Inflammatory indexes as predictors of major adverse cardiovascular events in acute myocardial infarction: insights from the INFINITY Study

Abstract Introduction The inflammatory response following an Acute Myocardial Infarction (AMI) has been extensively studied in recent years and plays a crucial role in post-infarction outcomes. Inflammation contributes to infarct size expansion, is directly linked to ischemia-reperfusion injury, and can lead to adverse left ventricular remodelling, resulting in a larger infarct size and worse prognosis. Therefore, quantifying inflammation may serve as an important prognostic marker in AMI patients. Objective The INFINITY study (INFlammatIoN amI sTudY) investigates the role of selected inflammatory biomarkers in predicting long-term outcomes after AMI. This sub-study evaluates the prognostic value of five inflammatory indexes: Systemic Immune Inflammation Index (SII), Neutrophil-to-Lymphocyte Ratio (NLR), Lymphocyte-to-Monocyte Ratio (LMR), Platelet-to-Lymphocyte Ratio (PLR), Systemic Inflammation Response Index (SIRI). The study focuses on their association with short-term (in-hospital, M0) and long-term (1-month, M1 and 6-month, M6) Major Adverse Cardiovascular Events (MACEs), including cardiac death, non-fatal MI, unplanned revascularization, development of heart failure, angina or recurrent ACS requiring rehospitalization, and major bleeding. Methods A total of 103 patients with AMI (67 STEMI, 36 NSTEMI) were included in the study. Statistical analysis was performed using Cox proportional hazards models to assess the relationship between inflammatory indexes and clinical endpoints. The models were adjusted for age, sex, comorbidities, infarct size, and treatment strategy to account for potential confounders. Results The inflammatory indices SII, NLR, LMR, PLR, and SIRI showed a significant association with MACEs at 6 months. SII was strongly associated with MACEs both in-hospital (M0: p = 0.013) and at 1 month (M1: p = 0.007). SIRI and NLR demonstrated high predictive value for post-infarction MACEs (M1: p = 0.049, p = 0.020, respectively). LMR appeared to have a protective role, as higher values were associated with a lower risk of MACEs (M0: p = 0.234, M1: p = 0.106, M6: p = 0.236). PLR had moderate diagnostic value (M0: p = 0.080, M1: p = 0.024, M6: p = 0.306) but was influenced by other clinical factors. Cox regression models confirmed that SII and SIRI are independent predictors of MACEs, whereas LMR may act as a protective factor. Conclusions Inflammatory markers SII, NLR, SIRI, LMR, and PLR appear to have prognostic significance in AMI patients. Among them, SII and SIRI demonstrated the strongest association with major adverse cardiovascular events (MACEs) and heart failure development. Conversely, LMR may play a protective role. These inflammatory indexes could contribute to improved risk stratification and personalized post-infarction patient monitoring.Table 1 Figure 1