Clinical and polysomnographic determinants of REM predominant obstructive sleep apnoea and response to treatment in a revascularized coronary artery disease cohort

Abstract

Background: Obstructive sleep apnoea (OSA) is common in patients with coronary artery disease (CAD). OSA occurring predominantly during rapid-eye movement (REM) sleep has been associated with increased cardiovascular morbidity. Clinical features of this phenotype among CAD patients is unknown.

Aims and Objective: We addressed the determinants of REM-predominant OSA and its association with cardiovascular outcomes in a CAD cohort.

Methods: The current study was a secondary analysis of the RICCADSA trial, conducted in Sweden between 2005 and 2013. Out of 511 patients, 399 had OSA, based on an Apnoea-Hypopnoea-Index (AHI)≥15/hr on home-sleep apnoea testing. Polysomnography was conducted in the OSA group, of whom 286 with total sleep time≥240 min, and REM sleep≥30 min, were included in the current protocol. REM- predominant OSA was defined as an REM-AHI/non-REM AHI≥2.

Results: In all, 73 (25.5%) had REM-predominant OSA. They were more likely to be female (26.0% vs 9.9%; p=0.001), and more obese (42.5% vs 24.4%; p=0.003) but had lower AHI (24.0/hr vs 40.9/hr; p<0.001) and less reduction in Slow-Wave Sleep (10.7% vs 6.9%; p=0.046) compared to the patients without REM-predominant OSA. There were no significant differences between the groups with regard to age, excessive daytime sleepiness, mood, comorbidities, cardiac function, inflammatory biomarkers and adherence to continuous positive airway pressure treatment. No between-group differences were observed with regard to cardiovascular outcomes.

Conclusions: REM-predominant OSA is not associated with increased cardiovascular morbidity in patients with an already established CAD.