Ultra-early improvement after endovascular thrombectomy and long-term outcome in anterior circulation acute ischemic stroke

Background: The use of post-treatment measures after acute ischemic stroke is important to predict good functional outcome. The most studied is 24 h National Institutes of Health Stroke Scale (NIHSS) score and existing literature is scarce regarding the use of earlier indicators, namely NIHSS immediately after endovascular thrombectomy (EVT). We hypothesized that an immediate neurological improvement after EVT, that we called ultra-early neurological improvement (UENI), would be a reliable functional independence predictor in anterior circulation acute ischemic stroke patients. Methods: We included 296 anterior circulation stroke patients who received EVT at our institution between January 2015 and December 2017. We obtained post-EVT NIHSS score in the angiography room. UUENI was defined as a >= 4 point decrease in post-EVT NIHSS score relatively to baseline or post-EVT NIHSS score of 0-1. Patients' functional outcome was assessed using the modified Rankin Scale at 3 months. The ability of UENI to predict good functional outcome was assessed using logistic regression analysis. Results: A total of 155 (52.4%) patients presented UENI. This group of patients achieved a statistically significant higher rate of functional independence (70.3% vs 46.8%, OR crude 2.69, 95% CI 1.67-4.34). After adjusting for potential confounders, the UENI showed to be an independent predictor of good outcome, with UENI patients having 4.61 times the probability of obtaining good outcome compared to patients without UENI. Conclusions: UENI is useful in outcome prediction in patients with anterior circulation stroke treated with EVT, with the advantage that it can be assessed at an ultra-early stage.