In the 204 participants with severe stroke ( National Institutes of Health Stroke Scale 20 ) , a greater proportion of the endovascular group had a modified Rankin Scale 2 ( 32.5 % ) at 12 months as compared with the intravenous tissue-type plasminogen activator group ( 18.6 % , P = 0.037 ) ; no difference was seen for the 452 participants with moderately severe strokes ( 55.6 % versus 57.7 % ) .