Cardiogenic shock (CS) remains a leading cause of death among patients with acute myocardial infarction.

Although acute myocardial infarction has historically been the leading cause of cardiogenic shock, decompensated heart failure is increasing in prevalence and dominates recent registries.

Cardiogenic shock is a dynamic and hemodynamically heterogeneous condition, with diagnosis based primarily on clinical evaluation with few standard criteria. This heterogeneity has made study design and data interpretation difficult.

In the absence of evidence-based standards, current practices in the treatment of CS are driven mainly by clinician preference and experience; thus, a common language and principles is needed to facilitate the acquisition of high-quality data.

The Society for Cardiovascular Angiography and Interventions (SCAI) has devised a system for classifying and staging the severity of cardiogenic shock based on clinical variables; validation studies have demonstrated a convincing correlation between the SCAI shock stages and risk of mortality.