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

Objective To investigate the dynamic changes in systemic immune inflammatory index (SII) during the perioperative period of primary percutaneous coronary intervention (PPCI) and to evaluate its predictive value for in-hospital and out-of hospital outcomes in patients with ST-segment elevation myocardial infarction (STEMI). Methods This retrospective study included 324 consecutive STEMI patients in a cardiac care unit. Blood samples were collected 12h before, 12h after(T1), 24h after, 48h after PPCI, the last time before hospital discharge (T2), and 1 month after hospital discharge. SII was calculated as (neutrophils×platelets)/lymphocytes. Based on whether the primary endpoint occurred, we divided the research sample into two groups, which were the event and the non-event group. Univariable and multi-variable logistic regression analyses were performed to detect the independent risk factors that might influence the occurrence of the primary endpoint. Dynamic curves with 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 the occurrence of in-hospital and out-of hospital course. Kaplan-Meier curves were used to analyze the differences in survival rates at different status of SII inflammation levels; Results High levels of SII were individually related with the occurrence of 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). And patients with high SII levels had lower survival rates than those with lower SII levels. The analysis showed that SII 12h after(T1) and SII 1 month(T1M) had a excellent predictive value 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 dynamic status of SII and the prognosis in STEMI patients. This study found that SII 12h and SII 1 month had an effect on in-hospital and out-of hospital outcomes, respectively. Consequently, we should focus on the dynamic change of SII.