SCAI Shock Classification in Acute Myocardial Infarction: Insights from the National Cardiogenic Shock Initiative

Objectives: We applied the cardiovascular angiography and interventions (SCAI) shock staging system to patients presenting with acute myocardial infarction and cardiogenic shock (AMI-CS) who were enrolled in the National Cardiogenic Shock Initiative (NCSI).

Background: The SCAI shock staging system provides a framework for evaluation of patients with CS based on clinical and hemodynamic parameters, but has not been validated in patients with AMI-CS managed with a contemporary treatment algorithm that incorporates early use of Impella.

Methods: Consecutive patients enrolled in NCSI were identified, all of whom were managed with invasive hemodynamic guidance and supported with Impella. Patients were retrospectively categorized into appropriate SCAI shock stages, and outcomes were assessed accordingly.

Results: A total of 300 patients were included in the analysis; 182 patients (61%) presented in Stage C shock, 25 (8%) in Stage D, and 93 (31%) in Stage E. Survival to hospital discharge was 76, 76, and 58%, respectively (p = .006). Survival was <20% among patients in Stage E at 24 hr, regardless of baseline stage. There was near perfect agreement in shock staging between two independent clinicians at baseline (kappa = 0.975, 95% CI, 0.95-1.00, p < .001) and at 24 hr (kappa = 0.985, 95% CI, 0.77-1.00, p < .001).

Conclusion: In patients with AMI-CS enrolled in NCSI, SCAI Shock classification was reproducible, and predicted survival when applied at presentation and at 24 hr.