Association Between Illness Severity Scores and Quantitatively Measured Brain Injury in Cardiac Arrest Survivors

Introduction: This study explored how illness severity scores correspond to hypoxic-ischemic brain injury (HIBI) after cardiac arrest. Methods: This study included cardiac arrest survivors with sufficient data to calculate the Pittsburgh Cardiac Arrest Category (PCAC) and revised post-cardiac arrest syndrome for therapeutic hypothermia (rCAST) scores who underwent brain magnetic resonance imaging and cerebrospinal fluid neuron-specific enolase (CSF-NSE) measurement within 6 h after return of spontaneous circulation. The primary outcome was the association of PCAC and rCAST with quantitative brain injury markers assessed using whole brain mean apparent diffusion coefficient (mean ADC), low ADC volume fractions (PV600, 650, and 700), and CSF-NSE. Results: In total, 81 patients were included. PCAC was not significantly associated with CSF-NSE, mean ADC, or PVs. The rCAST score was significantly associated with higher CSF-NSE, lower mean ADC, and higher PV700. The neurologic sub-score of PCAC was independently associated with all evaluated brain injury markers, whereas the systemic sub-score was not. Of the individual rCAST components, anoxic time was independently associated with CSF-NSE, whereas no other single component was associated with these markers. Conclusions: rCAST was significantly associated with degree of HIBI, whereas PCAC was not. The neurologic sub-score of PCAC showed independent associations with HIBI.