Abstract
The selection of acute ischemic stroke (AIS) patients for mechanical thrombectomy (MT) is based on the clinical-radiological mismatch, where the NIHSS is higher than expected based on the ASPECT score. Our objective was to estimate the mismatch (NIHSS(mismatch%)) between the expected NIHSS (NIHSS(expected)) and the actual NIHSS (NIHSS(actual)) on admission, and to study its prognostic value for early neurological improvement (ENI, defined as a reduction of NIHSS of ≥ 8 points or reaching 0/1 at 24 h) in AIS patients with large vessel occlusion (LVO) of the anterior circulation treated with MT. A cross-sectional study was conducted on AIS related to anterior territory LVO (2017–2022) at a Stroke Center. Using multivariate linear regression models in the derivation cohort, a formula for calculating the NIHSS(expected) on admission was developed, and the NIHSS(mismatch%) between NIHSS(actual) and NIHSS(expected) was measured. Multivariate analyses were performed to identify if NIHSS(mismatch%) levels predicted ENI. In the derivation cohort (n = 123), the following formula was developed: NIHSS(expected) = 10.8 + 0.05 x Age + 2.5 x DM + 2.6 x Hemisphere – 1.5 x ASPECTS(admission). In the validation cohort (n = 185), 64 (34.6%) patients experienced ENI. The ROC curve identified 75% of NIHSS(mismatch%) as the optimal cutoff for predicting ENI (80% sensitivity and 58% specificity). Multivariate analyses showed that both NIHSS(mismatch%) and NIHSS(mismatch%) >75 were predictors of ENI (OR 1.062; 95% CI 1.033–1.092 and OR 5.687; 95% CI 2.562–12.623, respectively), adjusted for potential confounders. NIHSS(mismatch%) could be a predictor of ENI in AIS patients treated with MT. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1038/s41598-025-28303-z.