Adaptive servo-ventilation in heart failure patients with sleep apnea: A real world study
Introduction
There is a high prevalence of sleep disordered breathing (SDB) in congestive heart failure (CHF) patients with both mild and severe disease [1], [2], [3]. This manifests as either central (CSA), mixed or obstructive (OSA) sleep apnea/hypopnea [2], [3]. SDB contributes to a poorer prognosis in CHF patients [4], [5] although it is rarely associated with daytime sleepiness [6].
There has been a number of studies reporting the treatment of OSA and CSA in CHF patients with continuous positive airway treatment (CPAP). In CHF patients with OSA, 3 months of CPAP improved left ventricular ejection fraction (LVEF), reduced overnight urinary norepinephrine excretion and improved quality of life [7], [8]. In CHF patients with CSA, CPAP has been shown to reduce the rate of mortality or cardiac transplantation rate [9]; although the outcome of the recent CanPAP trial does not support the routine use of CPAP in CHF patients with CSA [10], [11]. This creates a management dilemma for clinicians treating patients with mixed, but predominantly central, SDB which has yet to be resolved.
Adaptive servo-ventilation (ASV) is designed for treating CSA in CHF patients by providing expiratory positive airway pressure with an inspiratory pressure support that is servo-controlled. ASV has been shown to be more effective than CPAP in reducing CSA in CHF [12], [13]. It is tolerated better than CPAP, decreases plasma brain natriuretic peptide (BNP) and urinary metadrenaline excretion [14]. Longer term use has been shown to improve LVEF and quality of life [13].
This study differs from previous studies as we have assessed cardiopulmonary and quality of life outcomes in CHF patients with both OSA and CSA, following 6 months treatment with optimized ASV. The outcome variables have been compared to a non-randomised untreated comparison group who were mainly CSA patients that were unwilling or unable to tolerate ASV for 6 months. We hypothesized that ASV would be effective at reducing SDB, improve cardiac status and quality of life compared to the comparison group.
Section snippets
Methods
This was a non-randomised, prospective comparison study. Patients were recruited from cardiac clinics at the Royal Brompton and Conquest Hospitals, UK. All patients gave written informed consent and the study was approved by the institutional ethics committee.
Patient recruitment and baseline characteristics
Patient recruitment is shown in Fig. 1. Sixty one patients underwent NPSG as part of a wider study investigating the prevalence of SDB in CHF [1]. Twenty six were recruited into the present study and 22 were offered ASV; 5 patients declined and were moved to the comparison group. Seventeen patients were given an overnight trial of ASV; 3 declined to use the machine at home and were also moved to the comparison group. Fourteen patients were started on home ASV; 2 withdrew due to mask problems
Discussion
The main findings of this study were that in CHF patients with both OSA and CSA ASV reduced all types of SDB, and LVEF increased after 6 months ASV treatment compared to an untreated comparison group; daytime energy/vitality and subjective daytime sleepiness were also improved.
Acknowledgements
This work was supported by the British Heart Foundation, Wellcome Trust and an educational grant from ResMed UK Ltd. The Autoset CS machines and masks were supplied by ResMed UK Ltd. The authors of this manuscript have certified that they comply with the Principles of Ethical Publishing in the International Journal of Cardiology [27].
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