Effects of continuous positive airway pressure on cardiovascular outcomes in heart failure patients with and without Cheyne-Stokes respiration

Sleep Research Laboratory of the Toronto Rehabilitation Institute, Department of Medicine at the Toronto General Hospital (University Health Network), University of Toronto, Ontario, Canada.
Circulation (Impact Factor: 14.95). 08/2000; 102(1):61-6. DOI: 10.1161/01.CIR.102.1.61
Source: PubMed

ABSTRACT Continuous positive airway pressure (CPAP) improves cardiac function in patients with congestive heart failure (CHF) who also have Cheyne-Stokes respiration and central sleep apnea (CSR-CSA). However, the effects of CPAP in CHF patients without CSR-CSA have not been tested, and the long-term effects of this treatment on clinical cardiovascular outcomes are unknown.
We conducted a randomized, controlled trial in which 66 patients with CHF (29 with and 37 without CSR-CSA) were randomized to either a group that received CPAP nightly or to a control group. Change in left ventricular ejection fraction (LVEF) from baseline to 3 months and the combined mortality-cardiac transplantation rate over the median 2.2-year follow-up period were compared between the CPAP-treated and control groups. For the entire group of patients, CPAP had no significant effect on LVEF, but it was associated with a 60% relative risk reduction (95% confidence interval, 2% to 64%) in mortality-cardiac transplantation rate in patients who complied with CPAP therapy. Stratified analysis of patients with and without CSR-CSA revealed that those with CSR-CSA experienced both a significant improvement in LVEF at 3 months and a relative risk reduction of 81% (95% confidence interval, 26% to 95%) in the mortality-cardiac transplantation rate of those who used CPAP. CPAP had no significant effect on either of these outcomes in patients without CSR-CSA.
CPAP improves cardiac function in CHF patients with CSR-CSA but not in those without it. Although not definitive, our findings also suggest that CPAP can reduce the combined mortality-cardiac transplantation rate in those CHF patients with CSR-CSA who comply with therapy.

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    • "Patients with heart failure (HF) frequently have both central sleep apnea (CSA) and obstructive sleep apnea during asleep [1] [2]. Sleep apnea causes repetitive episodes of hypoxia and arousal from sleep, thereby activating the sympathetic nervous system to result in a predisposition to arrhythmias; thus sleep apnea might comprise an independent risk factor for major cardiac events [3] [4] [5]. "
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    ABSTRACT: Background: Adaptive servo-ventilation (ASV) can improve ventilatory inefficiency and exercise oscillatory ventilation (EOV) in patients with heart failure (HF) and central sleep apnea (CSA). Although these improvements might originate from both increase in cardiac function and decrease in sympathetic nerve activity, mechanisms underlying the interrelationship remain unknown. Methods: We compared cardiopulmonary exercise test, muscle sympathetic nerve activity (MSNA) and echocardiography findings at baseline and 3.5. ±. 0.8. months (mean. ±. SD) of follow-up in 28 patients with both HF (New York Heart Association functional class II and III; left ventricular ejection fraction (LVEF). <. 45%) and CSA (apnea-hypopnea index (AHI). ≥. 15/h). Of these, 17 patients consented (ASV group) and 11 patients declined (non-ASV group) to undergo ASV treatment. Compliance with ASV and changes in AHI were determined from data collected by integral counters. Results: VE/VCO2-slope and EOV amplitude at baseline were positively correlated with MSNA, but not with LVEF. ASV therapy reduced VE/VCO2-slope and EOV amplitude (both p<0.01) in association with decrease in MSNA (p<0.01) and increase in LVEF (p<0.001). In non-ASV group, however, these parameters remained unchanged. Change in VE/VCO2-slope was correlated with both change in AHI and average use of ASV. By contrast, change in EOV amplitude was correlated with change in AHI. Changes in VE/VCO2-slope and EOV amplitude were correlated with changes of MSNA (p<0.05), but not with those in LVEF. Conclusions: ASV improves ventilatory inefficiency and EOV probably via suppression of CSA and its sympathoinhibitory effect.
    12/2013; 1. DOI:10.1016/j.ijcme.2013.11.001
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    • "Directly treating CSB in patients with heart failure is associated with improved cardiac outcomes, but an improvement in survival has not been confirmed (Arzt and Bradley, 2006). The use of continuous positive airway pressure (CPAP) can provide improvements in cardiac function in HF patients with CSB (Arzt et al., 2007), but not in those with normal breathing patterns, or in those patients whose CSB is not eliminated with CPAP (non-responders) (Sin et al., 2000). Further, CPAP responders exhibit considerably improved survival compared to CPAP non-responders (Arzt et al., 2007) and untreated controls; yet there is also the possibility that CPAP responders have a survival advantage based on a less severe ventilatory control instability via a less severe cardiac condition. "
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    ABSTRACT: Control of ventilation dictates various breathing patterns. The respiratory control system consists of a central pattern generator and several feedback mechanisms that act to maintain ventilation at optimal levels. The concept of loop gain has been employed to describe its stability and variability. Synthesizing all interactions under a general model that could account for every behavior has been challenging. Recent insight into the importance of these feedback systems may unveil therapeutic strategies for common ventilatory disturbances. In this review we will address the major mechanisms that have been proposed as mediators of some of the breathing patterns in health and disease that have raised controversies and discussion on ventilatory control over the years.
    Respiratory Physiology & Neurobiology 05/2013; 189(2). DOI:10.1016/j.resp.2013.04.020 · 1.97 Impact Factor
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    • "Although initial results with continuous positive airway pressure (CPAP) therapy to treat CSR were promising [12], the subsequent CANPAP (CANadian continuous Positive Airway Pressure) trial failed to show a positive impact on mortality in CPAP-tre ated HF patients with CSR [13]. Despite an improvem ent in nocturnal oxygenati on, lowered norepinephrine plasma levels, and better performanc e in six-minute walking tests, mortality was not improved [13]. "
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    ABSTRACT: BACKGROUND: Sleep-disordered breathing (SDB) in patients with heart failure (HF) is of major prognostic impact, though treatment of simultaneously occurring central and mixed apnea events is challenging. The objective was to examine long-term effects of a new trilevel adaptive servoventilation (ASV) therapy in patients with systolic or diastolic HF. METHODS: A total of 45 consecutive patients with a history of HF, elevated N-terminal prohormone of brain natriuretic peptide levels, objective signs of cardiac dysfunction, and moderate to severe SDB (apnea-hypopnea index [AHI] ⩾15/h) with combined central and mixed respiratory events were included in this study and ASV therapy (SOMNOvent CR, Weinmann) was offered. RESULTS: In 38 patients (84%), ASV therapy was successfully initiated, with 23 (51%) patients showing appropriate compliance (device use ⩾4h/night for ⩾5d/w) after 3.6±1.2months. In these patients ASV therapy and HF status were re-evaluated. A sustained reduction was achieved in AHI (42.8±17.5/h vs 8.9±5.8/h; p<0.001) and oxygen saturation. Improvements also were recorded in New York Heart Association (NYHA) functional class (2.4±0.5-1.9±0.4; p<0.001) and oxygen uptake during cardiopulmonary exercise testing (VO2 peak, 13.64±3.5-15.8±5.8ml/kg/min; p<0.002). CONCLUSION: In selected HF patients, trilevel ASV therapy is able to treat SDB with combined central and mixed respiratory events. This treatment is associated with an improvement in HF symptoms and objective cardiopulmonary performance.
    Sleep Medicine 02/2013; 14(5). DOI:10.1016/j.sleep.2012.12.013 · 3.10 Impact Factor
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