Related Experiment Video
Updated: Apr 22, 2026
Determining the Functional Status of the Corticospinal Tract Within One Week of Stroke
Published on: February 22, 2020
Early Postthrombectomy Neurological Improvement: the NIHSS Drop as an Immediate Predictor of Good Functional Outcomes
Pablo Baena-Palomino1,2, Marta Aguilar-Pérez3,4, Asier de Albóniga-Chindurza3,4
1Stroke Unit, University Hospital Virgen del Rocio, Seville, Spain. baenap7@gmail.com.
Purpose:
Despite advances in mechanical thrombectomy for acute ischemic stroke (AIS), the relationship between successful angiographic reperfusion and functional outcome remains imperfect. We investigated the value of an optimal immediate postthrombectomy National Institutes of Health Stroke Scale (NIHSS) cutoff, termed the "NIHSS drop," as a predictor of favorable 90-day outcome and compared its prognostic performance with first-pass effect (FPE).
Methods:
We conducted a single-center retrospective analysis of prospectively collected data from 554 patients with AIS who underwent mechanical thrombectomy between 2018 and 2024. Eligible patients presented with an NIHSS score > 8, an Alberta Stroke Program Early CT Score (ASPECTS) of 6-10, and M1 occlusion. Immediate postprocedural NIHSS assessment allowed calculation of the NIHSS drop. Receiver operating characteristic (ROC) analysis was used to determine the optimal cutoff, and logistic regression was used to assess its predictive value after adjustment for complete reperfusion (Thrombolysis in Cerebral Infarction [TICI] grade 3 vs 2b), FPE, and other major confounders.
Results:
An NIHSS drop ≥ 6 was strongly associated with favorable outcome (area under the curve [AUC] = 0.762, sensitivity 63%, specificity 82%). Patients with an NIHSS drop ≥ 6 (n = 235) had better outcomes (modified Rankin Scale [mRS] 0-2: 83% vs 40%, p < 0.001), fewer complications, and lower median NIHSS scores at 24 h (3 vs 12) and at discharge (1 vs 5), as well as lower in-hospital mortality (1.7% vs 15%, p < 0.001) and 90-day mortality (3.0% vs 19%, p < 0.001). In multivariable analysis, an NIHSS drop ≥ 6 remained the strongest predictor of favorable outcome (odds ratio [OR] 7.21, 95% confidence interval [CI] 4.62-11.5; p < 0.001), showing a stronger association than complete reperfusion or FPE individually.
Conclusion:
Immediate neurological improvement after thrombectomy was strongly associated with favorable functional outcome. An NIHSS drop ≥ 6 may serve as a useful early prognostic marker and may complement traditional procedural metrics such as TICI grade and FPE, although prospective validation is needed.
