The association of the systemic immune-inflammation index and stent thrombosis in myocardial infarction patients after coronary stent implantation—a retrospectively study

BACKGROUND: A small number of patients can develop stent thrombosis after coronary stent implantation. Diabetes, malignant tumors, anemia, etc. have been identified as risk factors for stent thrombosis. A previous study confirmed that the systemic immune-inflammatory index is associated with venous thrombosis. However, there are no studies investigating the association between the systemic immune-inflammation index and stent thrombosis after coronary stent implantation, and thus, we designed this study. METHODS: A total of 887 myocardial infarction patients admitted to the Wuhan University Hospital from January 2019 to June 2021 were included. All of the patients received coronary stent implantation and were followed up for 1 year by clinic visit. The patients were divided into a stent thrombosis group (n=27) and a control group (n=860) according to whether or not they suffered stent thrombosis. The clinical features of the two groups were observed, and the receiver operator characteristic (ROC) curve was used to analyze the predictive value of the systemic immune-inflammation index for stent thrombosis in patients with myocardial infarction after coronary artery stenting. RESULTS: Compared with the control group, the proportion of stent number ≥4 in the stent thrombosis group was significantly higher (62.96% vs. 38.72%, P=0.011), and the proportion of patients with a systemic immune-inflammation index ≥636 was markedly increased (55.56% vs. 23.26%, P=0.000). The number of stents and the systemic immune-inflammation index were both valuable in predicting stent thrombosis, and the predictive value of the systemic immune-inflammation index was higher, with an area under the curve of 0.736 (95% confidence interval: 0.647–0.824, P=0.000), the best diagnostic value was 636, and the sensitivity and specificity were 0.556 and 0.767. The systemic immune-inflammation index ≥636 and the number of stents ≥4 were independent risk factors for stent thrombosis after coronary stent implantation (P<0.05). Compared with the control group, the incidence of recurrent myocardial infarction was notably increased in the stent thrombosis group (33.33% vs. 3.26%, P=0.000), and mortality was significantly higher in the stent thrombosis group (14.81% vs. 0.93%, P=0.000). CONCLUSIONS: The systemic immune-inflammation index was associated with the development of stent thrombosis in patients with myocardial infarction after coronary stent implantation.