New Algorithm Predicts Brain Injury Risk After Cardiac Arrest

Results from the RAPID-MIRACLE trial have demonstrated, for the first time, that the widely used MIRACLE2 risk score can be accurately applied by paramedics outside of a hospital setting to predict brain injury following a cardiac arrest. This advancement could significantly impact immediate patient care and resource allocation.

The Challenge of Out-of-Hospital Cardiac Arrest

Out-of-hospital cardiac arrest (OHCA) carries a high mortality risk, with survival rates below 10%. Even when successful resuscitation is achieved – known as return of spontaneous circulation (ROSC) – determining the extent of brain injury remains a critical challenge for clinicians. Current guidelines recommend transferring OHCA patients to specialist cardiac centers, but the majority are initially taken to local emergency departments.

Introducing the MIRACLE2 Score and Pre-MIRACLE2

The MIRACLE2 score, developed by Dr. Nilesh Pareek, Adjunct Senior Lecturer and Consultant Interventional Cardiologist at King’s College London, accurately predicts the extent of brain damage 30 days after an OHCA. Previously, it was only used within a hospital environment. The RAPID-MIRACLE trial investigated whether the score could be calculated immediately after ROSC in the community.

Researchers tested two versions of the score: one incorporating a blood test and one without. Even as the blood test version proved highly accurate, practical challenges such as technical failures and time constraints often hindered its use. The version without the blood test, termed Pre-MIRACLE2, maintained a comparable level of accuracy.

Impact on Emergency Care

“While MIRACLE² has supported early in-hospital risk stratification following out-of-hospital cardiac arrest, RAPID-MIRACLE extends this work into the pre-hospital setting, enabling paramedics to assess risk earlier in a patient’s care pathway,” explains Dr. Pareek. “By validating the model in the field, we have taken an important step towards integrating earlier risk assessment into routine emergency care.”

The MIRACLE2 App and Future Implementation

The MIRACLE2 app, led by Dr. Pareek and developed by Ensono Digital, has been updated to include the newly validated pre-hospital model. The app utilizes the MIRACLE2 algorithm, allowing clinicians to quickly and accurately calculate the score by inputting patient data such as age, initial heart rhythm, and other relevant markers.

The research team is currently discussing potential service evaluations with emergency medical services to explore the implementation of the updated tool in routine practice.

Study Details

The research findings were presented at the CRT 2026 conference in Washington, D.C., and the full study was published in European Heart Journal: Acute Cardiovascular Care.

The prospective validation of the MIRACLE2 score, conducted in the GLOBAL-MIRACLE registry, involved 770 patients from 11 centers across 5 countries between January 1, 2022, and May 31, 2023. The study found the MIRACLE2 score had an area under the curve of 0.861 (95% CI, 0.835-0.887) for predicting poor neurological outcome at hospital discharge.