Association of Systemic Immune-Inflammation Index with in-hospital mortality of cardiogenic shock patients supported with extracorporeal membrane oxygenation.

Purpose: The systemic immune-inflammation index (SII) is a useful predictor in cardiovascular diseases. The purpose of this study was to investigate the association of SII with in-hospital mortality in patients with cardiogenic shock (CS) supported with extracorporeal membrane oxygenation (ECMO).

Patients and methods: A total of 126 CS patients received ECMO implantation between January 2020 and December 2023. SII was calculated as follows: SII = neutrophil count × platelet count / lymphocyte count at admission. Participants were divided into high or low SII group based on the cut-off value of SII. In-hospital mortality was compared between the groups.

Results: The optimal SII cut-off value for predicting in-hospital mortality in CS patients supported with ECMO was 1735.9 (AUC 0.68, p = 0.001). In-hospital mortality was significantly higher in the high SII group compared to the low SII group (59.09% vs. 21.67%, p <0.001). The univariate and multivariate logistic regression analyses had shown that SII and left ventricular ejection fraction (LVEF) were identified as independent predictors of in-hospital mortality in CS patients supported with ECMO (OR: 1.001, 95% CI: 1.000-1.002, p = 0.007 and OR: 0.881, 95% CI: 0.803-0.966, p = 0.007, respectively). SII combined with LVEF offered a superior prognostic capability compared to SII alone (AUC 0.707, v.s. AUC 0.68).

Conclusion: We demonstrated that elevated admission SII was independently associated with in-hospital mortality in CS patients supported with ECMO. These findings highlight the potential role of SII as an indicator of mortality risk in this population.