Abstract TMP73: Early Neurological Improvement: A Search for a Definition

Abstract

Background: Early neurological improvement (ENI) is a metric that has been increasingly used to prognosticate favorable long-term clinical outcome following emergent large vessel occlusion (ELVO) treated by mechanical thrombectomy (MT). However, there is no clear consensus on what definition of ENI most accurately portends favorable long term clinical outcome. Definitions have varied from absolute differences in NIH Stroke Scale (NIHSS) to percentage reduction of NIHSS shortly after mechanical thrombectomy. In our analysis, we compared different definitions of ENI and how accurately they predicted favorable long-term clinical outcome. Methods: A review of all patients presenting to a comprehensive stroke center from January 2016 to December 2018 with ELVO treated by MT. Inclusion criteria were patients treated with MT for ELVO and who had documented admission NIHSS, NIHSS at day 0, NIHSS at day 1, and modified Rankin score (mRS) at 90 days. ENI definitions examined were: 1) reduction of day 1 NIHSS by > 8 compared to admission NIHSS or day 1 NIHSS of < 2, 2) > 30% reduction of NIHSS at day 0 compared to admission NIHSS, and 3) > 40% reduction of NIHSS at day 1 compared to admission NIHSS. Favorable long-term outcome was defined as mRS of 0-2 at 90 days. Positive predictive values (PPV), sensitivities, and specificities were calculated for each of the three definitions for favorable long term outcome. Results: A total of 227 patients met inclusion criteria for this study. Favorable long term clinical outcome was met in 126/227 (55.5%). Definition 1 had a sensitivity of 62.38%, specificity of 67.46%, and PPV of 60.58%. Definition 2 had a sensitivity of 45.54%, specificity of 77.78%, and PPV of 62.16%. Definition 3 had a sensitivity of 69.31%, specificity of 69.84%, and PPV of 64.81 %. Conclusion: In our cohort, ENI as defined by > 40% reduction of NIHSS at day 1 from admission NIHSS, was most predictive of favorable long term clinical outcome