Impact of OSA on Outcomes in Acute Coronary Syndrome

Elucidating the effects of obstructive sleep apnea (OSA) on cardiovascular outcomes in acute coronary syndrome (ACS) is crucial in risk assessments and therapeutic recommendations for affected individuals. Although large epidemiological studies have reported an association between OSA and both coronary heart disease (CHD) and heart failure (HF), its effect on outcomes in ACS is still unclear. In contrast to previous theories attributing causation to OSA, recent studies have hypothesized a cardio protective role of OSA. Repetitive hypoxemic episodes noted in OSA may lead to myocardial ischemic preconditioning, possibly by increasing coronary collateral vessel recruitment, conferring protection from acute coronary events. We propose a prospective, observational, single center study in patients presenting with ACS, including ST segment elevation (STEMI), non-ST segment elevation (NSTEMI) and unstable angina who undergo coronary revascularization to determine the impact of OSA on clinical outcomes after ACS. Adult patients above age 18 years who present with myocardial infarction are eligible. Recruited patients will undergo an overnight sleep study using a level III portable diagnostic device before hospital discharge. The sleep tracings will be analyzed and audited by a certified sleep physician. The patients will be divided into 2 groups based on apnea-hypopnea index (AHI): OSA (AHI ≥ 15) and non-OSA (AHI \< 15) groups. The primary end points of this study were in-hospital, 30 day and 6 month major adverse cardiovascular events (MACE), defined as a composite endpoint of cardiovascular death, non-fatal MI, stroke and the need for unplanned repeat revascularization. Secondary endpoints include individual MACE outcomes of cardiovascular death, non-fatal MI, stroke, need for unplanned repeat revascularization, heart failure requiring hospitalization, and all-cause mortality.