Objective To investigate the relationship between the gut microbiota metabolitestrimethylamine N-oxide (TMAO) and bile acids (BA) and neutrophil-related factorsinterleukin-6 (IL-6), reactive oxygen species (ROS) and matrix metalloproteinase-9 (MMP-9) and arterial plaque characteristics and postoperative cardiac function in patients with acute myocardial infarction (AMI).

Methods A total of 108 AMI patients admitted between September 2020 and December 2022 were retrospectively enrolled. All patients were detected by carotid Doppler ultrasonography. According to the thickness of carotid intima-media, the patients were divided into the plaque group (78 cases) and non-plaque group (30 cases). According to the plaque morphology and echo characteristics, the plaque group was subdivided into the stable plaque group (28 cases) and vulnerable plaque group (50 cases). The clinical data of patients, postoperative cardiac function indicators, venous blood and death situations were collected. The levels of postoperative cardiac function indicators of patients were compared. The serum levels of TMAO, BA, IL-6, ROS and MMP-9 of patients were analyzed by enzyme-linked immunosorbent assay. Pearson was used to analyze the correlation between the levels of TMAO, BA, IL-6, ROS and MMP-9 of patients and levels of cardiac function indicators. The predictive value of TMAO, BA, IL-6, ROS and MMP-9 levels for the occurrence of vulnerable carotid plaques was evaluated using the receiver operating characteristic (ROC) curve. The survival curve was plotted using the Kaplan-Meier method, and the survival analysis was conducted.

Results The LVEF level in the non-plaque group was higher than in plaque group, while the levels of LVEDD and LVESD level in the non-plaque group was lower than in plaque group (P ＜ 0.01). Within the plaque group, the LVEF level in the stable plaque group was higher than in vulnerable plaque group (P ＜ 0.01), whereas the levels of LVEDD and LVESD in the stable plaque group was lower than in vulnerable plaque group (P ＜ 0.01). The serum levels of TMAO, BA, IL-6, ROSand MMP-9 in the non-plaque group were lower than those in plaque group (P ＜ 0.01), and these in the stable plaque group were lower than in vulnerable plaque group (P ＜ 0.01). The results of Pearson correlation analysis revealed that the serum levels of TMAO, BA, IL-6, ROS and MMP-9 were negatively correlated with LVEF (P ＜ 0.01), and positively correlated with LVEDD and LVESD (P ＜ 0.01) in AMI patients after treatment. The results of ROC curve analysis showed that the areas under the curve (AUC) for TMAO, BA, IL-6, ROS, and MMP-9 in predicting carotid vulnerable plaque formation were 1.000, 1.000, 1.000, 0.905 and 0.997, respectively (P ＜ 0.01). The survival analysis demonstrated that the survival rate in the non-plaque group was higher than in plaque group, and which in the stable plaque group was higher than in vulnerable plaque group (P ＜ 0.05).

Conclusions The levels of gut microbiota metabolites and neutrophil-related factors have a high predictive value for the formation of arterial vulnerable plaques in patients with acute myocardial infarction, and are negatively correlated with the postoperative recovery level of cardiac function.