Abstract
BACKGROUND: The impact of endovascular therapy (EVT) timing within the 24-h window on tissue injury and post-ischemic inflammation in large-vessel occlusion stroke remains uncertain. METHODS: In a single-center prospective cohort, 216 anterior circulation large-vessel occlusion patients treated with EVT ≤ 24 h were stratified by onset-to-groin time: 0-6 h (n = 74), 6-12 h (n = 72), and 12-24 h (n = 70). Serial IL-6, TNF-α, IL-1β, MMP-9, C-reactive protein, and neutrophil-to-lymphocyte ratio were measured to 72 h; reperfusion quality, final infarct volume, infarct progression, NIHSS change, and 90-day modified Rankin Scale (mRS) were compared. RESULTS: Baseline demographics, risk factors, stroke severity, and inflammatory profiles were similar across groups. Earlier EVT yielded higher mTICI 2b-3 rates and more first-pass effect, with fewer device passes and shorter procedures. Final infarct volume increased stepwise with delay (38.7, 51.3, and 64.5 mL in the 0-6 h, 6-12 h, and 12-24 h groups), paralleled by greater infarct progression. NIHSS improvement at 24 h and day 7 was greatest in the 0-6 h group, and functional independence at 90 days declined with later treatment (mRS 0-2: 64.9% vs 50.0% vs 35.7%). Symptomatic intracranial hemorrhage, procedural complications, and in-hospital mortality were low and comparable. Patients treated within 0-6 h showed blunted peaks and faster resolution of IL-6, MMP-9, C-reactive protein, and neutrophil-to-lymphocyte ratio, consistent with a more favorable neuroinflammatory trajectory. These associations remained consistent in adjusted and sensitivity analyses. CONCLUSION: Within 24 h, earlier EVT was associated with more favorable reperfusion metrics, smaller infarct burden, lower circulating inflammatory biomarkers, and better 90-day functional outcome, without an apparent increase in major safety events. Given the observational design, these findings should be interpreted as associations rather than causal effects.