Abstract WP248: Developing and Validating Post-Treatment HERMES Score to Predict Outcome From Anterior Circulation Large Vessel Occlusion Stroke: A Meta-Analysis of Individual Data From 7 Randomized Clinical Trials

Abstract

Introduction: Clinicians need simple and highly predictive prognostic scores to assist practical decision-making and family discussion. We aimed to develop and validate a simple prediction score applied at 24 hours to assist prognostication in patients with anterior circulation ischemic stroke due to large vessel occlusion. Methods: Using the HERMES collaboration dataset (n = 1764), patients in the endovascular therapy (EVT) arm were divided randomly into a derivation cohort (n = 430) and a validation cohort (n = 441). From a set of candidate predictors, forward selection using c-statistics was employed to select a model which was both parsimonious and highly predictive for modified Rankin Scale (mRS) ≤2 at 90 days. The score was validated in both the EVT validation cohort and in the control arm (n = 893) for mRS ≤2 and ≤3. Results: In the derivation cohort, two significant predictors of mRS ≤2 (National Institutes of Health Stroke Scale [NIHSS] score at 24 h and age [β-coefficient 0.34 and 0.06]) were selected. Incorporating other variables did not much improve model performance. Among models with different weights, we derived the HERMES score: age (years)/10 + NIHSS score at 24 h, based on model performance and simplicity. The HERMES score was highly predictive for mRS ≤2 in the derivation cohort, validation cohort-EVT, and control arm (c-statistics 0.907, 0.914, and 0.909, respectively). Evaluation of the score against mRS ≤3 as an alternative outcome yielded similar results (c-statistics 0.911, 0.903, and 0.885). Among 435 subjects (24.7%) with HERMES score ≥25, the observed probability was 3.1-3.4% for mRS ≤2 and 9.4-16.7% for mRS ≤3 in the derivation cohort, validation cohort-EVT, and control arm (Figure). Conclusions: The HERMES score is a simple validated score to predict outcomes in patients with anterior circulation large vessel occlusion ischemic stroke regardless of intervention. HERMES score should be helpful in prognostic discussion with families on day two.