Sleep apnea in acute coronary syndrome: High prevalence but low impact on 6-month outcome

Abstract

Background and purpose We postulate that the prevalence of sleep-disordered breathing (SDB) in subjects admitted with acute coronary syndrome (ACS) is high, self-report of SDB symptoms is helpful in identifying patients with ACS at risk for SDB, and prospective risk for adverse ACS outcomes is associated with SDB. Patients and methods Consecutive patients admitted to the VA hospital with ACS over ∼1 year were invited to participate. The Cleveland sleep habits questionnaire was administered, and a portable sleep study (Eden-trace, Level 3 monitoring) was performed within 72 h of admission. Results Of 104 patients with complete and adequate sleep studies, 66.4% had an apnea–hypopnea index (AHI) >10/h, and 26.0%, an AHI>30 with the prevalent apnea pattern being obstructive (72.1%). Neither pre-test probability for sleep apnea per questionnaire ( P=0.67) nor degree of subjective sleepiness ( P=0.83) predicted SDB. Although symptoms of dyspnea and paroxysmal nocturnal dyspnea were significantly higher in SDB (AHI≥10) compared to non-SDB (AHI<10) 6 months after admission for ACS, odds of readmission were not significantly different, and this lack of association persisted after covariate adjustment. The factors predicating readmission, but only at 1 month, were age and diabetes. Conclusions In the setting of ACS, the prevalence of SDB was very high in this population and was not detected by self-reports of sleepiness or composite risk for SDB. The odds of adverse outcome for ACS up to 6 months were no different in patients with SDB compared to those without SDB, as compared to effects of an older age or presence of diabetes.