Abstract A078: Development of Prognostic Models and Nomograms for Independent Ambulation After Endovascular Thrombectomy in the SELECT2 Trial

Background: While endovascular thrombectomy(EVT)improved outcomes for large ischemic strokes in randomized trials, only one in three EVT patients achieved mRS 0-3. Accurate prognostication for patient selection, counseling, and management is difficult with currently available tools and not readily applicable to clinical practice. Methods: From SELECT2 randomized trial, EVT patients were analyzed. A pre-thrombectomy model using baseline, and a post-thrombectomy model with both baseline and post-procedural variables were developed through backward stepwise regression with relevant clinical and imaging variables to predict mRS 0-3. Discrimination, Hosmer Lameshow goodness of fit, calibration analyzed, 5-fold crossvalidation performed for internal validation and nomograms were developed. Results: Tissue volume with 30 associated with >99% probability of mRS 0-3 for pre-; and scores 28 associated with >99% probability of mRS 0-3 for post-thrombectomy model. These nomograms will undergo external validation using prospective data to be presented at ISC 2026. Conclusions: Prognostication scales on pre- and post-EVT nomograms demonstrated that patients with larger ischemic lesions, older age and higher stroke severity had lower likelihood of independent ambulation. These nomograms will be externally validated through prospective data to assist in pre- and early post-procedure prognostication and represent an important advance toward individualized, evidence-based decision-making with significant implications in large-core stroke.