Higher remnant cholesterol to lymphocyte ratio is associated with vulnerable plaque features in acute coronary syndrome.

Background: Remnant cholesterol to lymphocyte ratio (RCLR) integrates atherogenic lipid metabolism and systemic inflammation, potentially reflecting plaque vulnerability in acute coronary syndrome (ACS). However, its association with intracoronary imaging features remains unclear. This study aimed to investigate the relationship between RCLR and culprit plaque characteristics using optical coherence tomography (OCT). Methods: This retrospective study analyzed 450 ACS inpatients (2021-2024), with 201 included after rigorous selection. The patients were classified into three groups based on the remnant cholesterol to lymphocyte ratio [RCLR; remnant cholesterol (RC = TC-HDL-C-LDL-C) divided by lymphocyte percentage], using tertiles: Group T1 (RCLR ≤ 3.03, Results: OCT imaging analysis revealed significant differences in qualitative features among various RCLR groups, including plaque rupture, lipid plaque, thin-cap fibroatheroma (TCFA), and superficial calcification (all Conclusion: In ACS patients, a higher RCLR was associated with high-risk plaque characteristics detected by OCT, such as lipid-rich plaques, TCFA, and plaque rupture, and the highest RCLR tertile remained associated with these features after multivariable adjustment. RCLR exhibits a certain predictive ability for these vulnerable plaque features. Higher RCLR tertiles were associated with a greater prevalence of vulnerable plaque features, suggesting that RCLR may serve as a composite lipid-inflammatory marker associated with coronary plaque vulnerability, although its signal partly overlaps with systemic inflammatory-cell parameters.