Sleep apnoea and cardiovascular outcomes after coronary artery bypass grafting

Abstract

Objective: Patients with advanced coronary artery disease are referred for coronary artery bypass grafting (CABG) and it remains unknown if sleep apnoea is a risk marker. We evaluated the association between sleep apnoea and major adverse cardiac and cerebrovascular events (MACCE) in patients undergoing non-emergent CABG.

Methods: This was a prospective cohort study conducted between November 2013 and December 2018. Patients from four public hospitals referred to a tertiary cardiac centre for non-emergent CABG were recruited for an overnight sleep study using a wrist-worn Watch-PAT 200 device prior to CABG.

Results: Among the 1007 patients who completed the study, sleep apnoea (defined as apnoea-hypopnoea index ≥15 events per hour) was diagnosed in 513 patients (50.9%). Over a mean follow-up period of 2.1 years, 124 patients experienced the four-component MACCE (2-year cumulative incidence estimate, 11.3%). There was a total of 33 cardiac deaths (2.5%), 42 non-fatal myocardial infarctions (3.7%), 50 non-fatal strokes (4.9%) and 36 unplanned revascularisations (3.2%). The crude incidence of MACCE was higher in the sleep apnoea group than the non-sleep apnoea group (2-year estimate, 14.7% vs 7.8%; p=0.002). Sleep apnoea predicted the incidence of MACCE in unadjusted Cox regression analysis (HR 1.69; 95% CI 1.18 to 2.43), and remained statistically significant (adjusted HR 1.57; 95% CI 1.09 to 2.25), after adjustment for age, sex, body mass index, left ventricular ejection fraction, diabetes mellitus, hypertension, chronic kidney disease and excessive daytime sleepiness.

Conclusion: Sleep apnoea is independently associated with increased MACCE in patients undergoing CABG.

Trial registration number: NCT02701504.

Keywords: cardiac risk factors and prevention; cardiac surgery; chronic coronary disease; coronary artery disease surgery; heart failure.

Conflict of interest statement

Competing interests: None declared.

© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.

Figures

Figure 1

Flow chart of screening and recruitment. All patients who met the inclusion criteria were screened for recruitment. CABG, coronary artery bypass grafting.

Figure 2

Cumulative incidence of the composite primary endpoint of major adverse cardiac and cerebrovascular events (MACCE). Kaplan–Meier plot showing the cumulative incidence of MACCE in patients with sleep apnoea (in red) and in patients without sleep apnoea (in blue).

Figure 3

Cumulative incidence of secondary endpoints. Kaplan–Meier plots showing the cumulative incidences of all-cause mortality (A), cardiovascular mortality (B), sudden cardiac death or resuscitated cardiac arrest (C), and hospitalisation for heart failure (D), respectively, in patients with sleep apnoea (in red) and in patients without sleep apnoea (in blue).