Cheyne-Stokes Respiration in Patients with Heart Failure

Changes in cognitive function and daytime sleepiness in patients with chronic heart failure and Cheyne-Stokes respiration with adaptive servo ventilation treatment

STUDY OBJECTIVES

Cheyne - Stokes respiration (CSR) is prevalent in patients with chronic heart failure (CHF). Adaptive Servo Ventilation (ASV) alleviates CSR and improves objective sleep quality. We investigated the effects of ASV on neurocognitive function in the symptomatic phenotype of patients with CSR and CHF.

METHODS

This case series included patients diagnosed with stable CHF (NYHA ≥ II) and CSR (N = 8). Sleep and neurocognitive function were assessed at baseline and after 1- and 6-months following initiation of ASV treatment.

RESULTS

In CHF patients (n = 8, median age 78.0[64.5-80.8] years and BMI 30.0[27.0-31.5] kg/m2, median ejection fraction 30[24-45]%, Epworth Sleepiness Scale (ESS) score 11.5[9.0-15.0]), ASV markedly improved respiration during sleep (Apnea-Hypopnea Index (AHI) 44.1[39.0-51.5]n/h at baseline, 6.3[2.4-9.7]n/h at 6 months treatment, respectively, p < 0.01). The 6-min-walk test distance increased by treatment from (295.0[178.8-385.0] m to 356.0[203.8-495.0] m (p = 0.05)). Sleep structure was modified, and Stage 3 increased markedly from 6.4[1.7-20.1] % to 20.8[14.2-25.3] %, p < 0.02). Sleep latency in the Maintenance of Wakefulness Test increased from 12.0[6.0-30.0] min to 26.3[12.0-30.0] min, (p = 0.04). In the Attention Network Test, evaluating neurocognition, the number of lapses decreased from 6.0[1.0-44.0] to 2.0[0.3-8.0], (p = 0.05) and the overall number of responses to a preset stimulus increased after treatment (p = 0.04).

CONCLUSIONS

ASV treatment in CHF patients with CSR may improve sleep quality, neurocognition and daytime performance.

Breathing rate variability in obstructive sleep apnea during wakefulness

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) is defined by pauses in breathing during sleep, but daytime breathing dysregulation may also be present. Sleep may unmask breathing instability in OSA that is usually masked by behavioral influences during wakefulness. A breath-hold (BH) challenge has been used to demonstrate breathing instability. One measure of breathing stability is breathing rate variability (BRV). We aimed to assess BRV during rest and in response to BH in OSA.

METHODS

We studied 62 participants (31 with untreated OSA: respiratory event index [mean ± SD] 20 ± 15 events/h, 12 females, age 51 ± 14 years, body mass index [BMI] 32 ± 8 kg/m²; 31 controls: 17 females, age 47 ± 13 years; BMI 26 ± 4 kg/m²). Breathing movements were collected using a chest belt for 5 minutes of rest and during a BH protocol (60 seconds baseline, 30 seconds BH, 90 seconds recovery, 3 repeats). From the breathing movements, we calculated median breathing rate (BR) and interquartile BRV at rest. We calculated change in BRV during BH recovery from baseline. Group comparisons of OSA vs control were conducted using analysis of covariance with age, sex, and BMI as covariates.

RESULTS

We found 10% higher BRV in OSA vs controls (P < .05) during rest. In response to BH, BRV increased 7% in OSA vs 1% in controls (P < .001). Resting BR was not significantly different in OSA and controls, and sex and age did not have any significant interaction effects. BMI was associated with BR at rest (P < .05) and change in BRV with BH (P < .001), but no significant BMI-by-group interaction effect was observed.

CONCLUSIONS

The findings suggest breathing instability as reflected by BRV is high in OSA during wakefulness, both at rest and in response to a stimulus. Breathing instability together with high blood pressure variability in OSA may reflect a compromised cardiorespiratory consequence in OSA during wakefulness.

CITATION

Pal A, Martinez F, Akey MA, et al. Breathing rate variability in obstructive sleep apnea during wakefulness. J Clin Sleep Med. 2022;18(3):825-833.

The success rate of split-night polysomnography and its impact on continuous positive airway pressure compliance

OBJECTIVES:

With the increased volume of referrals of patients with obstructive sleep apnea (OSA) for sleep studies, there is a great need for alternatives of the standard two-night polysomnography (PSG) like split-night PSG. Therefore, we conducted this study to determine the success rate of continuous positive airway pressure (CPAP) titration during split-night PSG, and to determine the predictors of titration success and the impact on subsequent CPAP compliance in Saudi patients with OSA.

METHODS:

This is a prospective cohort study that included consecutive patients who were diagnosed with OSA and underwent a split-night PSG (n = 454). A subgroup of patients who used CPAP therapy, agreed to come for follow-up after 4 and 10 months (n = 130). This subgroup was compared with a matched group of OSA patients who underwent a two-night sleep study protocol (n = 80).

RESULTS:

The study group had a mean age of 48.7 ± 13.3 years, body mass index (BMI) of 37.5 ± 10.1 kg/m² and apnea hypopnea index of 58.4 ± 35.0 events/h. Successful CPAP titration was achieved in 350 (77%) patients. In a full adjusted model, “BMI >35 kg/m²” and “known cardiac disease” remained significant predictors of a lower success rate of CPAP titration. After 10 months, 88% of the patients in the split-night protocol met the set criteria for good compliance versus 85% in the two-night protocol.

CONCLUSION:

Split-night protocol is an effective protocol for diagnosing OSA and titrating CPAP. CPAP compliance rate showed no difference between the split-night and the two-night protocols.

Periodic Breathing in Heart Failure Explained by Dynamic and Static Properties of Respiratory Control

OBJECTIVE

The respiratory operating point is determined by the interplay between the controller and plant subsystem elements within the respiratory chemoreflex feedback system. This study aimed to establish the methodological basis for quantitative analysis of the open-loop dynamic properties of the human respiratory control system and to apply the results to explore detailed mechanisms of the regulation of respiration and the possible mechanism of periodic breathing in chronic heart failure.

METHODS AND RESULTS

In healthy volunteers, we measured arterial CO₂ partial pressure (Pa_CO2) and minute ventilation (V˙E) to estimate the dynamic properties of the controller ( PaCO2→V˙E relation) and plant ( V˙E→PaCO2 relation). The dynamic properties of the controller and plant approximated first- and second-order exponential models, respectively, and were described using parameters including gain, time constant, and lag time. We then used the open-loop transfer functions to simulate the closed-loop respiratory response to an exogenous disturbance, while manipulating the parameter values to deviate from normal values but within physiological ranges. By increasing both the product of gains of the two subsystem elements (total loop gain) and the lag time, the condition of system oscillation (onset of periodic breathing) was satisfied.

CONCLUSION

When abnormality occurs in a part of the respiratory chemoreflex system, instability of the control system is amplified and may result in the manifestation of respiratory abnormalities such as periodic breathing.

Adaptive servoventilation improves cardiac dysfunction and prognosis in heart failure patients with sleep-disordered breathing: a meta-analysis

BACKGROUND

Adaptive servoventilation (ASV) is a new therapeutic modality to treat sleep-disordered breathing (SDB) especially for central sleep apnoea associated with Cheyne-Stokes respiration, whereas the role of ASV in SDB patients with heart failure (HF) is controversial. The purpose of this study was to evaluate the effects of ASV on these patients through a meta-analysis of published data.

METHODS

A comprehensive literature search was performed to identify studies focused on ASV through databases, including PubMed, Medline, Embase, Cochrane Library and Web of science from 1950 to 2014. Parallel randomised controlled trials which compared ASV to other controls in HF and SDB patients with extractable data were meet our inclusion criteria. Random effects meta-analysis models were applied using RevMan 5.2.

RESULTS

Seven studies involving 301 patients were recruited in the meta-analysis. The weighted mean difference in apnoea hyponea index (-17.73 events/h, 95% CI, -21.85 to -2.94) and left ventricular ejection fraction (MD: 4.68, 95% CI, 2.74-6.63) both favored ASV compared to control conditions. The urinary noradrenaline level (MD: -32.18, 95%CI: -44.07 to -20.09) was decreased, while the exercise capacity measured by 6-min walk distance (MD: 41.26, 95% CI, 17.06-65.45) was improved after ASV treatment. Whereas neither left ventricular end-diastolic diameter (LVEDD) nor Epworth sleepiness-scale score (ESS) significantly changed after ASV therapy.

CONCLUSIONS

ASV is superior to other therapy, as it can result in good consequences for patients with SDB and improve their prognosis in cardiac function. Further studies will still be needed to assess the benefit of it.

Cheyne-Stokes respiration during sleep: mechanisms and potential interventions

Cheyne-Stokes respiration is characterized by a typical waxing and waning pattern in breathing amplitude, interspersed with central apnoeas or hypopnoeas. This article reviews current knowledge regarding Cheyne-Stokes respiration with a particular emphasis on the mechanisms and latest methods of intervention.

Compensation: a contemporary regulatory machinery in cardiovascular diseases?

Both clinical and experimental findings at the molecular, cellular, tissue, organ and systematic levels have depicted the presence of a contemporary regulatory machinery namely compensation in various forms of cardiovascular diseases. Compensation is believed to be present and regulated within the scope of a biological entity and represents the initiation of dyshomeostasis. Compensation can be identified in multiple categories and organs in cardiovascular diseases at multiple levels. The capacity to reduce the unfavorable pathological compensation may be a criterion to evaluate the therapeutic effectiveness for cardiovascular diseases. This mini-review tries to take compensation into consideration in the understanding of onset and progression of cardiovascular diseases in particular, and thus, better or optimal therapeutic approaches may be achieved for the prevention and management of cardiovascular diseases.

Brainstem involvement as a cause of central sleep apnea: pattern of microstructural cerebral damage in patients with cerebral microangiopathy

Background

The exact underlying pathomechanism of central sleep apnea with Cheyne-Stokes respiration (CSA-CSR) is still unclear. Recent studies have demonstrated an association between cerebral white matter changes and CSA. A dysfunction of central respiratory control centers in the brainstem was suggested by some authors. Novel MR-imaging analysis tools now allow far more subtle assessment of microstructural cerebral changes. The aim of this study was to investigate whether and what severity of subtle structural cerebral changes could lead to CSA-CSR, and whether there is a specific pattern of neurodegenerative changes that cause CSR. Therefore, we examined patients with Fabry disease (FD), an inherited, lysosomal storage disease. White matter lesions are early and frequent findings in FD. Thus, FD can serve as a "model disease" of cerebral microangiopathy to study in more detail the impact of cerebral lesions on central sleep apnea.

Patients and Methods

Genetically proven FD patients (n = 23) and age-matched healthy controls (n = 44) underwent a cardio-respiratory polysomnography and brain MRI at 3.0 Tesla. We applied different MR-imaging techniques, ranging from semiquantitative measurement of white matter lesion (WML) volumes and automated calculation of brain tissue volumes to VBM of gray matter and voxel-based diffusion tensor imaging (DTI) analysis.

Results

In 5 of 23 Fabry patients (22%) CSA-CSR was detected. Voxel-based DTI analysis revealed widespread structural changes in FD patients when compared to the healthy controls. When calculated as a separate group, DTI changes of CSA-CSR patients were most prominent in the brainstem. Voxel-based regression analysis revealed a significant association between CSR severity and microstructural DTI changes within the brainstem.

Conclusion

Subtle microstructural changes in the brainstem might be a neuroanatomical correlate of CSA-CSR in patients at risk of WML. DTI is more sensitive and specific than conventional structural MRI and other advanced MR analyses tools in demonstrating these abnormalities.

Cheyne-Stokes respiration due to chronic heart failure abates with coronary artery revascularization

A 78-year-old man presented with dyspnea and mild heart failure with Cheyne-Stokes respiration (CSR). Workup revealed inferolateral ischemia in the setting of significant triple vessel coronary disease, and nil else to adequately explain his dyspnea and eventual respiratory failure. After he underwent surgical revascularization, his ventricular function improved, leading to resolution of his respiratory failure and, of interest, his CSR. CSR is a central sleep apnea common in heart failure patients and has been associated with increased mortality. Here, we present the first English-literature report of CSR abating with surgical coronary revascularization, and briefly review the literature.

Analysis of the respiratory flow cycle morphology in chronic heart failure patients applying principal components analysis

The study of flow cycle morphology provides new information about the breathing pattern. This study proposes the characterization of cycle morphology in chronic heart failure patients (CHF) patients, with periodic (PB) and non-periodic breathing (nPB) patterns, and healthy subjects. Principal component analysis is applied to extract a respiratory cycle model for each time segment defined by a 30-s moving window. To characterize morphology of the model waveform, a number of parameters are extracted whose significance is evaluated in terms of the following three classification problems: CHF patients with either PB or nPB, CHF patients versus healthy subjects, and nPB patients versus healthy subjects. 26 CHF patients (8 with PB and 18 with non-periodic breathing pattern (nPB)) and 35 healthy subjects are studied. The results show that a respiratory cycle compressed in time characterizes PB patients, i.e., shorter inspiratory and expiratory periods, and higher dispersion of the maximum inspiratory and expiratory flow value (accuracy of 87%). The maximal expiratory flow instant occurs earlier in CHF patients than in healthy subjects (accuracy of 87%), with a steeper slope between inspiration and expiration. It is also found that the standard deviation of the expiratory period, evaluated for each subject, is much lower in CHF patients than in healthy subjects. The maximal expiratory flow instant occurs earlier (accuracy of 84%) in nPB patients, when comparing subjects with similar respiratory pattern like nPB patients and healthy subjects.

Comparison of acute and chronic impact of adaptive servo-ventilation on left chamber geometry and function in patients with chronic heart failure

AIMS

The aim of this study was to determine differences in the acute and chronic impact of adaptive servo-ventilation (ASV) on left chamber geometry and function in patients with chronic heart failure (CHF).

METHODS AND RESULTS

An acute ASV study was performed to measure echocardiographic parameters before and 30 min after the initiation of ASV therapy in 30 CHF patients (mean age: 69 years, 23 male). The chronic effects of ASV therapy were also evaluated in 26 of these 30 patients over a mean follow-up period of 24 weeks. Patients were divided into two groups according to the status of ASV therapy [ASV group (n= 15) and withdrawal group (n= 11)]. In the acute study, heart rate and blood pressure were significantly decreased 30 min after the ASV therapy compared with baseline. Stroke volume and cardiac output were significantly increased in conjunction with a reduction in systemic vascular resistance. Multivariate regression analysis revealed baseline E/e' to be an independent predictor for absolute increase in cardiac output. In the chronic study, a significant reduction of left ventricular (LV)/left atrial (LA) volumes and the severity of mitral regurgitation (MR), and improved LV diastolic function parameters were noted in the ASV group. These beneficial effects were not observed in the withdrawal group.

CONCLUSION

The acute beneficial impact of ASV is mainly associated with the reduction of afterload resulting in an increase in stroke volume and cardiac output. In contrast, chronic ASV therapy produces LV and LA reverse remodelling resulting in an improvement in LV function and the severity of MR in patients with CHF.

Correlations of physiological activities in nocturnal Cheyne-Stokes respiration

We have conducted a power-spectrum-density (PSD) analysis of the distinct sleep stages of a previously diagnosed nocturnal Cheyne-Stokes respiration patient (NCSR) and studied the correlations of different physiological activities. This is the first study where the correlations were analyzed separately for different sleep stages and the influence of arousals was completely eliminated. Mathematical analysis of the polysomnographical records revealed clear indicators of the disorder in the form of large peaks in a very-low frequency range of f ≈ 0.02 Hz. We have shown existence of the significant entrainment of the cerebral and cardiac activities with respiration during different stages of sleep in the patient. The entrainment is highly pronounced in light (stage 2) and deep (stage 3) sleep, but is significantly less pronounced in rapid eye movement sleep. A correlation functions analysis revealed that the correlations between the central activities and respiration attain maximum at negative lag times. Lagging of respiration behind the central activities favors the central hypothesis of generation of NCSR. On the basis of comparison of PSD plots of a NCSR patient and a healthy patient we speculate that the vasomotor center of a NCSR patient assumes the control function in the respiratory control system. Clinical applications of the findings of the study may lead to the development of novel low-cost methods of diagnostic of NCSR based on easy-to-obtain electrocardiogram or electroencephalogram records of patients and emergence of some forms of "substitution therapy".