Recanalisation of middle cerebral artery occlusion after intra-arterial thrombolysis: Different recanalisation grading systems and clinical functional outcome

Abstract

Background: Different grading systems of arterial recanalisation have never been compared in large series of stroke patients treated with intra-arterial thrombolysis (IAT). Methods: Clinical and angiographic findings and outcome were analysed in 147 patients with M1 or M2 segment occlusion of the middle cerebral artery treated with IAT. Associations of the thrombolysis in myocardial infarction (TIMI) grading system and the Mori grading system with clinical outcome were compared. Results: The median NIHSS score on admission was 15 and the mean time from symptom onset to IAT was 242 minutes. After three months the outcome was favourable (defined as modified Rankin scale score (mRS) ≤2) in 85 patients (58%) and poor (mRS 3 to 5) in 44 (30%); 18 patients (12%) were dead. Recanalisation was categorised as TIMI grade 0 in 17 patients (12%), TIMI 1 in 16(11%), TIMI 2 in 83 (56%), and TIMI 3 in 31 (21%). Seventeen patients (12%) showed Mori grade O reperfusion, 16(11%) Mori 1, 37 (25%) Mori 2, 46 (31%) Mori 3, and 31 (21%) Mori 4. In both TIMI and Mori grading systems, reopening the artery was an independent predictor of a favourable clinical outcome (p<0.0001). When recanalisation was partial, outcome was better in patients with reperfusion >50% (Mori 3) than in those with reperfusion <50% (Mori 2) (p=0.008). Conclusions: Both TIMI and Mori grading systems are useful for predicting outcome after stroke and IAT. When recanalisation is partial the Mori classification is more refined in giving prognostic information.