Abstract 489: Impact of Time to Puncture on Functional Outcomes in Distal/Medium Vessel Occlusion Thrombectomy

Introduction/Purpose The influence of time to arterial puncture in endovascular therapy (EVT) compared with best medical management remains uncertain. ESCAPE‐MEVO suggested that treatment benefit diminishes beyond 6 hours, whereas DISTAL did not demonstrate a significant association between time and functional outcome, underscoring the need for further study. We evaluated whether last‐known‐well (LKW) to arterial puncture time impacts 90‐day functional outcomes among patients with MeVO treated with EVT. Materials/Methods We conducted a retrospective cohort observational cohort study of a prospectively maintained, dual‐center database including all consecutive patients with primary MeVOs (distal or non‐dominant M2, M3, A2‐A3, P1‐P2) who underwent EVT between January 2022 and July 2024. Patients were divided into an early window (<6 hours from LKW to puncture) and a late window (≥6 hours). The primary outcome was functional independence (modified Rankin Scale mRS: 0‐2) at 90 days. Secondary outcomes included 90 day ordinal mRS shift and mortality. Results Among 231 patients (median age 79 IQR 69‐85, 53.9% male), 129 (55.8%) were treated in the early window and 102 (44.2%) in the late window. Median admission NIHSS was 9 (IQR 6‐14). LKW‐to‐puncture was 217 min (IQR 150‐292) in the early group and 617 min (IQR 470‐902) in the late group. Wake‐up strokes were more common in the late window (56.9% vs 5.4%, p<0.001), and IV tPA use was more frequent in the early window (45.0% vs 16.7%, p<0.001). There were no differences in ASPECTS, occlusion distribution, or perfusion imaging parameters. There was a non‐significant trend toward higher rates of reperfusion in the early group (eTICI 2C‐3: 69.5% vs 57.4%; p=0.058). After adjusting for age, sex, baseline NIHSS, baseline mRS, IV tPA, and occlusion location, late‐window treatment was not associated with lower odds of good outcome (aOR 0.81, 95% CI 0.43‐1.50; p=0.511), ordinal mRS shift (aOR 0.84, 95% CI 0.52‐1.36; p=0.476), or increased mortality (aOR 0.90, 95% CI 0.45‐1.76; p=0.753) ( Figure ). Conclusion In this multicenter MeVO cohort, EVT performed beyond 6 hours was not associated with worse outcomes, suggesting that thrombectomy may remain effective in appropriately selected patients treated in the late window. image