Elevated serum copper improves risk stratification for high-risk plaques identified by optical coherence tomography in chronic coronary syndromes

INTRODUCTION: Chronic coronary syndrome (CCS) refers to a spectrum of clinical manifestations of coronary artery disease, excluding acute coronary syndrome (ACS), which is characterized by acute thrombosis. Identifying risk factors associated with plaque stability is crucial for preventing progression of CCS to ACS. OBJECTIVES: This study aimed to explore the associations between serum copper levels and high‑risk plaque (HRP) in patients with CCS, and to evaluate the potential of serum copper level as a novel diagnostic biomarker for HRP. PATIENTS AND METHODS: In this cross‑sectional study, 80 CCS patients undergoing coronary angiography were enrolled. Plaque characteristics were systematically assessed using optical coherence tomography (OCT), and inflammatory parameters and serum copper concentrations were measured. Logistic regression models were employed to examine the association between variables and HRP. Receiver operating characteristic analysis was used to evaluate the discriminatory performance of biomarkers. RESULTS: HRP was detected in 39 patients (48.8%). Serum copper levels were significantly higher in the HRP group than in the stable plaque group. Copper levels correlated positively with interleukin 6 (IL‑6) and matrix metalloproteinase‑9, and inversely with IL‑10 levels. Serum copper level was an independent predictor of HRP and showed good discriminatory ability. A biomarker panel combining serum copper, low‑density lipoprotein cholesterol (LDL‑C), and IL‑6 achieved an area under the curve of 0.864, which was significantly superior to any single biomarker alone. CONCLUSIONS: Elevated serum copper level is independently associated with OCT‑defined HRP in CCS patients. A combined model incorporating copper, LDL‑C, and IL‑6 significantly improves the noninvasive identification of HRP, suggesting a potential multimarker strategy for risk stratification in CCS.