The Importance of Apneic Events in Obstructive Sleep Apnea Associated with Acute Coronary Syndrome

BACKGROUND: Obstructive sleep apnea (OSA) is a potential cardiovascular risk factor. However, there is currently no prominent screening strategy for its diagnosis in patients with acute coronary syndrome (ACS). The aim of this study was to establish the impact of apneic events in case of OSA associated with ACS. METHODS: Between January 1st and June 30th, fifty-three subjects with ACS (first acute myocardial infarction) were prospectively evaluated for OSA. Each patient was evaluated by polysomnography (PSG) two months after the ACS. RESULTS: Mean age of 59±9,6 years, 81,1% males, BMI at 28,5±4,2 kg/m(2), neck circumference of 42,5±12,6 cm, and waist circumference os 102,5±16,5 cm. The majority of patients (73,6%) had moderate to severe OSA (apnea-hypopnea index (AHI) ≥ 15/h and arousal index ≥ 10/h). We defined the apneic coefficient (AC) as the ratio between apnea index (AI) and AHI. We chose as cut-off the median value of apnea coefficient in our population which was at 37%. The patients with a higher AC (AC ≥ 37% versus AC < 37%) had higher levels of Troponin-I (63,4±63,2 versus 29,7±36,1 ng/mL, p=0,016), higher levels of NT-proBNP (1879,8±2141,8 versus 480±621,3 pg/mL, p=0,001), higher SYNTAX score (15,8±11,5 versus 10,2±5,9, p=0,049), and lower left ventricle ejection fraction (LVEF 53,3±11,4 versus 59,4±6,4%, p=0,023) and were more likely to have a STEMI (21 patients (77,7%) vesus 14 patients (53,8%), p=0,031). CONCLUSION: An apneic coefficient (AI/AHI) ≥ 37% is correlated with more severe cardiac impairment, as well as higher hypoxemia and arousal index.