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. BackgroundA relevant proportion of patients presenting via emergency medical services (EMS) develops cardiogenic shock (CS): Depending on the study, between 6.5 % and 11.3 % of patients with acute myocardial infarction (AMI) suffered CS.According to the SEMICA-2 study, 1.6 % of patients hospitalized for acute heart failure developed CS. [1][2]2][3] If medical treatment for CS is insufficient, mechanical circulatory support (MCS) might be considered.However, the use of MCS for CS treatment is arguable: The ECLS shock trial did not demonstrate a benefit for