Cycle length identifies obstructive sleep apnea and central sleep apnea in heart failure with reduced ejection fraction

Aim

To clarify whether unmasking of central sleep apnea during continuous positive airway pressure (CPAP) initiation can be identified from initial diagnostic polysomnography (PSG) in patients with heart failure with reduced ejection fraction (HFREF) and obstructive sleep apnea (OSA)

Materials and methods

Forty-three consecutive patients with obstructive sleep apnea and central sleep apnea (OSA/CSA) in HFREF were matched with 43 HFREF patients with OSA and successful CPAP initiation. Obstructive apneas during diagnostic PSG were then analyzed for cycle length (CL), ventilation length (VL), apnea length (AL), time to peak ventilation (TTPV), and circulatory delay (CD). We calculated duty ratio (DR) as the ratio of VL/CL and mathematic loop gain (LG).

Results

While AL was similar, CL, VL, TTPV, CD, and DR was significantly longer in patients with OSA/CSA compared to those with OSA, and LG was significantly higher. Receiver operator curves identified optimal cutoff values of 50.2 s for CL (area under the curve (AUC) 0.85, 29.2 s for VL (AUC 0.92), 11.5 s for TTPV (AUC 0.82), 26.4 s for CD (AUC 0.79), and 3.96 (AUC 0.78)) respectively for LG to identify OSA/CSA.

Conclusion

OSA/CSA in HFREF can be identified by longer CL, VL, TTPV, and CD from obstructive events in initial diagnostic PSG. The underlying mechanisms seem to be the presence of an increased LG.

     

Sleepiness and sleep in patients with both systolic heart failure and obstructive sleep apnea

BACKGROUND: Adverse effects of obstructive sleep apnea (OSA), including sleep deprivation, can contribute to the progression of heart failure. The usual indication to diagnose and treat sleep apnea is subjective sleepiness. Previous studies suggest that patients with both heart failure and obstructive sleep apnea often do not complain of sleepiness, albeit their sleep time may be reduced. Therefore, we tested the hypothesis that patients with heart failure have less sleepiness and sleep less compared with subjects without heart failure for a given severity of OSA. METHODS: Sleepiness assessed with the Epworth Sleepiness Scale and sleep structure measured with polysomnography were compared among 155 consecutive patients with heart failure and from a random community sample (n = 1139) according to categories of the apnea-hypopnea index (<5, no OSA; 5-14, mild OSA; and > or =15, moderate to severe OSA). RESULTS: Compared with the community sample, for any given severity of OSA, patients with heart failure had lower mean +/- SE Epworth Sleepiness Scale scores (7.1 +/- 0.4 vs 8.3 +/- 0.2 [P = .005]; 6.7 +/- 0.7 vs 9.2 +/- 0.3 [P < .001]; and 7.8 +/- 0.7 vs 9.8 +/- 0.4 [P = .01]), indicating less sleepiness despite sleeping less (total sleep time mean +/- SE [in minutes]: 306 +/- 7 vs 384 +/- 2, 295 +/- 19 vs 384 +/- 5, and 285 +/- 13 vs 359 +/- 7 for no, mild, and moderate to severe OSA, respectively; P < .001 for all comparisons). CONCLUSIONS: Patients with heart failure have less subjective daytime sleepiness compared with individuals from a community sample, despite significantly reduced sleep time, whether or not they have OSA. In patients with heart failure, the absence of subjective sleepiness is not a reliable means of ruling out OSA.     

Periodicity of obstructive sleep apnea in patients with and without heart failure

STUDY OBJECTIVE: To determine whether the duration of the apnea-hyperpnea cycle is longer in patients with congestive heart failure (CHF) and obstructive sleep apnea (OSA) than in patients with OSA alone, and whether this is related to prolonged circulation time. DESIGN: Retrospective study. SETTING: Sleep laboratory of a university teaching hospital.Patients and intervention: Male patients with OSA and CHF (n = 22) or without CHF (n = 18) underwent overnight polysomnography. MEASUREMENTS AND RESULTS: Hyperpnea duration, time to peak tidal volume (Vt), and lung-to-ear circulation time (LECT) were measured in all patients. Compared to the non-CHF patients, those with CHF had significantly longer hyperpneas (25.7 +/- 7.8 s vs 17.6 +/- 5.6 s, p < 0.001) and LECT (14.9 +/- 3.4 s vs 9.0 +/- 1.8 s, p < 0.001) [mean +/- SD]. There was also a significant relationship between LECT and hyperpnea duration (r = 0.67, p < 0.001). CONCLUSION: In patients with CHF, prolonged lung-to-chemoreceptor circulation time influences the cycling characteristics of OSA such that it prolongs hyperpnea and sculpts a pattern resembling Cheyne-Stokes respiration. These findings further suggest that the increased tendency to periodic breathing in CHF may predispose to, or alter the physiologic manifestations of OSA.     

Relationship of systolic BP to obstructive sleep apnea in patients with heart failure

STUDY OBJECTIVES: Obstructive sleep apnea (OSA) is an independent risk factor for hypertension in the general population. Hypertension is, in turn, an important risk factor for the development and progression of congestive heart failure (CHF). Our objective was to determine whether OSA would be associated with elevated daytime BP in medically treated patients with CHF. DESIGN: Cross-sectional study. SETTING: Tertiary care, university-affiliated sleep disorders and heart failure clinics. PATIENTS: Three hundred one consecutive patients with CHF. MEASUREMENTS AND RESULTS: We measured daytime BP and performed overnight sleep studies to assess for the presence of OSA. Among these patients, OSA was present in 121 patients (40%) and their systolic BP was significantly higher than in patients without OSA. Patients with OSA were 2.89 times (95% confidence interval, 1.25 to 6.73) more likely to have systolic hypertension (ie, BP > or = 140 mm Hg) than those without OSA after controlling for other risk factors, including obesity. The degree of systolic BP elevation was directly related to the frequency of obstructive apneas and hypopneas. CONCLUSIONS: In medically treated patients with CHF, daytime systolic BP and the prevalence of systolic hypertension are significantly increased in patients with OSA, compared to those without OSA, independent of other potentially confounding factors. OSA may therefore have contributed to the presence of systolic hypertension in some of these patients.     

Influence of obstructive sleep apnea on mortality in patients with heart failure.

OBJECTIVES: This study sought to determine, in patients with heart failure (HF), whether untreated moderate to severe obstructive sleep apnea (OSA) is associated with a higher mortality rate than in patients with mild to no sleep apnea (M-NSA). BACKGROUND: Obstructive sleep apnea is common in patients with HF and exposes the heart and circulation to adverse mechanical and autonomic effects. However, its effect on mortality rates of patients with HF has not been reported. METHODS: In a prospective study involving 164 HF patients with left ventricular ejection fractions (LVEFs) < or =45%, we performed polysomnography and compared death rates between those with M-NSA (apnea-hypopnea index [AHI] <15/h of sleep) and those with untreated OSA (AHI > or =15/h of sleep). RESULTS: During a mean (+/- SD) of 2.9 +/- 2.2 and a maximum of 7.3 years of follow-up, the death rate was significantly greater in the 37 untreated OSA patients than in the 113 M-NSA patients after controlling for confounding factors (8.7 vs. 4.2 deaths per 100 patient-years, p = 0.029). Although there were no deaths among the 14 patients whose OSA was treated by continuous positive airway pressure (CPAP), the mortality rate was not significantly different from the untreated OSA patients (p = 0.070). CONCLUSIONS: In patients with HF, untreated OSA is associated with an increased risk of death independently of confounding factors.     

Severe obstructive sleep apnea is associated with left ventricular diastolic dysfunction

INTRODUCTION: Hypertension is common in patients with obstructive sleep apnea (OSA). However, the effect of OSA on ventricular function, especially diastolic function, is not clear. Therefore, we have assessed the prevalence of diastolic dysfunction in patients with OSA and the relationship between diastolic parameters and severity of OSA. METHODS: Sixty-eight consecutive patients with OSA confirmed by polysomnography underwent echocardiography. Diastolic function of the left ventricle was determined by transmitral valve pulse-wave Doppler echocardiography. Various baseline characteristics, severity of OSA, and echocardiographic parameters were compared between patients with and without diastolic dysfunction. RESULTS: There were 61 male and 7 female patients with a mean age of 48.1 +/- 11.1 years, body mass index of 28.5 +/- 4.3 kg/m(2), and apnea/hypopnea index (AHI) of 44.3 +/- 23.2/h (mean +/- SD). An abnormal relaxation pattern (ARP) in diastole was noted in 25 patients (36.8%). Older age (52.7 +/- 8.9 years vs 45.1 +/- 11.3 years, p = 0.005), hypertension (56% vs 20%, p = 0.002), and a lower minimum pulse oximetric saturation (SpO(2)) during sleep (70.5 +/- 17.9% vs 78.8 +/- 12.9%, respectively; p = 0.049) were more common in patients with ARP. By multivariate analysis, minimum SpO(2) < 70% was an independent predictor of ARP (odds ratio, 4.34; 95% confidence interval, 1.23 to 15.25; p = 0.02) irrespective of age and hypertension. Patients with AHI > or = 40/h had significantly longer isovolumic relaxation times than those with AHI < 40/h (106 +/- 19 ms vs 93 +/- 17 ms, respectively; p = 0.005). CONCLUSION: Diastolic dysfunction with ARP was common in patients with OSA. More severe sleep apnea was associated with a higher degree of left ventricular diastolic dysfunction in this study.     

Prospective study of obstructive sleep apnea and incident coronary heart disease and heart failure

Background-Clinic-based observational studies in men have reported that obstructive sleep apnea is associated with an increased incidence of coronary heart disease.The objective of this study was to assess the relation of obstructive sleep apnea to incident coronary heart disease and heart failure in a general community sample of adult men and women.Methods and Results-A total of 1927 men and 2495 women ≥40 years of age and free of coronary heart disease and heart failure at the time of baseline polysomnography were followed up for a median of 8.7 years in this prospective longitudinal epidemiological study.After adjustment for multiple risk factors,obstructive sleep apnea was a significant predictor of incident coronary heart disease(myocardial infarction,revascularization procedure,or coronary heart disease death)only in men ≤70 years of age(adjusted hazard ratio 1.10 [95% confidence interval 1.00 to 1.21] per 10-unit increase in apnea-hypopnea index [AHI])but not in older men or in women of any age.Among men 40 to 70 years old,those with AHI ≥30 were 68% more likely to develop coronary heart disease than those with AHI <5.Obstructive sleep apnea predicted incident heart failure in men but not in women(adjusted hazard ratio 1.13 [95% confidence interval 1.02 to 1.26] per 10-unit increase in AHI).Men with AHI ≥30 were 58% more likely to develop heart failure than those with AHI <5.Conclusions-Obstructive sleep apnea is associated with an increased risk of incident heart failure in community-dwelling middle-aged and older men;its association with incident coronary heart disease in this sample is equivocal.     

Central sleep apnea in patients with congestive heart failure

Central apnea during sleep represents a manifestation of breathing instability in many clinical conditions of varied etiologies. Central apnea is the result of transient cessation of ventilatory motor output, which represents that inhibitory influences favoring instability predominate over excitatory influence favoring stable breathing. This article will review the determinants of central apnea, the specific features of CHF-related central apnea, and outline a management approach     

Treatment of sleep apnea in heart failure

Obstructive and central sleep apnea are common in heart failure, and may participate in its progression by exposing the heart to intermittent hypoxia, increased preload and afterload, sympathetic activation, and vascular endothelial dysfunction. Treatment of sleep apnea in patients with heart failure may reverse these detrimental effects, in addition to alleviating symptoms of sleep apnea. In patients with heart failure and obstructive sleep apnea, short-term randomized trials have demonstrated that continuous positive airway pressure (CPAP) improves cardiac function, and lowers sympathetic activity and blood pressure. However, there are no data on whether treating obstructive sleep apnea in patients with heart failure improves morbidity and mortality. Various treatments have been tested in heart failure patients with central sleep apnea, particularly oxygen and CPAP. Both reduce the frequency of central respiratory events, and lower sympathetic activity. In addition, CPAP improves cardiac function. However, the largest randomized trial did not demonstrate any beneficial effect of CPAP on the rate of mortality and cardiac transplantation (32 vs. 32 events in the control and treatment groups, respectively; p=0.54), but ultimately lacked power to conclude with certainty whether CPAP has an effect on morbidity and mortality in such patients. Thus, although there are data to indicate that treating both obstructive and central sleep apnea in patients with heart failure improves cardiovascular function, larger randomized trials involving interventions such as oxygen, CPAP, or other forms of positive airway pressure will be required to determine whether treating these sleep-related breathing disorders reduces clinically important outcomes such as morbidity and mortality.     

Obstructive sleep apnea and heart failure

Obstructive sleep apnea (OSA) exerts several effects that may be particularly deleterious in patients with heart failure (HF). OSA should be considered especially in HF patients who are obese or have the metabolic syndrome, systemic hypertension, or pulmonary hypertension. HF patients in whom OSA is suspected should undergo a full evaluation by a sleep specialist, including a polysomnogram, to diagnose OSA and differentiate this disease from central sleep apnea. Those found to have OSA should then receive continuous positive airway pressure and/or other interventions, and standard disease management strategies should be used to maximize compliance. Those who cannot tolerate continuous positive airway pressure may be candidates for mandibular advancement devices or surgical therapies including tracheostomy. Standard HF medications should be used to treat HF, and optimization of fluid balance may help minimize OSA severity. However, it is still unknown whether treatment of OSA in HF patients will reduce hospitalizations or mortality.     

Impact of obstructive sleep apnea on left ventricular diastolic function

The aim of this study was to investigate the impact of obstructive sleep apnea (OSA) on left ventricular (LV) functional changes by using tissue Doppler imaging-derived indexes in patients with OSA. We studied 62 patients classified into 3 groups, namely 18 with mild to moderate OSA, 24 with severe OSA, and 20 control subjects without OSA according to the apnea-hypopnea index (AHI) on complete overnight polysomnogram. All underwent conventional and tissue Doppler echocardiographies. Only early diastolic velocity (Ea; -6.2 +/- 0.3 vs -7.1 +/- 0.3 vs -7.3 +/- 0.3 cm/s, respectively, for the 3 groups, p = 0.023) was significantly decreased in the severe OSA group. Other echocardiographic parameters of diastolic function such as isovolumic relaxation time, deceleration time, mitral inflow early/late wave velocity ratio, and pulmonary vein systolic/diastolic pulmonary vein velocity ratio were comparable among the 3 groups. AHI was correlated only with tissue Doppler imaging-derived indexes of LV diastolic function (Ea r = -0.382, p = 0.002; Ea/late diastolic velocity r = -0.329, p = 0.009), but not with conventional Doppler indexes. AHI remained a significant predictor of Ea after adjusting for age, heart rate, fasting glucose level, blood pressure, body mass index, and LV mass index in a multiple stepwise linear regression model (p = 0.007). In conclusion, only patients with severe OSA showed a greater impairment of LV diastolic function. Of all echocardiographic parameters of diastolic dysfunction investigated, only Ea was identified as the best index to demonstrate an association between LV diastolic dysfunction and severity of OSA independently of body mass index, diabetes mellitus, and hypertension.     

The relationship between sleep arousal,ambulatory blood pressure and heart failure in elderly patients with obstructive sleep apnea

<正>Objective To evaluate the relationship between sleep arousal,ambulatory blood pressure and new-onset heart failure (NOHF) in elderly patients with obstructive sleep apnea (OS A).Methods A total of 584 elderly patients with OSA who were diagnosed and treated in our hospital between March 2015 and March 2019 were prospectively and consecutively selected,     

Prognosis of patients with heart failure and obstructive sleep apnea treated with continuous positive airway pressure

BACKGROUND: Therapy with continuous positive airway pressure (CPAP) provides several benefits for patients with heart failure (HF) complicated by obstructive sleep apnea (OSA). However, the effect on the prognosis of such patients remains unknown. Aims: To determine whether CPAP therapy and compliance affects the prognosis of HF patients with OSA. METHODS: We classified 88 patients with HF and moderate-to-severe OSA into a CPAP-treated group (n = 65) and an untreated group (n = 23), and then those treated with CPAP were further subclassified according to CPAP therapy compliance. The frequency of death and hospitalization was analyzed using multivariate analysis. RESULTS: During a mean (+/- SD) period of 25.3 +/- 15.3 months, 44.3% of the patients died or were hospitalized. Multivariate analysis showed that the risk for death and hospitalization was increased in the untreated group (hazard ratio [HR], 2.03; 95% confidence interval [CI], 1.07 to 3.68; p = 0.030) and in less compliant CPAP-treated patients (HR, 4.02; 95% CI, 1.33 to 12.2; p = 0.014). CONCLUSION: Therapy with CPAP significantly reduced the risk of death and hospitalization among patients with HF and OSA. However, reduced compliance with CPAP therapy was significantly associated with an increased risk of death and hospitalization.