Examining the relationship between monocytes and monocyte-derived ratios in post-percutaneous coronary intervention patients and their impact on coronary artery disease progression

Background: Inflammation plays a key role in the progression and instability of coronary atherosclerosis. Monocytes and their ratios with eosinophils and lymphocytes serve as valuable markers for assessing inflammation. We explored blood monocyte levels and their related ratios in patients undergoing percutaneous coronary intervention (PCI) for in-stent restenosis (ISR) or significant de novo lesions (DNL). Methods and results: A total of 3912 PCI procedures were identified from a single-center retrospective registry (2013−2022) and categorized into three groups: single PCI and no subsequent intervention (control group, n = 3342), significant ISR requiring repeat PCI (ISR-PCI group, n = 219), and significant de novo lesions requiring repeat PCI (DNL-PCI group, n = 351). Monocyte counts and monocyte-related ratios were evaluated at the index procedure and follow-up (clinical or repeat PCI procedures). Comorbidities were more prevalent in the ISR-PCI and DNL-PCI groups than those in the control group. In comparison to the control group, both ISR-PCI (15.6 ± 26.7 vs. 24.4 ± 37.8, P < 0.001) and DNL-PCI groups (16.2 ± 28.5 vs. 24.4 ± 37.8, P < 0.001) exhibited a significantly lower baseline monocyte-to-eosinophil ratio. In the adjusted regression models, a lower baseline monocyte-to-eosinophil ratio (P = 0.001) and monocyte-to-lymphocyte ratio (P = 0.04) were associated with DNL, whereas no such association was observed in ISR-PCI cases (P = 0.4 for both ratios). Conclusion: Our findings reinforce the role of inflammatory markers, such as monocytes and monocyte-related ratios, in identifying individuals at risk for the progression of coronary disease post-PCI.