Obstructive Sleep Apnea (OSA) is frequently associated with cardiovascular disease. Its diagnosis seems to be related with poor prognosis.

To determine the prevalence of OSA in patients with acute coronary syndrome (ACS). Evaluate the prognostic impact of OSA and CPAP therapy in these patients.

Prospective study of 73 patients diagnosed with ACS. A polysomnography was performed in all patients. An Apnea-hypopnea index>5 was considered diagnostic of OSA and patients were referred to CPAP therapy. We evaluated the occurrence of the primary composite endpoint of death, myocardial infarction and revascularization.

The prevalence of OSA was 63.0%. The average age (62.4±11.3) was similar in both groups. Gender and cardiovascular risk factors were not significantly different between groups. Patients were admitted for Non-ST elevation ACS in 60.3% and for ST elevation ACS in 39.7%. OSA was classified as mild (OSA-M) in 30.4% and as moderate to severe (OSA-S) in 69.6%. After a median follow-up of 75 months (IQR 71-79), patients with OSA-S showed a significantly higher incidence of the composite endpoint (relative risk 3.29, 95% CI 1.07-10.10; p=0.038). Kapplan-Meier survival curves are represented in Figure 1. Adherence to CPAP was 42.9% and there was a numerically lower proportion of patients with composite endpoint in the group of compliant patients (33.3% vs. 37.5%, p=NS).

OSA has a high prevalence in ACS patients. Its screening has high diagnostic yield and allows to identify patients with clearly unfavorable prognosis and a potentially treatable risk factor. CPAP notes a significant number of noncompliant, but may improve prognosis, justifying further randomized clinical studies.