In-Hospital and Long-Term Clinical Outcomes in Patients With Acute Myocardial Infarction Categorized as SCAI Shock Stage B.

Background: The mortality rate for acute myocardial infarction (AMI) complicated with cardiogenic shock (CS) remains high despite advances in mechanical circulatory support (MCS). The Society for Cardiovascular Angiography and Interventions (SCAI) has proposed a 5-stage classification of CS, and in this study we compared the clinical outcomes of AMI patients with SCAI shock stage A with those in stage B. Methods and Results: We retrospectively analyzed 257 AMI patients, classified into modified stage A (n=180) and modified stage B (n=77) groups. The primary endpoint was in-hospital adverse events, defined as a composite of in-hospital death, initiation of MCS, and mechanical complications. The secondary endpoint was long-term major adverse cardiovascular events (MACE), including all-cause death, re-admission for heart failure, or non-fatal myocardial infarction. The median follow-up duration was 786 days. Compared with modified stage A, modified stage B group had a significantly lower left ventricular ejection fraction (44.6% vs. 54.4%, P<0.001). In-hospital adverse events were comparable between the groups (P=0.128). Kaplan-Meier analysis showed a higher incidence of MACE in modified stage B (P=0.029); however, multivariate analyses revealed no significant association between modified stage B and either in-hospital adverse events or long-term MACE. Conclusions: As compared to SCAI shock modified stage A, modified stage B was not independently associated with in-hospital and long-term clinical outcomes after controlling confounding factors.