Background and Aims: About 40% of patients have poor functional outcome even after modern endovascular treatment (EVT), which is strongly requiring post-EVT therapies targeting damages from ischemia-reperfusion. Futile or effective reperfusion can be a significant noise in assessing efficacy of post-EVT therapies. Thus, we investigated whether post-EVT NIHSS score better discriminates long-term outcomes after EVT.
Methods: We identified 566 stroke patients who received EVT at Seoul National University Bundang Hospital between Apr 2008 and Dec 2015. We prospectively collected post-EVT NIHSS score, which was measured by on-duty physician right after completion of EVT. The prognostic values of post-EVT NIHSS score, recanalization status and other baseline profiles in discriminating favorable 3-month outcome (modified Rankin Scale 0-2) were assessed using 4 different logistic regression models (Figure). The c-statistic was used as the primary measure of model discrimination. The integrated discrimination index (IDI) and the category-free net reclassification index (NRI) were also compared.
Results: The post-EVT NIHSS score was 11.8 ± 7.8 pts, which showed overall improvement of 2.3 ± 6.3 pts compared to the baseline NIHSS score (14.0 ± 7.1 pts). Any change of NIHSS score was present in 79%. Favorable 3-month outcome was achieved in 47% of patients. Based on the results of differences among the c-statistics, both model 3 and model 4 were significantly more discriminative of favorable outcome than model 1 or model 2 (Figure). Model 4 showed significant improvement of both IDI and NRI as compared to all other models, but the magnitude from model 3 to model 4 was modest (IDI, 0.021; NRI, 0.322).
Conclusions: Post-EVT NIHSS score was the strongest factor in discriminating long-term outcomes after EVT, which was superior to baseline NIHSS or recanalization status. Therefore, post-EVT NIHSS score should to be considered when assessing the efficacy of post-EVT therapies.