Objective/background: We compared the discrimination performance of the MIRACLE2 score, downtime and current randomized control trial (RCT) recruitment criteria in predicting poor neurological outcome after out-of-hospital cardiac arrest (OHCA).
Methods: We used the European Cardiac Arrest Registry (EUCAR), a retrospective cohort from 6 centres (May 2012-September 2022). The primary outcome was poor neurological outcome on hospital discharge (Cerebral Performance Category 3-5).
Results: 1259 patients (total downtime 25, IQR 15-36 minutes) were included in the study. Poor outcome occurred in 41.8% with downtime <30 minutes, and in 79.3% for those >30 minutes. In a multivariable logistic regression analysis, MIRACLE2 had a stronger association with outcome (OR 2.23 [CI 1.98-2.51] p<0.0001) than zero-flow (OR 1.07 [CI 1.01-1.13], p=0.013), low-flow (OR 1.04 [CI 0.99-1.09], p=0.054) and total downtime (OR 0.99 [CI 0.95-1.03], p=0.52). MIRACLE2 had substantially superior discrimination for the primary end-point [AUC 0.877 (95% CI 0.854 to 0.897)] than zero-flow [AUC 0.610 (95% CI 0.577-0.642)], low-flow [AUC 0.725 (95% CI 0.695-0.754)] and total downtime [AUC 0.732 (95% CI 0.701-0.760)]. For those modelled for exclusion from study recruitment, the positive predictive value of MIRACLE2 ≥5 for poor outcome was significantly higher (0.92) than CULPRIT-SHOCK (0.80), EUROSHOCK (0.74) and ECLS-SHOCK criteria (0.81) (p<0.001).
Conclusions: The MIRACLE2 score has superior prediction of outcome after OHCA than downtime and higher discrimination of poor outcome than current RCT recruitment criteria. The potential for the MIRACLE2 score to improve selection of OHCA patients should be evaluated formally in future RCTs.
