Elevated Remnant Cholesterol Predicts Poor Outcome in Patients with Premature Acute Coronary Syndrome：A Retrospective, Single-Center Study

Background The association of remnant cholesterol (RC) with recurrent cardiovascular events following acute coronary syndrome (ACS) is well documented. However, no RC-stratified analysis focused on patients with premature ACS (PACS). Objectives This study sought to elucidate the clinical characteristics and subsequent cardiovascular events in high RC and low RC with PACS. Methods In this retrospective cohort study, we consecutively recruited 820 PACS patients between January 2019 and January 2020. RC was calculated as total cholesterol minus high-density lipoprotein cholesterol minus low-density lipoprotein cholesterol. RC ≥ 66.6 percentile of the cohort was defined as high RC. The primary endpoint was major adverse cardiovascular and cerebrovascular event (MACCE), including cardiovascular death, myocardial infarction (MI), stroke, ischemia-driven revascularization, or hospitalization for unstable angina or heart failure. Results Among 820 patients enrolled, 277 (33.8%) were high RC and 543 (66.2%) were low RC. High RC had higher prevalence of traditional risk factors including diabetes (33.6% vs 27.3%, p = 0.04), hypertension (68.2% vs 61.3%, p = 0.04), and hyperlipidemia (43.3% vs 31.3%, p = 0.001). The levels of glucose (p < 0.001), hemoglobin A1C (p = 0.005), triglyceride (p < 0.001), total cholesterol (p < 0.001) and LDL-C (p = 0.017) in high RC group were significantly higher than those in low RC group, while the levels of HDL-C (p = 0.001) were lower. During 3 years of follow-up, high RC, compared with low RC, have a significantly higher cumulative incidence of MACCE (16.2% vs 10.9%; adjusted HR 1.68, 95% CI 1.10–2.59; p = 0.02). The increased risk of MACCE in high RC was primarily attributable to significantly higher rates of hospitalization for unstable angina (12.3% vs 7.9%; adjusted HR 1.69, 95% CI 1.03–2.75; p = 0.03) and composite for cardiac events including cardiovascular death, MI, ischemia-driven revascularization or hospitalization for unstable angina or heart failure (14.8% vs 9.8%; adjusted HR 1.75, 95% CI 1.12–2.73; p = 0.01). Conclusions In hospitalized PACS patients, the cumulative incidence of MACCE in high RC patients was significantly higher than that in low RC patients during a median follow-up of nearly 3 years. The incremental risk in high RC might be explained by significantly higher rates of hospitalization for unstable angina and composite for cardiac events. Therefore, we should pay close attention to the indicator of RC and pursue further exploration.