Risk Stratification for Patients in Cardiogenic Shock After Acute Myocardial Infarction

Background Mortality in cardiogenic shock (CS) remains high. Early risk stratification is crucial to make adequate treatment decisions. Objectives This study sought to develop an easy-to-use, readily available risk prediction score for short-term mortality in patients with CS, derived from the IABP-SHOCK II (Intraaortic Balloon Pump in Cardiogenic Shock) trial. Methods The score was developed using a stepwise multivariable regression analysis. Results Six variables emerged as independent predictors for 30-day mortality and were used as score parameters: age >73 years, prior stroke, glucose at admission >10.6 mmol/l (191 mg/dl), creatinine at admission >132.6 μmol/l (1.5 mg/dl), Thrombolysis In Myocardial Infarction flow grade <3 after percutaneous coronary intervention, and arterial blood lactate at admission >5 mmol/l. Either 1 or 2 points were attributed to each variable, leading to a score in 3 risk categories: low (0 to 2), intermediate (3 or 4), and high (5 to 9). The observed 30-day mortality rates were 23.8%, 49.2%, and 76.6%, respectively (p < 0.0001). Validation in the IABP-SHOCK II registry population showed good discrimination with an area under the curve of 0.79. External validation in the CardShock trial population (n = 137) showed short-term mortality rates of 28.0% (score 0 to 2), 42.9% (score 3 to 4), and 77.3% (score 5 to 9; p < 0.001) and an area under the curve of 0.73. Kaplan-Meier analysis revealed a stepwise increase in mortality between the different score categories (0 to 2 vs. 3 to 4: p = 0.04; 0 to 2 vs. 5 to 9: p = 0.008). Conclusions The IABP-SHOCK II risk score can be easily calculated in daily clinical practice and strongly correlated with mortality in patients with infarct-related CS. It may help stratify patient risk for short-term mortality and might, thus, facilitate clinical decision making. (Intraaortic Balloon Pump in Cardiogenic Shock II [IABP-SHOCK II]; NCT00491036)