Abstract 13407: Validation of the MIRACLE2 Score for Prognostication After Out of Hospital Cardiac Arrest

Abstract

Background: Early prediction of long-term outcomes after out-of-hospital cardiac arrest (OOHCA) remains a diagnostic challenge. MIRACLE2 is a points-based risk score that has been derived as a simple tool to aid clinicians in prognosticating those at high risk of poor neurological outcomes. To date, the score has been validated in two independent cohorts in the MIRACLE2 study. The aim of this study was to validate the MIRACLE2 score in a further independent cohort, with the primary outcome poor neurological outcome at 6 months (Cerebral Performance Category (CPC) 3-5). Methods: We retrospectively identified all patients treated at the Bristol Royal Infirmary from January 2019 to July 2020 with a primary or secondary ICD-10 diagnosis code for cardiac arrest. Patients were screened against the inclusion and exclusion criteria used in the MIRACLE2 study and the data required to calculate the MIRACLE2 and CPC scores were extracted from medical records. Results: 198 patients met the OOHCA inclusion criteria and were included for analysis. Multivariable logistical regression confirmed 6 out of the 7 MIRACLE2 components as independent predictors of poor neurological outcome at 6 months: age category (60-80 years, OR 6.4, p=0.005; >80 years, OR 148.1, p<0.001), initial non-shockable rhythm (OR 36.9, p<0.001), non-reactivity of pupils (OR 13.7, p=0.002), low pH <7.20 (OR 5.1, p=0.014), adrenaline administration (OR 4.1, p=0.024), changing intra-arrest rhythms (OR 3.4, p=0.048). The MIRACLE2 score had an area under the curve of 0.89. The risk of poor neurological outcome in this cohort, across the previously described MIRACLE2 score risk groups (low <=2, intermediate 3-4, and high >=5), was comparable to that in the MIRACLE2 study (low: 15% vs. 6%; intermediate: 54% vs. 55%; and high: 93% vs. 92%, respectively). Conclusion: The MIRACLE2 score has been externally validated in an independent cohort as an accurate predictor of poor neurological outcome following OOHCA.