The Role of the Inflammatory Prognostic Index in Patients with Non-ST Elevation Myocardial Infarction Undergoing Percutaneous Coronary Intervention

Background/Objectives: To evaluate the prognostic role of the inflammatory prognostic index (IPI) value at admission in major adverse cardiovascular and cerebrovascular events (MACCEs) in individuals with non-ST elevation myocardial infarction (NSTEMI) undergoing percutaneous coronary intervention (PCI). Methods: A total of 1142 NSTEMI patients with a mean age of 61.9 ± 12.5 years were included. Admission C-reactive protein level, serum albumin level, and complete blood counts of participants were collected from hospital records. The IPI was calculated based on the following formula: C-reactive protein/albumin ratio (CAR) x neutrophil-to-lymphocyte ratio (NLR). An aggregate index of systemic inflammation (AISI) value was calculated using the ‘‘neutrophil count x monocyte count x platelet/lymphocyte count’’ formula. The study cohort was divided into two groups according to the median IPI value. Results: Patients with higher IPI values were statistically more likely to suffer from MACCEs within one year (p < 0.001), thus the admission IPI value was found to be associated with future development of MACCEs. Furthermore, it had sufficient discrimination power (AUC = 0.70) and predictive accuracy in identifying MACCEs compared to other inflammatory parameters such as the CAR (AUC = 0.64), the NLR (AUC = 0.64), and the AISI (AUC = 0.59). Adding the IPI to the baseline multivariable logistic regression model significantly improved the model’s discrimination and net clinical benefit effect for identifying patients who would suffer from MACCEs, with a C-index of 0.84 (95% CI: 0.82–0.86) and explanatory power of 23.2% (R2 = 0.232, DeLong test p = 0.001). High-risk patients with an IPI value greater than 2.43 had significantly more adverse events (p < 0.001). Conclusions: The IPI may be a promising inflammatory index for use in clinical practice to determine the risk prediction of MACCEs in NSTEMI patients undergoing PCI.