The prognostic value of dynamic changes in SII for the patients with STEMI undergoing PPCI

Background Predicting the prognosis of primary percutaneous coronary intervention(PPCI) in ST-segment elevation myocardial infarction (STEMI) patients in the perioperative period is of great clinical significance. The inflammatory response during the perioperative period is also an important factor. This study aimed to investigate the dynamic changes in the systemic immune inflammatory index (SII) during the perioperative period of PPCI and evaluate its predictive value for in-hospital and out-of-hospital outcomes in patients with STEMI. Methods This retrospective study included 324 consecutive patients with STEMI who were admitted to the cardiac care unit. Blood samples were collected before PPCI, 12 h (T1), 24 h, 48 h after PPCI, the last time before hospital discharge (T2), and 1 month after hospital discharge. The SII was calculated as (neutrophils×platelets)/lymphocytes. Based on whether the primary endpoint occurred, we divided the patients into event and non-event groups. Univariate and multivariate logistic regression analyses were performed to identify independent risk factors that might influence the occurrence of the primary endpoint. Dynamic curves of SII were plotted, and receiver operating characteristic (ROC) curves were drawn for each node to calculate the optimal critical value, sensitivity, and specificity to assess their predictive ability for in-hospital and out-of-hospital courses. Kaplan-Meier curves were used to analyze the differences in survival rates at different SII inflammation levels. Results High levels of SII were individually related to the occurrence of the in-hospital period and long-term outcomes during the post-operative follow-up of STEMI patients (in-hospital SII: T1: OR 1.001,95%CI 1.001–1.001, P < 0.001 ; SII following hospital discharge: T1M: OR 1.008,95%CI 1.006–1.010, P < 0.001 ). Patients with high SII levels had lower survival rates than those with low SII levels. The analysis showed that the SII 12 h after (T1) and SII 1 month (T1M) had excellent predictive values for the occurrence of in-hospital and out-of-hospital outcomes, respectively ( AUC:0.896, P < 0.001; AUC:0.892, P < 0.001 ). Conclusion There is a significant relationship between the dynamic status of SII and prognosis in patients with STEMI. This study found that the 12 h and SII 1 month affected in-hospital and out-of-hospital outcomes, respectively. Consequently, we focused on the dynamic changes in the SII.