Sleep apnoea and unscheduled re-admission in patients undergoing coronary artery bypass surgery

- Sleep apnoea was diagnosed in 50% of the patients scheduled to undergo CABG.
- Hypertension, high body mass index and chronic renal failure were independent predictors of sleep apnoea.
- The risk of unscheduled re-admission was higher in patients with sleep apnoea.
- Early screening and treatment of sleep apnoea may improve outcomes after CABG.

IntroductionAlthough it has been recognised as a cardiovascular risk factor, data on sleep apnoea screening before coronary artery bypass grafting (CABG) are scarce. This study sought to determine the prevalence, predictors and effects of sleep apnoea on re-admission in patients undergoing CABG.MethodWe prospectively recruited 152 patients to undergo an overnight sleep study before CABG. Sleep apnoea was defined as an apnoea-hypopnoea index of ≥15 events per hour. Data on unscheduled re-admission due to cardiovascular events were collected.ResultsAmong the 138 patients who completed the sleep study, sleep apnoea was diagnosed in 69 (50%). The patients who had sleep apnoea had a lower left ventricular ejection fraction (p = 0.029), a larger left atrial diameter (p = 0.014) and a larger left ventricular end-systolic dimension (p = 0.019) than those who did not. Angiographic SYNTAX and Gensini scores were similar in patients with and without sleep apnoea. The generalised structural equation model revealed that hypertension, a high body mass index and chronic renal failure were independent predictors of sleep apnoea (p < 0.05). After an average follow-up of 6 ± 3 months, 12 patients with sleep apnoea (17.3%) and three patients without sleep apnoea (4.3%) were involved in unscheduled re-admission. Patients with sleep apnoea were almost five times more likely to have an unscheduled re-admission due to cardiovascular events (adjusted odds ratio: 4.63, 95% CI: 1.24-17.31, p = 0.023) than those without sleep apnoea.ConclusionsSleep apnoea was prevalent and predictive of unscheduled re-admissions in patients scheduled for CABG.