Prognostic Performance of the IABP-SHOCK II Risk Score Among Cardiogenic Shock Subtypes in the Critical Care Cardiology Trials Network Registry

Risk stratification has potential to guide triage and decision-making in cardiogenic shock (CS). We assessed the prognostic performance of the IABP-SHOCK II score, derived in Europe for acute myocardial infarct-related CS (AMI-CS), in a contemporary North American cohort, including different CS phenotypes. The Critical Care Cardiology Trials Network (CCCTN) coordinated by the TIMI Study Group is a multicenter network of cardiac intensive care units (CICU). Participating centers annually contribute ≥2 months of consecutive medical CICU admissions. The IABP-SHOCK II risk score includes age >73 years, prior stroke, admission glucose >191 mg/dl, creatinine >1.5 mg/dl, lactate >5 mmol/l, and post-PCI TIMI flow grade <3. We assessed the risk score across various CS etiologies. Of 17,852 medical CICU admissions 5,340 patients across 35 sites were admitted with CS. In patients with AMI-CS (n=912), the IABP-SHOCK II score predicted a >3-fold gradient in in-hospital mortality (low risk = 26.5%, intermediate risk =52.2%, high risk = 77.5%, p<0.0001; c-statistic=0.67; Hosmer-Lemeshow p=0.79). The score showed a similar gradient of in-hospital mortality in patients with non-AMI-related CS (n=2,517, p<0.0001) and mixed shock (n=923, p<0.001), as well as in left ventricular (<0.0001), right ventricular (p = 0.0163) or biventricular (<0.0001) CS. The correlation between the IABP-SHOCK II score and SOFA was moderate (r2=0.17) and the IABP-SHOCK II score revealed a significant risk gradient within each SCAI Stage. In an unselected international multicenter registry of patients admitted with CS, the IABP- SHOCK II score only moderately predicted in-hospital mortality in a broad population of CS regardless of etiology or irrespective of right, left, or bi-ventricular involvement.