Abstract TMP8: Post-thrombolysis Changes in DWI Lesion Volume and Correlation with Good Clinical Outcome

Abstract

Objectives and Hypothesis: Studies investigating the change of the DWI volume after thrombolysis have not demonstrated a consistent correlation with clinical outcome. Our objective was to quantify the DWI change at 2 hours and compare to the change in NIHSS in a large homogeneous stroke patient population. Our hypothesis is that patients with a decrease in DWI volume at 2 hours have a better clinical outcome compared to patients with no decrease. Methods: Patients were selected from the Lesion Evolution of Stroke and Ischemia On Neuroimaging (LESION) Project if they: had a pre-treatment MRI with evaluable DWI, were treated with standard IV-tPA, and had post-treatment MRI with evaluable DWI at 2 and 24 hours. A reader measured the DWI volumes using a validated technique. A vascular neurologist scored the NIHSS at pre-treatment, 2 and 24 hours and the mRS at discharge, 5, 30 and 90 days. The Chi-Squared, independent samples median and Mann-Whitney U tests were used to demonstrate differences between groups. Results: Seventy-one patients met the study criteria with a mean (±SD) age of 71.6 (±16.4) years, 58% women (n=41), median baseline NIHSS of 9 (IQR25-75: 4-18), median onset of 45 minutes (30-65) and median first MRI to start of thrombolysis of 47 minutes (39-59). The median pre-treatment and 2 hour DWI volumes were 8.4 ml (2.1-51.5) and 11.4 (3.6-54.7). Sixteen patients (23%) had a decrease in DWI volume > 2 ml at 2 hours versus 55 (77%) had an increase or no change at 2 hours (p=0.000). Of the 16 patients with a decrease in DWI volume > 2 ml at 2 hours, 10 (63%) had a mRS=0 or 1, while 20 (36%) of the 55 patients with no decrease had a mRS=0 or 1 (p=0.192). Limiting the analysis to the 43 patients with a pre-treatment DWI lesion ≥ 5 ml, there was a significant difference in mRS between the 15 patients with a decrease in DWI volume > 2 ml at 2 hours versus the 28 patients with no decrease, median of 1 versus 4, (p=0.014). There was also a significant difference in mRS distribution between these groups, (0-3 versus 2-6, p=0.008). Conclusions: In patients with a substantial pre-treatment DWI lesion volume, the decrease of DWI volume at 2 hours post-thrombolysis is a significant predictor of good clinical outcome.