目的 探讨残余胆固醇（RC）对急性冠脉综合征（ACS）患者冠状动脉内薄纤维帽粥样硬化斑块（TCFA）的预测价值，并分析其与斑块易损特征的关系。 方法 回顾性纳入2024年1月至2025年12月在山东第一医科大学附属菏泽医院因胸痛或疑似心肌缺血住院并行冠状动脉造影的患者186例，依据临床诊断与造影结果分为ACS组（n = 117）和非ACS组（n = 69）。ACS组均完成光学相干断层成像（OCT），根据OCT结果分为TCFA组（n = 49）与非TCFA组（n = 68）。比较各组临床与血脂资料，以多因素logistic回归筛选ACS患者冠状动脉内TCFA的独立相关因素，以受试者工作特征（ROC）曲线评价RC对TCFA的预测价值，并用Spearman秩相关分析RC与OCT斑块特征的关联。 结果 ACS组和非ACS组患者总胆固醇（TC）、低密度脂蛋白胆固醇（LDL-C）、RC及高密度脂蛋白胆固醇（HDL-C）水平差异有统计学意义（P < 0.05）。ACS患者中TCFA组吸烟史、糖尿病史比例及TC、LDL-C、RC水平与非TCFA组比较，差异有统计学意义（P < 0.05）。多因素logistic回归分析显示，糖尿病史、吸烟史、LDL-C升高及RC升高（OR = 2.917，95%CI：1.407 ~ 6.048）是ACS患者冠状动脉内TCFA的独立相关因素（P < 0.05）。ROC分析显示，RC预测ACS患者冠状动脉内TCFA的曲线下面积（AUC）为0.702（95%CI：0.600 ~ 0.803），最佳截断值为0.975 mmol/L，敏感度和特异度分别为0.653和0.794。Spearman秩相关分析显示，RC与最大脂质弧度、巨噬细胞浸润呈正相关（r_s = 0.438、0.248，P < 0.05），与最薄纤维帽厚度、最小管腔面积（MLA）呈负相关（r_s = -0.369、-0.342，P < 0.05）。 结论 RC升高是ACS患者冠状动脉内TCFA的独立相关因素，对TCFA具有一定预测价值，并与纤维帽变薄、脂质弧度增大、MLA减小及巨噬细胞浸润增加等斑块易损特征相关。RC可为ACS患者冠状动脉内高危斑块的风险分层提供参考。

Objective To investigate the predictive value of remnant cholesterol （RC） for intracoronary thin-cap fibroatheroma （TCFA） in patients with acute coronary syndrome （ACS） and analyze its relationship with plaque vulnerability features. Methods A total of 186 patients who were hospitalized for chest pain or suspected myocardial ischemia and underwent coronary angiography at Heze Hospital Affiliated to Shandong First Medical University from January 2024 to December 2025 were retrospectively enrolled. These patients were divided into an ACS group （n = 117） and a non-ACS group （n = 69） based on clinical and angiographic findings. All ACS patients underwent optical coherence tomography （OCT） and were further classified into a TCFA group （n = 49） and a non-TCFA group （n = 68）. Clinical data and lipid profiles were compared among the groups. Multivariable logistic regression was employed to identify independent factors for intracoronary TCFA， ROC curve analysis was used to evaluate the predictive value of RC， and Spearman rank correlation was utilized to assess the associations between RC and OCT-derived plaque features. Results Total cholesterol （TC）， low-density lipoprotein cholesterol （LDL-C）， remnant cholesterol （RC）， and high-density lipoprotein cholesterol （HDL-C） exhibited significant differences between the ACS and non-ACS groups （P < 0.05）. Among ACS patients， the TCFA group significantly differed from the non-TCFA group in terms of the proportions of patients with a history of smoking and diabetes mellitus， as well as the levels of TC， LDL-C， and RC （P < 0.05）. Multivariable analysis revealed that diabetes， smoking， elevated LDL-C， and elevated RC （odds ratio ［OR］ = 2.917， 95% confidence interval ［CI］： 1.407 - 6.048） were independent risk factors for intracoronary TCFA （P < 0.05）. Receiver operating characteristic （ROC） curve analysis demonstrated that the area under the curve （AUC） of RC for predicting intracoronary TCFA was 0.702 （95%CI： 0.600 ? 0.803）， with an optimal cutoff value of 0.975 mmol/L， a sensitivity of 0.653， and a specificity of 0.794. Spearman rank correlation analysis indicated that RC was positively correlated with the maximum lipid arc and macrophage infiltration （r_s = 0.438 and 0.248， respectively； P < 0.05）， and negatively correlated with the thinnest fibrous cap thickness and minimum lumen area （MLA） （r_s = -0.369 and -0.342， respectively； P < 0.05）. Conclusions Elevated RC is an independent factor associated with intracoronary TCFA in patients with ACS and possesses a certain predictive value for TCFA. It is also correlated with features of plaque vulnerability， such as a thinner fibrous cap， a larger lipid arc， a smaller MLA， and increased macrophage infiltration. RC can serve as a reference for the risk stratification of high-risk coronary plaques in patients with ACS.