Classification of 90-day mortality risk among patients with cardiogenic shock requiring advanced mechanical circulatory support

Abstract Background The SCAI shock classification aims to provide a simple and practical stratification of the severity of patients with cardiogenic shock (CS) and to immediately offer them crucial treatments such as mechanical circulatory support (MCS). Additionally, the IABP shock II risk score is designed to predict 30-day mortality in patients with CS following acute coronary syndrome (ACS), and the SAVE score can also predict in-hospital mortality for patients after veno-arterial extracorporeal membrane oxygenation (V-A ECMO) insertion due to refractory CS. However, previous studies on SCAI staging in patients with MCS have been inconsistent, and the association with prognosis remains unclear. Purpose The aim of this study is to investigate the correlation between the SCAI shock stage and prognosis in ACS patients requiring advanced MCS, and to compare it with other prognostic scores. Methods From January 2012 to July 2023, 137 ACS patients with advanced MCS (excluding IABP) were evaluated. Upon ICU admission, patients were categorized into SCAI stages B to E. The IABP shock II score and the SAVE score were also calculated to serve as prognostic tools. The type of MCS was categorized as Impella, VA-ECMO with IABP, and ECPELLA (VA-ECMO with Impella). We compared the 90-day survival rates with the SCAI shock stage and other prognostic tools. Result The distribution for SCAI classifications stage B to E was 13 (10%), 38 (28%), 21 (15%), and 65 (47%), respectively. There were no significant differences among the groups regarding age, gender, comorbidities, the ratio of ST-elevation myocardial infarction, door-to-balloon time, and onset-to-reperfusion time. In SCAI Stage E, a significantly higher proportion of patients (86%) underwent extracorporeal cardiopulmonary resuscitation, exhibiting elevated lactate and peak CK-MB levels, along with higher IABP Shock II and lower SAVE scores, compared to other stages. A Kaplan-Meier analysis of 90-day mortality, based on the SCAI, the IABP Shock II, the SAVE categories, and the type of MCS, demonstrated that outcomes deteriorated as the stage advanced across all classifications. In the univariate Cox regression analysis for 90-day mortality, significant differences in outcomes were observed across the four classifications. However, in the multivariate Cox regression analysis that incorporated all four classifications, only the type of MCS (Impella vs. ECMO with IABP; hazard ratio [HR] 0.36; 95% confidence interval [CI], 0.16 - 0.78, p = 0.012) and the SCAI classification (stage E vs. stage C; HR 3.03; 95% CI, 1.51 - 6.08, p = 0.002) demonstrated a significant association with 90-day mortality. Conclusion The SCAI shock stage upon ICU admission suggests the potential for convenient prediction of mid-term outcomes in ACS patients who received advanced MCS.