Treating sleep disordered breathing for cardiovascular outcomes: observational and randomised trial evidence

Sleep disordered breathing (SDB) is considered a risk factor for cardiovascular disease (CVD). Obstructive sleep apnoea (OSA) can be treated with continuous positive airway pressure (CPAP), and central sleep apnoea (CSA), in patients with heart failure with reduced ejection fraction (HFrEF), by peak flow-triggered adaptive servo-ventilation. Presently, there is equipoise as to whether treating SDB prevents cardiovascular events. Some propose treatment for this indication, based on observational data, while others argue against because of the lack of randomised trial evidence. This review evaluates literature concerning the cardiovascular effects of treating SDB with PAP devices in individuals with and without CVDs. Nine observational studies report significantly lower cardiovascular event rates in those treated, than in those not treated, for SDB. Conversely, 12 randomised trials in which excessive daytime sleepiness was generally an exclusion criterion showed no reduction in cardiovascular event rates. The SERVE-HF trial showed an increase in mortality with use of minute ventilation-triggered adaptive servo-ventilation for CSA in patients with HFrEF. In the ADVENT-HF trial, treating HFrEF patients with coexisting OSA or CSA using peak flow-triggered adaptive servo-ventilation was safe and improved sleep structure and heart failure-related quality of life but did not reduce all-cause mortality or cardiovascular events. More evidence is required to determine whether treating CSA in patients with HFrEF prevents cardiovascular events and improves survival. Presently, the rationale for treating SDB with PAP remains improving sleep structure and quality of life, as well as relieving excessive daytime sleepiness, but not reducing cardiovascular events.