Reperfusion‐Dependent Outcomes After Endovascular Thrombectomy Stratified by NIHSS ‐ ASPECTS Clinical‐Core Mismatch

ABSTRACT Objective This analysis evaluates the effect of successful reperfusion on functional outcomes after MT, stratified by admission National Institutes of Health Stroke Scale (NIHSS) and Alberta Stroke Program Early CT Score (ASPECTS) as surrogates for clinical‐core mismatch, using multicenter registry data. Methods Retrospective analysis of patients with anterior circulation stroke undergoing MT enrolled in the German Stroke Registry (2015–2023). Patients were stratified into nine subgroups according to ASPECTS (10; 9–8; ≤ 7) and NIHSS (0–10; 11–15; ≥ 16). The primary endpoint was the rate of good functional outcome (modified Rankin Scale mRS of 0–2) at 90 days. Safety outcomes included symptomatic intracranial hemorrhage and mortality. Inverse‐probability‐weighted regression adjustment (IPWRA) was used to control confounders in observational data. Results 18,069 patients were screened, 5448 met the inclusion criteria (mean age 71.2; 48% female). Successful reperfusion (mTICI 2b‐3) was associated with improved functional outcomes in all subgroups, including patients with low NIHSS and high ASPECTS or high NIHSS and low ASPECTS. Largest effects were observed for high clinical‐core mismatch (ASPECTS = 10; NIHSS ≥ 16) with 47% (95% Confidence Interval CI: 42%–53%) mRS 0–2 after mTICI 3 recanalization compared to 9% (95% CI: 3%–16%) after persistent occlusion, a 38‐percentage point increase in good outcome. mTICI 3 was associated with superior outcomes compared to mTICI 2b, particularly in patients with high NIHSS and high ASPECTS. Interpretation Patients with pronounced clinical‐core mismatch derive the greatest benefit from successful reperfusion. Nonetheless, significant functional improvements across all subgroups support more individualized treatment considerations and highlight the need for refined selection criteria.