Predictive value of the APACHE II score in cardiogenic shock patients treated with a percutaneous left ventricular assist device

Background: The APACHE II score assesses patient prognosis in intensive care units. Different disease entities are predictable by using a specific factor called Diagnostic Category Weight (DCW). We aimed to validate the prognostic value of the APACHE II score in patients treated with a percutaneous left ventricular assist device because of refractory cardiogenic shock (CS). Methods: From the Dresden Impella Registry , we analyzed 180 patients receiving an Impella CP (R). The main outcome was the observed intrahospital mortality ((S) over cap (t(hosp))), which was compared to the predicted mortality estimated by the APACHE II score. Results: The APACHE II score, which was 33.5 +/- 0.6, significantly overestimated intrahospital mortality ((S) over cap (t(hosp)) 54.4 +/- 3.7% vs. APACHE II 74.6 +/- 1.6%; p < 0.001). Nevertheless, the APACHE II score showed an acceptable accuracy to predict intrahospital mortality (ROC AUC 0.70; 95% CI 0.62-0.78). Thus, we adapted the formula for calculation of predicted mortality by adjusting DCW. The total registr y cohort was randomly divided into derivation group for calculation of adjusted DCW and validation group for testing. Intrahospital mortalit y was much more precisely predicted using the adjusted DCW compared to the conventional DCW (difference of predicted and observed mortality: -4.7 +/- 2.4% vs. -23.2 +/- 2.3%; p < 0.001). The new calculated DCW was-1.183 for the total cohort. Conclusion: The APACH E II score has an acceptable accuracy for the prediction of intrahospital mortality but overestimates its total amount in CS patients. Adjustment of the DCW can lead to a much more precise prediction of prognosis.