willingness to pay (WTP) of £15,367/QALY, CPAP is cost-effective, although the likelihood of MADs (p = 0.48) and CPAP (p = 0.49) being cost-effective is very similar. Both were better than CM, but there was much uncertainty in the choice between CPAP and MAD (at a WTP £20,000/QALY, the probability of being the most cost-effective was 47% for MAD and 52% for CPAP). When SP2 lifespan increased to 18 months, the ICER for CPAP compared with MAD became £44,066. The ICER for SP1 compared with CM was £1552, and for bMAD compared with CM the ICER was £13,836. The ICER for CPAP compared with SP1 was £89,182, but CPAP produced lower mean costs and higher mean QALYs than bMAD. Differential compliance rates for CPAP reduces cost-effectiveness so MADs become less costly and more clinically effective with CPAP compliance 90% of SP2.

CONCLUSIONS

Mandibular advancement devices are clinically effective and cost-effective in mild to moderate OSAH. A semi-bespoke MAD is the appropriate first choice in most patients in the short term. Future work should explore whether or not adjustable MADs give additional clinical and cost benefits. Further data on longer-term cardiovascular risk and its risk factors would reduce uncertainty in the health economic model and improve precision of effectiveness estimates.

TRIAL REGISTRATION

This trial is registered as ISRCTN02309506.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 18, No. 67. See the NIHR Journals Library website for further project information.

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

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

Leptin deficiency promotes central sleep apnea in patients with heart failure

BACKGROUND

Leptin-deficient animals hyperventilate. Leptin expression by adipocytes is attenuated by atrial natriuretic peptide (ANP). Increased circulating natriuretic peptides (NPs) are associated with an increased risk of central sleep apnea (CSA). This study tested whether serum leptin concentration is inversely correlated to NP concentration and decreased in patients with heart failure (HF) and CSA.

METHODS

Subjects with HF (N = 29) were studied by measuring leptin, NPs, CO2 chemosensitivity (Δminute ventilation [V.e]/Δpartial pressure of end-tidal CO2 [Petco2]), and ventilatory efficiency (V.e/CO2 output [V.co2]) and were classified as CSA or no sleep-disordered breathing by polysomnography. CSA was defined as a central apnea-hypopnea index ≥ 15. The Student t test, Mann-Whitney U test, and logistic regression were used for analysis, and data were summarized as mean ± SD; P &lt; .05 was considered significant.

RESULTS

Subjects with CSA had higher ANP and brain natriuretic peptide (BNP) concentrations (P &lt; .05), ΔV.e/ΔPetco2 (2.39 ± 1.03 L/min/mm Hg vs 1.54 ± 0.35 L/min/mm Hg, P = .01), and V.e/V.co2 (43 ± 9 vs 34 ± 7, P &lt; .01) and lower leptin concentrations (8 ± 10.7 ng/mL vs 17.1 ± 8.8 ng/mL, P &lt; .01). Logistic regression analysis (adjusted for age, sex, and BMI) demonstrated leptin (OR = 0.07; 95% CI, 0.01-0.71; P = .04) and BNP (OR = 4.45; 95% CI, 1.1-17.9; P = .05) to be independently associated with CSA.

CONCLUSIONS

In patients with HF and CSA, leptin concentration is low and is inversely related to NP concentration. Counterregulatory interactions of leptin and NP may be important in ventilatory control in HF.

Sleep-disordered breathing in heart failure: identifying and treating an important but often unrecognized comorbidity in heart failure patients

Sleep-disordered breathing (SDB) is the most common comorbidity in patients with heart failure (HF) and has a significant impact on quality of life, morbidity, and mortality. A number of therapeutic options have become available in recent years that can improve quality of life and potentially the outcomes of HF patients with SDB. Unfortunately, SDB is not part of the routine evaluation and management of HF, so it remains untreated in most HF patients. Although recognition of the role of SDB in HF is increasing, clinical guidelines for the management of SDB in HF patients continue to be absent. This article provides an overview of SDB in HF and proposes a clinical care pathway to help clinicians to better recognize and treat SDB in their HF patients.

Association between sleep apnea and overnight hemodynamic changes in hospitalized heart failure patients with and without paroxysmal nocturnal dyspnea

BACKGROUND

Paroxysmal nocturnal dyspnea (PND) is a common symptom for patients with acute decompensated heart failure (ADHF). Some symptoms of PND are similar to those of sleep apnea (SA) which might be associated with overnight worsening hemodynamics in failing hearts. However, the association between PND, SA, and overnight change in hemodynamics in patients with heart failure remains uncertain.

METHODS

We studied 28 consecutive patients with reduced ejection fraction who were hospitalized with ADHF. Plasma atrial natriuretic peptide (ANP) levels were measured before and after overnight sleep study. PND was defined as having an episode of PND prior to hospitalization for ADHF.

RESULTS

Ten (36%) patients had a history of PND. Respiratory disturbance index (the frequency and severity of sleep apnea) was an independent factor associated with a history of PND (odds ratio 1.24, 95% confidence interval 1.05-1.47, p=0.011). In those without PND, plasma ANP levels decreased from before sleep to after waking, whereas in those with PND it increased (p=0.011). In addition, overnight change in plasma ANP levels was independently associated with respiratory disturbance index (p=0.035).

CONCLUSION

These results thus suggest that in patients with ADHF, SA might be a predisposing cause of PND in association with overnight worsening hemodynamics.