Inflammatory Indices in Patients with Myocardial Infarction Complicated by Cardiogenic Shock, and Their Interconnections with SCAI Stages and Patients’ Survival: A Retrospective Study

<b>Background:</b> Myocardial infarction complicated by cardiogenic shock (MI-CS) remains a critical condition with high mortality rates, despite advances in treatment. Systemic inflammation plays a significant role in MI-CS progression; however, its dynamics across different stages of the Society for Cardiovascular Angiography and Interventions (SCAI) classification remain poorly understood. This study aimed to evaluate indices of systemic inflammation-neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), systemic immune-inflammation index (SII), systemic inflammation response index (SIRI), and aggregate index of systemic inflammation (AISI)-in MI-CS patients, correlating them with SCAI stages and survival outcomes. <b>Methods:</b> A single-center retrospective study included 132 patients with MI-CS, categorized into SCAI stages A-E. All patients were assessed for demographic, clinical, and laboratory data, procedural and treatment characteristics, MI timing, and outcomes. Complete blood count test data were used to calculate inflammatory indices and evaluate types of immune reactions. <b>Results:</b> PLR, SII, and AISI peaked at SCAI stage C and declined significantly at stage E, suggesting suppressed inflammation in advanced shock. SIRI emerged as a key prognostic marker for stage C patients, with elevated levels associated with larger infarct size, higher heart rate, and predominant innate immune activation. Patients with SIRI ≥ 3.34 had significantly lower two-year survival (log-rank test, <i>p</i> = 0.006). <b>Conclusions:</b> Inflammation indices, particularly SIRI, provide valuable prognostic insights in MI-CS, reflecting disease severity and heterogeneity of immune response. The decline in inflammatory indices at SCAI stage E may indicate immune suppression in extreme MI-CS, underscoring the need for personalized therapeutic strategies.