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

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

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.

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.

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.

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.