Advanced Imaging-Guided Intravenous Thrombolysis Beyond 4.5 Hours: A Single-Center Experience in Mexico

Introduction Intravenous thrombolysis is the standard treatment for acute ischemic stroke within the first 4.5 hours; however, many patients present with unknown symptom onset or delayed presentation. Advanced neuroimaging allows identification of salvageable brain tissue and extension of the therapeutic window up to nine hours, and recent evidence suggests that, in carefully selected patients, reperfusion may be beneficial up to 24 hours after stroke onset. Objective The objective of this study is to report the institutional experience with advanced imaging-guided intravenous thrombolysis in the extended therapeutic window, including its frequency of use and workflow times. Methods We conducted a retrospective, descriptive study including consecutive patients with acute ischemic stroke who received intravenous thrombolysis between March 2022 and May 2025. Patients treated beyond 4.5 hours after symptom onset or with unknown onset time were identified and analyzed. Eligibility for thrombolysis was determined using computed tomography (CT) perfusion or magnetic resonance imaging (MRI) mismatch criteria. Descriptive analyses were performed using IBM SPSS Statistics for Windows, Version 27 (Released 2019; IBM Corp., Armonk, NY, USA). Results Fourteen patients (17.7%) out of a total of 79 were identified. Female sex predominated (79%), with a mean age of 67 ± 17 years and a median National Institutes of Health Stroke Scale (NIHSS) score of 9 points. The most frequently affected territory was the anterior circulation (79%), primarily the middle cerebral artery. Onset was unknown in 36% of cases. Median time from symptom onset was 327 minutes; door-to-imaging time was 30 minutes, and door-to-needle time was 74 minutes. No in-hospital mortality was recorded. Conclusions Advanced imaging-guided thrombolysis is feasible in tertiary care centers in Mexico, thereby expanding access to reperfusion therapy for patients with delayed presentation.