Abstract 320: Gray-white Matter Ratio Under 1.12 Could Predict Poor Neurological Outcomes, Even When Measured Within Two Hours After Return Of Spontaneous Circulation

Abstract

Introduction: Literature on neuroprognostication suggests that gray-white matter ratio (GWR) measured from head computed tomography (CT) within two hours after return of spontaneous circulation (ROSC) can’t adequately predict neurological outcomes in out-of-hospital cardiac arrest (OHCA) patients. However, severe cerebral edema may predict poor outcomes within two hours after ROSC. Hypothesis: We evaluated if GWR measurements obtained early after OHCA (≤ 2 hours) indicated poor neurological outcomes in patients with severe cerebral edema. Methods: We conducted a multicenter, retrospective cohort study using data from five hospitals collected between 2007 and 2019 in Japan. Inclusion criteria: adult comatose OHCA survivors with head CT within two hours after ROSC. Exclusion criteria was trauma, stroke, or pre-existing neurological disorders. Primary outcome was poor neurological outcome, defined as Cerebral Performance Category (CPC) score ≥ 3 at one month after admission. GWR was measured at the levels of the basal ganglia (BG), corpus callosum (CC), and posterior internal capsule (PIC). The prognostic value of GWR for predicting poor outcome was assessed using a receiver operating characteristic (ROC) curve analysis, area under the curve (AUC) with sensitivity/specificity. Results: A total of 377 patients were included. Of those, 281 (74.6%) exhibited poor neurological outcome at one month after admission. GWR values did not alter by the time of obtaining head CT: 1.22 (0-30 min: n=194); 1.22 (31-60 min: n=127); 1.22 (61-120 min: n=56). Using a cut-off GWR value of <1.2, ROC analysis demonstrated AUC for GWR-BG (0.69, 95% CI 0.65-0.73), GWR-CC (0.77, 95% CI 0.69-0.76), and GWR-PIC (0.76, 95% CI 0.72-0.79) with sensitivities/specificities of 45.5%/92.7%, 47.6%/97.9%, 55.8%/96.8%, and 46.2%/97.9%, respectively for poor outcomes. However, GWR values <1.12 demonstrated 100% specificity for poor outcomes: GWR-BG (AUC 0.56, sensitivity/specificity 13.5%/100%), GWR-CC (AUC 0.56, sensitivity/specificity 13.5%/100%), and GWR-PIC (AUC 0.59, sensitivity/specificity 19.5%/100%). Conclusion: GWR (<1.12) obtained even within two hours after ROSC could be used as a threshold for poor neurological outcome in OHCA patients.