Differing effects of obstructive and central sleep apneas on stroke volume in patients with heart failure

Respiratory sleep disorders in patients with congestive heart failure

Respiratory sleep disorders (RSD) occur in about 40-50% of patients with symptomatic congestive heart failure (CHF). Obstructive sleep apnea (OSA) is considered a cause of CHF, whereas central sleep apnea (CSA) is considered a response to heart failure, perhaps even compensatory. In the setting of heart failure, continuous positive airway pressure (CPAP) has a definite role in treating OSA with improvements in cardiac parameters expected. However in CSA, CPAP is an adjunctive therapy to other standard therapies directed towards the heart failure (pharmacological, device and surgical options). Whether adaptive servo controlled ventilatory support, a variant of CPAP, is beneficial is yet to be proven. Supplemental oxygen therapy should be used with caution in heart failure, in particular, by avoiding hyperoxia as indicated by SpO2 values >95%.

Heterogenous haemodynamic effects of adaptive servoventilation therapy in sleeping patients with heart failure and Cheyne-Stokes respiration compared to healthy volunteers

This study investigated the haemodynamic effects of adaptive servoventilation (ASV) in heart failure (HF) patients with Cheyne-Stokes respiration (CSR) versus healthy controls. Twenty-seven HF patients with CSR and 15 volunteers were ventilated for 1 h using a new ASV device (PaceWave™). Haemodynamics were continuously and non-invasively recorded at baseline, during ASV and after ventilation. Prior to the actual study, a small validation study was performed to validate non-invasive measurement of Stroke volume index (SVI). Non-invasive measurement of SVI showed a marginal overall difference of -0.03 ± 0.41 L/min/m(2) compared to the current gold standard (Thermodilution-based measurement). Stroke volume index (SVI) increased during ASV in HF patients (29.7 ± 5 to 30.4 ± 6 to 28.7 ± 5 mL/m(2), p < 0.05) and decreased slightly in volunteers (50.7 ± 12 to 48.6 ± 11 to 47.9 ± 12 mL/m(2)). Simultaneously, 1 h of ASV was associated with a trend towards an increase in parasympathetic nervous activity (PNA) in HF patients and a trend towards an increase in sympathetic nervous activity (SNA) in healthy volunteers. Blood pressure (BP) and total peripheral resistance response increased significantly in both groups, despite marked inter-individual variation. Effects were independent of vigilance. Predictors of increased SVI during ASV in HF patients included preserved right ventricular function, normal resting BP, non-ischaemic HF aetiology, mitral regurgitation and increased left ventricular filling pressures. This study confirms favourable haemodynamic effects of ASV in HF patients with CSR presenting with mitral regurgitation and/or increased left ventricular filling pressures, but also identified a number of new predictors. This might be mediated by a shift towards more parasympathetic nervous activity in those patients.

Overnight Effects of Obstructive Sleep Apnea and Its Treatment on Stroke Volume in Patients With Heart Failure

BACKGROUND

We previously showed in heart failure (HF) patients that obstructive respiratory events during sleep and generation of negative intrathoracic pressure during Mueller manoeuvres, mimicking obstructive apneas, acutely reduced stroke volume (SV). We also showed that treating obstructive sleep apnea (OSA) with continuous positive airway pressure (CPAP) increased left ventricular ejection fraction over a 1-month period. We therefore hypothesized that, in HF patients, those with OSA would have greater overnight declines in SV and cardiac output (CO) than in those without sleep apnea, and that therapy of OSA using CPAP would prevent these declines.

METHODS

We examined overnight percent change in SV and CO in 32 HF patients with and 28 without OSA using digital photoplethysmography. Among patients with OSA, we also examined changes in SV and CO during a CPAP titration study.

RESULTS

During the baseline polysomnogram SV and CO decreased more overnight in those with OSA than in those without sleep apnea (-12.6 ± 7.7% vs -3.2 ± 6.8%; P < 0.001 and -16.2 ± 9.9% vs -3.7 ± 8.3%; P < 0.001, respectively). Overnight changes in SV and CO correlated inversely with total apnea-hypopnea index (r = -0.551; P < 0.001 and r = -0.522; P < 0.001, respectively). In 21 patients with OSA, CPAP reduced the total apnea-hypopnea index from 37.7 ± 21.4 to 15.0 ± 16.0 (P < 0.001) in association with attenuation of the overnight reduction of SV (from -14.0 ± 7.9% to -3.4 ± 9.8%; P = 0.002) and CO (from -17.2 ± 9.0% to -9.7 ± 10.7%; P = 0.042).

CONCLUSIONS

In patients with HF, coexisting OSA causes overnight declines in SV and CO that are prevented through reversal of OSA by CPAP.

Linkage of sleep-disordered breathing and acute aortic dissection with patent false lumen

Sleep-disordered breathing (SDB) is known as a cardiovascular risk factor and has high prevalence in hypertension, which is a major risk factor of aortic dissection (AD). However, the impact of SDB on AD has not been fully clarified. The aim of this study is to elucidate the impact of SDB on AD, especially on the type of false lumen in AD. We enrolled twenty-three consecutive patients with acute AD (mean age: 66 ± 13 years). All subjects were evaluated by an ambulatory polygraphic sleep monitoring within 1 month from the onset. AD was evaluated by axial images of computed tomography. We comparatively analyzed SDB and AD. 35 % of the subjects presented severe OSA (apnea-hypopnea index: AHI ≥30). The patent false lumen group showed significantly higher systolic and diastolic blood pressure (BP) on arrival and AHI, and lower percutaneous oxygen saturation (SaO2) compared with those in the thrombosed false lumen group. The prevalence of severe SDB was higher in the patent false lumen group (60 vs 15 %, p = 0.039). Systolic BP on arrival was significantly correlated with AHI (r = 0.457, p = 0.033) and the minimum SaO2 (r = -0.537, p = 0.010). The present study revealed close linkage between SDB and AD, and a high prevalence of SDB among AD patients. Severe SDB was related to the development of AD, especially for the patent false lumen type through highly elevated BP which might be easily evoked in the presence of severe SDB. Repetitive occurrence of intrathoracic negative pressure also might influence the repair or closure of false lumen of AD, although the present analysis did not reach statistical significance.

Sleep apnea in the elderly

PURPOSE OF REVIEW

Sleep apnea syndrome (SAS) in the elderly presents varied clinical symptoms and also has many complications. Moreover, there are many hospital departments related to these symptoms. This article uses literature to provide an outline on SAS observed in the elderly.

RECENT FINDINGS

SAS sufferers often have complications with so-called lifestyle-related diseases, such as hypertension, hyperlipidemia, diabetes mellitus and metabolic syndrome. These symptoms, along with SAS, recede as a result of continuous positive airway pressure treatment. Some have also reported recession of depression symptoms and delay in deterioration of cognitive functions.

SUMMARY

The elderly tends to develop SAS through coexistence of chronic respiratory organ disorders, increase in upper airway collapse, strokes, cardiovascular diseases, hypertension, diabetes mellitus and other physiological anatomical changes that accompany aging. However, judgment on the severity and effects regarding prognosis by each remedy used in the diagnosis and treatment of SAS in the elderly is still being developed, and it is considered necessary to accumulate more evidence and establish new standards.

Impact of sleep-disordered breathing on heart rate turbulence in heart failure patients

Background

Sleep-disordered breathing (SDB) is associated with adverse outcomes in patients with chronic heart failure (CHF). Additionally, heart rate turbulence (HRT) reflects changes in the sinus cycle length of baroreceptor in response to hemodynamic fluctuations after ventricular premature beat. Recent studies have suggested that HRT as a marker of vagal activity has a predictive value of poor prognosis in CHF patients. However, little is known about the relationship between SDB and HRT in CHF patients.

Methods and Results

In this study, 75 patients with CHF were enrolled. We simultaneously performed Holter ECG during a 24-hr period and portable sleep monitoring at nighttime, and determined the respiratory disturbance index (RDI), HRT (turbulence onset (TO) and turbulence slope (TS)) during that 24-hr period. These patients were divided into two groups based on the presence of severe SDB: Group A (RDI≥30, n = 17) and Group B (RDI<30, n = 58). TS was significantly lower in Group A than in Group B across the 24-hr period (nighttime: 3.6±1.1 vs. 6.9±1.3; daytime: 3.7±0.8 vs. 7.0±1.1; all-day: 3.5±0.7 vs. 6.7±0.9% ms/RR, P<0.05, respectively). TO did not differ between the two groups. Furthermore, there was a significant negative correlation between all-day TS and RDI (R = –0.257, P = 0.027). Moreover, in the multiple regression analysis, RDI was an independent factor to determine all-day TS.

Conclusions

In patients with severe SDB, blunted TS was observed across 24 hours. These results suggest that SDB induce impairment of vagal activity across a 24-hour period and may be associated with poor prognosis in CHF patients.

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.