TTM Score More Accurately Predicts Neurological Outcomes and Mortality After Cardiac Arrest, Study Finds

While out-of-hospital cardiac arrest remains a major global mortality challenge requiring prompt post-resuscitation evaluation, comparative evidence evaluating post-arrest scoring tools specifically in cardiac-origin cases has remained scarce. Addressing this gap, Natthaka Sathaporn and Bodin Khwannimit from the Division of Critical Care Medicine at Prince of Songkla University in Thailand evaluated the predictive accuracy of the MIRACLE2, Cardiac Arrest Hospital Prognosis (CAHP), and TTM scores against general ICU models—including Acute Physiology and Chronic Health Evaluation II (APACHE II), Simplified Acute Physiology Score II (SAPS II), and SAPS-3—for forecasting neurological recovery and hospital mortality following cardiac resuscitation.

Therefore, the retrospective study evaluated 158 adult patients admitted to a Thai academic intensive care unit following resuscitated cardiac-origin out-of-hospital cardiac arrest. Researchers compared six risk scores to assess their accuracy in predicting poor discharge neurological recovery and hospital mortality.

Key Clinical Findings of the Study Include:

• Overall Mortality and Neurological Rates Findings indicated an overall hospital mortality of 53.2%, with 73.4% of post-arrest patients suffering unfavorable neurological status at discharge.
• TTM Score Predictive Superiority: Data demonstrated that the TTM score achieved the highest discriminative performance for poor neurological status (AUROC: 0.899) and mortality (AUROC: 0.854), significantly outperforming MIRACLE2 (p = 0.005), APACHE II (p < 0.001), SAPS II (p < 0.001), and SAPS-3 (p < 0.001).
• High-Specificity Thresholds Analysis established that thresholds of TTM ≥16 (sensitivity 74.1%), MIRACLE2 ≥5 (sensitivity 69.0%), and CAHP ≥200 (sensitivity 66.4%) each provided identical high specificity of 90.5% for poor neurological recovery.
• Divergent Clinical Predictors: Investigation revealed that patients with good neurological recovery were younger (56.5 vs 61 years; p = 0.013), presented more often with shockable rhythms (76.2% vs 29.3%; p < 0.001), and had shorter no-flow times (4 vs 10 minutes; p < 0.001) and lower lactate levels (5.4 vs 8.9 mmol/L; p < 0.001).
• Extreme Risk Stratification: Results showed no poor outcomes for TTM <5, MIRACLE2 <2, or CAHP <120, whereas TTM ≥19, MIRACLE2 ≥7, and CAHP ≥290 each predicted 100% poor neurological status.

The results suggest that while all evaluated scores effectively predict post-arrest outcomes with AUROC values exceeding 0.80, the TTM score provides superior accuracy, reaching an AUROC of 0.899 for poor neurological status and 0.854 for hospital mortality. Furthermore, applying cutoff thresholds like TTM ≥16 or MIRACLE2 ≥5 yields high specificity above 90% for identifying severe neurological impairment.

Thus, the study concludes clinicians managing post-cardiac arrest care may consider integrating the TTM risk score into routine evaluations to enhance prognostication accuracy while balancing its clinical granularity against simpler tools like MIRACLE2 in time-sensitive emergency settings.

Although this single-center retrospective study was limited by institutional practice patterns and short-term evaluations restricted to hospital discharge, prospective multicenter studies assessing long-term functional recovery would be valuable to confirm these findings across diverse settings.

Reference

Sathaporn N, Khwannimit B. Comparison of MIRACLE2, Cardiac Arrest Hospital Prognosis, Target Temperature Management, and General Severity Scores for Predicting Poor Neurological Outcomes and Mortality after Out-of-hospital Cardiac Arrest. Indian Journal of Critical Care Medicine. 2026;30(9):773–778.