Abstract DP336: Thrombectomy Utilization and Outcomes for Patients with Large Vessel Occlusions Presenting After 24 Hours

Introduction: Thrombectomy is established as standard of care for select patients with an acute large vessel occlusion (LVO) up to 24 hours from last known normal (LKN) based on randomized trial inclusion criteria. The benefit of intervention after 24 hours has not been established and there are limited data on thrombectomy utilization in this time window in current practice. We aimed to describe the proportion of patients receiving thrombectomy in this very late window and to compare their clinical outcomes to patients treated earlier. Methods: Using American Heart Association/American Stroke Association Get With The Guidelines-Stroke registry data, we identified patients presenting to a Comprehensive or Thrombectomy-Capable Stroke Center with an internal carotid, M1, or M2 occlusion and NIHSS ≥6. Using generalized estimating equations adjusted for patient- and hospital-level characteristics, the odds of thrombectomy, discharge functional independence (modified Rankin 0–2), and ambulatory status among those arriving >23.5 hours after LKN were compared to those arriving within 5.5–23.5 hours. Results: Between January 1, 2018, and June 30, 2024, there were 39,427 patients with an ischemic stroke presenting between 23.5–48 hours, of which 3,373 (8.6%) had a proximal anterior LVO with NIHSS ≥6. Of these LVO patients, 1,789 (53.0%) underwent thrombectomy. In contrast, 24,409 of 34,163 LVOs (71.4%) arriving 5.5–23.5 hours after LKN received thrombectomy. Patients arriving after 23.5 hours were predominantly similar in patient and hospital characteristics including age and stroke severity (Table). Compared to patients receiving thrombectomy within 5.5–23.5 hours, patients treated after > 23.5 hours were less likely to be functionally independent (OR 0.70 [0.60–0.82], p<0.001) and ambulating independently (OR 0.73 [0.64–0.83], p<0.001). The incidence of symptomatic hemorrhage in patients treated >23.5 hours was 5.5%, compared to 6.9% in patients treated between 5.5–23.5 hours (p=0.546). Conclusions: In this largest ever analysis of late-presenting LVOs, patients presenting >23.5 hours after LKN were less likely to undergo thrombectomy compared to patients arriving earlier. The odds of independent ambulation and functional independence at hospital discharge were also reduced compared to patients presenting earlier, despite similar safety. Prospective clinical trials are needed to determine whether very late thrombectomy improves outcomes.