Prehospital prediction of mechanical circulatory support during hospital stay in cardiogenic shock: The FLAG score.

BACKGROUND

Mechanical circulatory support (MCS) is a treatment option in cardiogenic shock (CS) for patients refractory to pharmacological therapy. In a prehospital setting, the ability to predict the need for MCS during hospitalization may influence the choice of the designated hospital.

OBJECTIVES

Development of a prehospital risk score to predict MCS treatment during hospital stay in CS patients.

METHODS

We retrospectively analysed 431 prehospitally treated patients directly admitted to two hospitals of LMU university from 2014 to 2025. Using a logistic regression model that is further refined by a sparse beam algorithm and star ray search, a risk score to predict MCS treatment during hospital stay was developed. 80 % of patients were used for the training and 20 % for the testing cohort. MCS was defined as venoarterial extracorporeal membrane oxygenation (VA-ECMO), Impella CP and Impella 2.5 (Abiomed, Danvers, USA) or left ventricular assist device (LVAD) implantation.

RESULTS

MCS implantation was performed in 34.3 % of patients. The following variables of the prehospital period were included in the model by the algorithm: fibrinolysis, prolonged CPR ≥ 35 min, age ≥ 65 years and female gender (FLAG). Calculated risk for MCS ranged from 16.9 % (-3 points) to 83.1 % (+5 points). An AUROC of 0.707 was achieved in the internal validation cohort.

CONCLUSIONS

The FLAG risk score is a simple, registry-based model to predict MCS treatment during hospital stay in a prehospital setting. These results should be validated and refined in external cohorts.

TRIAL REGISTRATION: WHO International Clinical Trials Registry Platform Number DRKS00015860.