Effect of Obstructive Sleep Apnea and CPAP Treatment on Cardiovascular Outcomes in Acute Coronary Syndrome in the RICCADSA Trial

We aimed to address the impact of OSA and its treatment with continuous positive airway pressure (CPAP) on major adverse cardiovascular and cerebrovascular events (MACCE) in patients with acute coronary syndrome (ACS). In this current analysis of the revascularized ACS subgroup (n = 353) of the Randomized Intervention with CPAP in Coronary Artery Disease and Obstructive Sleep Apnea (RICCADSA) trial (Trial Registry: ClinicalTrials.gov; No: NCT 00519597), participants with non-sleepy OSA (apnea-hypopnea-index [AHI] ≥ 15 events/h on a home sleep apnea testing, and Epworth Sleepiness Scale [ESS] score < 10; n = 171) were randomized to CPAP (n = 86) or no-CPAP (n = 85). The sleepy OSA patients (AHI ≥ 15 events/h and ESS ≥ 10) who were offered CPAP, and the ones with no-OSA (AHI < 5 events/h) were included in the observational arm. A post-hoc analysis was done to compare untreated OSA (no-CPAP; n = 78) and nonadherent sleepy/non-sleepy OSA (n = 96) with the reference group without OSA (n = 81). The primary endpoint (the first event of repeat revascularization, myocardial infarction, stroke or cardiovascular mortality) during a median 4.7-year follow-up was evaluated in time-dependent Cox proportional hazards models adjusted for confounding factors. The incidence of MACCE did not differ significantly in intention-to-treat population. On-treatment analysis showed a significant risk reduction in those who used CPAP for ≥4 vs. <4 h/day or did not receive treatment (adjusted hazard ratio [HR] 0.17; 95% confidence interval [CI] 0.03–0.81; p = 0.03). Compared with the reference group, nonadherent/untreated OSA was associated with an increased cardiovascular risk (adjusted HR 1.97, 95% CI 1.03–3.77; p = 0.04). We conclude that OSA is an independent risk factor for adverse cardiovascular outcomes in patients with ACS. CPAP treatment may reduce this risk, if the device is used at least 4 h/day.