[Prevalence and predictors of obstructive sleep apnea in patients admitted for acute myocardial infarction].

BACKGROUND: Obstructive sleep apnea has been implicated in the pathogenesis and aggravation of coronary atherosclerosis. However, it remains underdiagnosed in cardiology practice.

AIM: The aim of this study was to determine the prevalence of obstructive sleep apnea and the predictors of severe sleep apnea in patients admitted for ST elevation myocardial infarction.

METHODS: This was a prospective study which has included 120 patients hospitalized for ST elevation myocardial infarction, from April 2011 to March 2012. All patients have undergone an overnight sleep study using a portable polygraphy device, in the 15 days following the acute coronary syndrome. The diagnostic of obstructive sleep apnea was considered as apnea-hypopnea index of ≥ 5 events per hour, severe sleep apnea was defined as apnea -hypopnea index of ≥ 30. Subjective daytime sleepiness was assessed by the Epworth sleepiness scale. All patients have had an oxygen saturation monitoring in the coronary care unit using a pulse oxymeter, before undergoing the sleep study.

RESULTS: The study population was made up of 102 men and 18 women. The mean age was 58 ± 12 years. Smoking was the major cardiovascular risk factor found in 72% of all patients, diabetes and hypertension were represented in 40% and 44% of the population, respectively. Eighty-seven percent of patients were admitted in the first 24 hours of symptom onset. A primary percutaneous coronary intervention was performed in 60% of cases while fibrinolysis was done in 10% of patients. The prevalence of obstructive sleep apnea was 79%. Mean apnea-hypopnea index was 15.76 ± 14.93 and severe form was diagnosed in 16% of all patients. Multivariate analysis showed that Epworth sleepiness score of ≥ 4 and nocturnal desaturation below 82% were independent predictive factors for severe obstructive sleep apnea.

CONCLUSION: Prevalence of obstructive sleep apnea was very high in patients admitted for acute myocardial infarction. Epworth sleepiness score of ≥ 4 and nocturnal desaturation below 82% were independent predictive factors for severe form of sleep apnea.