ABSTRACT NUMBER: ESOC2026LB122 INTRAVENOUS THROMBOLYSIS BEYOND THE TIME WINDOW IN REAL-WORLD PRACTICE: COMPARATIVE OUTCOMES AND PREDICTION MODEL FOR ACUTE ISCHEMIC STROKE

Abstract Background and aims The real-world data of intravenous thrombolysis (IVT) for acute ischemic stroke (AIS) in the extended time window (ETW) remain limited. We aim to evaluate the efficacy of IVT in the ETW and develop a simplified score to guide IVT. Methods We analyzed AIS patient data from the CASE-II registry, a prospective multicenter stroke registry in China between January 2017 and December 2024. Patients were categorized into IVT and non-IVT groups, and those receiving IVT were further stratified by ONT into standard time window (STW, ≤4.5h) and ETW (4.5–24h) groups. Primary outcome was 3-month functional independence (mRS 0-2). Multivariable logistic regression was performed. The performance of the prediction model for IVT in the ETW was developed and validated using bootstrap resampling. Results Of the 57,787 patients receiving IVT, 3,050 (5.28%) were treated in the ETW, with annual cases rising from 62 (5.44%) in 2017 to 826 (7.05%) in 2024. In the ETW group, the IVT group had superior functional independence (P=0.035) compared with the non-IVT group. Additionally, the ETW group showed reduced functional independence (P<0.001), with no significant difference in 3-month mortality compared with the STW group. The 12-point model for IVT in the ETW showed good discrimination in predicting functional independence (training AUC: 0.803; validation AUC: 0.789). Conclusions Our findings suggest that although IVT in the ETW is slightly less effective than in the STW, it still offers a clear benefit over no IVT. The proposed prediction model may help identify ETW patients most likely to benefit from treatment. Conflict of interest Figure 1 - belongs to Conclusions