Obstructive sleep apnea, lipoprotein(a) and long-term cardiovascular outcomes in acute coronary syndrome

STUDY OBJECTIVES: The impact of obstructive sleep apnea (OSA) on subsequent cardiovascular events in patients with acute coronary syndrome (ACS) remains debated. This study aims to investigate whether the association of OSA with cardiovascular events is affected by lipoprotein (a) [Lp(a)] levels. METHODS: This is a sub-analysis of prospective cohort study (OSA-ACS, NCT03362385) enrolled ACS patients. OSA defined as an apnea-hypopnea index ≥15 events/h. The effects of OSA on subsequent cardiovascular outcomes were evaluated across varying Lp(a) thresholds. Coronary plaque features by coronary computed tomography angiography were also analyzed. RESULTS: A total of 1137 patients were enrolled, 608 patients (53.5%) were diagnosed with OSA. At a median follow-up of 3.6 years, OSA was associated with a higher risk of major adverse cardiovascular and cerebrovascular events (MACCE) in patients with Lp(a) level > median (HR 1.59, 95% CI 1.12-2.26, p=.009), but not in patients with Lp(a) level ≤ median (HR 1.09, 95% CI 0.80-1.49, p=.60). There were consistent increases in HRs for MACCE in the OSA group with Lp(a) levels rising, as stratified by tertiles or quartiles of Lp(a). In patients with Lp(a) level > median, OSA demonstrated a higher prevalence of ≥1 high-risk plaque (HRP) feature (51.4% vs. 33.3%, p=.03) and low-attenuation plaque (50.0% vs. 32.8, p=.04) per vessel than non-OSA. CONCLUSION: OSA was associated with a continuously increased cardiovascular risk and a higher prevalence of HRP features as Lp(a) levels rose. Lp(a) may help identify ACS patients at higher cardiovascular risk, in whom the efficacy of OSA treatment should be further investigated.