Systemic immune-inflammation index as a novel predictor of major adverse cardiovascular events in patients undergoing percutaneous coronary intervention: a meta-analysis of cohort studies

The Systemic Immune-Inflammation Index (SII), a novel marker of inflammation based on neutrophil, platelet, and lymphocyte counts, has demonstrated potential prognostic value in patients undergoing percutaneous coronary intervention (PCI). Our aim was to assess the correlation between the SII and major adverse cardiovascular events following percutaneous coronary intervention. We searched PubMed, Web of Science, Embase, and The Cochrane Library from inception to November 20, 2023, for cohort studies investigating the association between SII and the occurrence of MACEs after PCI. Statistical analysis was performed using Revman 5.3, with risk ratios (RRs) and 95