Systemic Immune–Inflammation Index Predicting Acute Cardiovascular Outcomes

Background/Objectives: Acute coronary syndrome (ACS) and acute decompensated heart failure (ADHF) are associated with substantial short-term morbidity and mortality. The systemic immune–inflammation index (SII) reflects inflammatory and thrombotic activity, but its prognostic value beyond conventional biomarkers and clinical risk scores remains uncertain. This study aimed to evaluate the prognostic value of SII for short-term major adverse cardiovascular events (MACEs) and assess its incremental value beyond established biomarkers and clinical risk scores.