External validation and comparison of the CardShock and IABP-SHOCK II risk scores in real-world cardiogenic shock patients

Background: Mortality from cardiogenic shock remains high and early recognition and risk stratification are mandatory for optimal patient allocation and to guide treatment strategy. The CardShock and the Intra-Aortic Balloon Counterpulsation in Acute Myocardial Infarction Complicated by Cardiogenic Shock (IABP-SHOCK II) risk scores have shown good results in predicting short-term mortality in cardiogenic shock. However, to date, they have not been compared in a large cohort of ischaemic and non-ischaemic real-world cardiogenic shock patients.

Methods: The Red-Shock is a multicentre cohort of non-selected cardiogenic shock patients. We calculated the CardShock and IABP-SHOCK II risk scores in each patient and assessed discrimination and calibration.

Results: We included 696 patients. The main cause of cardiogenic shock was acute coronary syndrome, occurring in 62% of the patients. Compared with acute coronary syndrome patients, non-acute coronary syndrome patients were younger and had a lower proportion of risk factors but higher rates of renal insufficiency; intra-aortic balloon pump was also less frequently used (31% vs 56%). In contrast, non-acute coronary syndrome patients were more often treated with mechanical circulatory support devices (11% vs 3%, p<0.001 for both). Both risk scores were good predictors of in-hospital mortality in acute coronary syndrome patients and had similar areas under the receiver-operating characteristic curve (area under the curve: 0.742 for the CardShock vs 0.752 for IABP-SHOCK II, p=0.65). Their discrimination performance was only modest when applied to non-acute coronary syndrome patients (0.648 vs 0.619, respectively, p=0.31). Calibration was acceptable for both scores (Hosmer-Lemeshow p=0.22 for the CardShock and 0.68 for IABP-SHOCK II).

Conclusions: In our cohort, both the CardShock and the IABP-SHOCK II risk scores were good predictors of in-hospital mortality in acute coronary syndrome-related cardiogenic shock.