Abstract A006: The Time-Dependent Impact of Mismatch Profiles on Outcomes Following Endovascular Thrombectomy for Large Ischemic Stroke

Background: Endovascular therapy (EVT) has demonstrated efficacy in patients with large core infarctions, yet favorable outcomes remain limited. While mismatch profiles have long informed EVT decision-making in small-core strokes, their prognostic significance in large-core infarcts remains uncertain and may be affected by time from symptom onset. This study aims to evaluate the relationship between mismatch profiles, time distribution, and EVT efficacy in patients with large ischemic cores. Methods: This was a secondary analysis of the ANGEL-ASPECT trial in patients with large ischemic cores randomized to EVT or medical management. Baseline imaging included noncontrast CT, CT or MR angiography, and perfusion imaging. The primary outcome was independent ambulation (modified Rankin Scale score 0–3) at 90 days. Analyses were stratified by mismatch profile (mismatch ratio ≥1.8 and volume ≥15 mL) and onset-to-imaging time ( 6 hours vs. >6 hours). Results: Among 426 patients, 81.2% demonstrated a mismatch profile. Mismatch prevalence increased with longer onset-to-imaging times (P = 0.0047). In the early window ( 6 hours), EVT significantly improved independent ambulation in patients with mismatch (48.9% vs. 28.4%, OR 2.41, 95% CI 1.28–4.55, p = 0.0063) but not in unmismatch patients (23.8% vs. 27.3%, OR 0.83, 95% CI 0.21–3.29, p = 0.7949). In the late window (>6 hours), EVT did not significantly improve independent ambulation in either mismatch or unmismatch patients. Conclusions: Among patients with large infarct cores, unmismatch profile is more frequently observed in the early time window and is associated with diminished benefit from EVT. These results emphasize the importance of mismatch evaluation, even in early-presenting patients, to guide optimal treatment selection in patients with large ischemic cores. Trial registration number: NCT04551664.