PAP therapy does not improve survival in HFrEF patients with CSA
- related: Sleep and Sleep Disordered Breathing
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This patient has heart failure with reduced ejection fraction (HFrEF) due to prior ischemic cardiomyopathy. The fluctuation in respiratory rate and SpO2 during the clinic visit is suggestive of periodic breathing of the Cheyne-Stokes type. The 5-min excerpt confirms the Cheyne-Stokes breathing pattern with central sleep apnea during sleep. The patient had severe central sleep apnea, with a central apnea index of 55 events per hour of sleep. As illustrated in Figure 1, apneas are characterized by lack of nasal and oronasal flow of air. The concomitant lack of effort on the thoracic and abdominal effort belts confirms the central nature of the apneas. The central apneas in Cheyne-Stokes respiration associated with HFrEF have a very typical crescendo-decrescendo pattern, starting with shallow slow breathing and evolving to rapid deep breathing followed by shallow slow breathing evolving into a central apnea. This cycle typically lasts 60 s or longer from the beginning of an apnea to the next one. There was no evidence of OSA or of inspiratory or expiratory flow limitation on the nasal pressure signal. The snoring channel showed turbulent flow during the hyperpnea phase of Cheyne-Stokes respiration.
Cheyne-Stokes breathing pattern can be present during wakefulness and worsen during non–rapid eye movement sleep and supine sleep. None of the modalities of positive airway pressure (PAP) therapy have been shown to improve survival in patients with predominantly central sleep apnea in the setting of HFrEF.
On the other hand, if this patient's sleep-disordered breathing was predominantly obstructive in nature (ie, more than 50% of the apnea-hypopnea index being obstructive apneas and obstructive hypopneas), CPAP therapy would be appropriate. Since this patient does not have predominantly OSA, and given that there are no effective PAP treatments for Cheyne-Stokes respiration and central sleep apnea in patients with HFrEF, it is best not to prescribe any form of PAP therapy to treat this patient's sleep-disordered breathing. In the Canadian Continuous Positive Airway Pressure for Patients with Central Sleep Apnea and Heart Failure randomized clinical trial, in patients with HFrEF and central sleep apnea, CPAP did not improve survival when compared with usual care.
Adaptive servoventilation during sleep is highly effective in abolishing central sleep apnea in HFrEF, but it has been associated with increased all-cause and cardiovascular mortality in this patient population, particularly in those with a left ventricular ejection fraction <35%.
Given that adaptive servoventilation is an advanced form of bilevel PAP therapy with a backup respiratory rate, there is a clear rationale not to prescribe bilevel PAP spontaneous timed mode in this patient population as well.
Currently, studies evaluating therapies that target resolution of Cheyne-Stokes respiration and central sleep apnea in patients with HFrEF have not shown any improvement in survival. The Food and Drug Administration approved transvenous phrenic nerve stimulation for the treatment of central sleep apnea, but data on long-term mortality are lacking. In this patient population, the goal should be to maximize management of HFrEF. This patient is on reasonable guideline-directed medical therapy for HFrEF. His BP and heart rate are well controlled, and there is no evidence of fluid overload. His type 2 diabetes is well controlled, and he is on treatment for dyslipidemia. The patient has clear indications for an implantable cardioverter-defibrillator, which has been shown to improve survival by decreasing the risk of sudden cardiac death in HFrEF due to ischemic cardiomyopathy, particularly when the left ventricular ejection fraction is <30%.
A few small studies have reported low flow supplemental oxygen during sleep can improve central sleep apnea in HFrEF. However, there is no evidence that supplemental oxygen therapy during sleep can improve survival in patients with Cheyne-Stokes respiration with central sleep apnea in the setting of HFrEF.1