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

Central sleep apnea: emphasizing recognition and differentiation

INTRODUCTION

Central sleep apnea (CSA) is a sleep-related breathing disorder in which the effort to breathe is intermittently diminished or absent. CSA is a common disorder among patients with different cardiovascular disorders, including heart failure. In addition, a growing number of medications have been shown to induce CSA and CSA can emerge after initiation of treatment for obstructive sleep apnea. Accumulating evidence shows that CSA is a heterogeneous disorder with individual differences in clinical and biological characteristics and/or underlying pathophysiological mechanisms.

AREAS COVERED

This narrative review offers an overview of the diagnostic aspects and classification of CSA, with an emphasis on heart failure patients, patients with CSA due to a medication and treatment-emergent CSA. The importance of evaluation of prognostic biomarkers in patients with different types of CSA is discussed. This narrative review synthesizes literature on CSA sourced from the PubMed database up to February 2024.

EXPERT OPINION

CSA presents a remarkably diverse disorder, with treatment modalities exhibiting potentially varied efficacy across its various phenotypes. This highlights the imperative for tailored management strategies that are rooted in phenotype classification.

Effects of Adaptive Servo-Ventilation on Quality of Life: The READ-ASV Registry

Rationale: Adaptive servo-ventilation (ASV) effectively treats sleep-disordered breathing, including central sleep apnea (CSA) and coexisting obstructive sleep apnea (OSA).Objectives: The prospective, multicenter European READ-ASV (Registry on the Treatment of Central and Complex Sleep-Disordered Breathing with Adaptive Servo-Ventilation) registry investigated the effects of first-time ASV therapy on disease-specific quality of life (QoL).Methods: The registry enrolled adults with CSA with or without OSA who had ASV therapy prescribed between September 2017 and March 2021. The primary endpoint was change in disease-specific QoL (Functional Outcomes of Sleep Questionnaire [FOSQ]) score between baseline and 12-month follow-up. Sleepiness determined using the Epworth Sleepiness Scale (ESS) score was a key secondary outcome. For subgroup analysis, participants were classified as symptomatic (FOSQ score < 17.9 and/or ESS score > 10) or asymptomatic (FOSQ score ⩾ 17.9 and/or ESS score ⩽ 10).Results: A total of 801 individuals (age, 67 ± 12 yr; 14% female; body mass index, 31 ± 5 kg/m2; apnea-hypopnea index, 48 ± 22/h) were enrolled; analyses include those with paired baseline and follow-up data. After 12 ± 3 months on ASV, median (interquartile range) FOSQ score had increased significantly from baseline (+0.8 [-0.2 to 2.2]; P < 0.001; n = 499). This was due to a significantly increased FOSQ score in symptomatic participants (+1.69 [0.38 to 3.05]), with little change in asymptomatic individuals (+0.11 [-0.39 to 0.54]). The median ESS score also improved significantly from baseline during ASV (-2.0 [-5.0 to 0.0]; P < 0.001).Conclusions: ASV treatment of CSA with or without coexisting OSA was associated with improvements in disease-specific QoL and daytime sleepiness, especially in individuals with sleep-disordered breathing symptoms before therapy initiation. These improvements in patient-reported outcomes support the use of ASV in this population.

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

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

[Objective sleep characteristics and risk factors for sleep apnea in heart failure patients with different left ventricular ejection fraction]

OBJECTIVE

To investigate the objective sleep characteristics and the independent risk factors for sleep apnea in heart failure (HF) patients with different left ventricular ejection fractions (LVEF).

METHODS

A total of 107 patients with chronic HF hospitalized in the Department of Cardiology of our hospital from April, 2019 to October, 2020 were included in this study. According to the LVEF measured by echocardiography, the patients were divided into reduced ejection fraction (HFrEF) group (n=35), mid-range ejection fraction (HFmrEF) group (n=21), and preserved ejection fraction (HFpEF) group (n=51). The baseline demographic and clinical characteristics of the patients were recorded. To assess the objective sleep characteristics, whole night polysomnography was scheduled for all the patients. Spearman correlation and multinomial logistic regression analyses were used to explore the factors affecting objective sleep characteristics.

RESULTS

The patients in HFpEF group had significantly lower proportion of non-rapid eye movement sleep stage 1, apnea hypopnea index (AHI), and central sleep apnea (CSA) than those in HFrEF group (all P < 0.05). The baseline demographic data or sleep structures in HFmrEF group did not differ significantly from those in the other two groups. Spearman correlation analysis revealed significant correlations of the male sex, diuretics use, NT-proBNP, LVEF, and total cholesterol levels with the severity of AHI (all P < 0.05). After adjusting for potential confounders, multiple logistics regression analysis showed that age, drinking, and LVEF levels were independently associated with the severity of AHI (all P < 0.05).

CONCLUSION

Abnormal objective sleep architectures occur in all HF patients, manifested mainly by sleep apnea. The incidences of sleep apnea and CSA are lower in patients with HFpEF than in those with HFrEF. Age, drinking, and LVEF levels are independent risk factors for the occurrence and severity of sleep apnea.