Background The vulnerability of non-culprit plaques in patients with coronary heart disease is significantly correlated with the occurrence of future cardiovascular events. However, there has been no breakthrough in the study of non-invasive detection markers of non-culprit plaques at home and abroad.

Objective To analyze the relationship between serum soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) and levels and vulnerability of non-culprit plaques in patients with acute coronary syndrome (ACS).

Methods Optical coherence tomography (OCT) was used to evaluate the plaque vulnerability of ACS patients who received OCT guided therapy in Chinese PLA General Hospital from March 1, 2023 to August 1, 2023. Taking thin-cap fibroatheroma (TCFA) as an indicator of vulnerability, patients were divided into TCFA group and TCFA group according to the presence or absence of TCFA in non-culprit lesions under OCT. Serum of patients was collected before surgery and sera sTREM-1 level was detected by enzyme-linked immunosorbent assay. The baseline data of patients with different plaque vulnerability, the characteristics of non-culprit lesions under contrast imaging and the characteristics of non-culprit lesions under OCT were compared.

Results Among the 47 patients, 39 were male and 8 were female. The mean age was (61.8 ± 11.9) years, and the total serum sTREM-1 level was (M(IQR): 52.5 46.7-60.9) pg/mL. There were 35 cases in the TCFA group and 12 cases in without TCFA group. Sera sTREM-1 level in patients with TCFA was significantly higher than that in patients without TCFA (M(IQR): 57.4 48.6-63.1 pg/mL vs 46.8 41.4-51.6 pg/mL, P=0.006), and the difference was statistically significant. In the patients with TCFA group, the incidence of lips-rich plaque (LRP), cholesterol crystallization and macrophage infiltration, as well as the maximum lipid Angle, average lipid Angle and lipid core length were higher than those in the patients without TCFA group, and the differences between the two groups were statistically significant (all P<0.05). In contrast, the minimum fiber cap thickness of non-culprit lesions in patients with TCFA was significantly lower than that in patients without TCFA (P<0.05). Logistic regression analysis found that high sera sTREM-1 level was an independent association factor for OCT-TCFA in ACS patients with non-culprit lesions (OR=1.198, 95%CI: 1.103-1.300, P<0.001).

Conclusion The results of this study preliminarily suggest that sera sTREM-1 levels in ACS patients are correlated with the vulnerability of non-culprit plaques.