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 0 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.

The Clinical and Radiographic Importance of Distinguishing Partial from Near-Complete Reperfusion Following Intra-Arterial Stroke Therapy

“…There are several schema available for classifying angiographic results, including the Mori scale, 5 TIMI, the arterial occlusive lesion score from IMS, and the original TICI and the modified TICI, with 2a and 2b defined separately. The relationship between these schema and outcomes, including comparison of TIMI and Mori schemes and comparison of outcomes based on TIMI, has also been done, 13 with both of those series suggesting a benefit to partial reperfusion. However, the definition of partial reperfusion is key, with TIMI 2 (encompassing both 2a and 2b) considered partial reperfusion in both of those series.…”

Predictors of Hemorrhage Following Intra-Arterial Thrombolysis for Acute Ischemic Stroke: The Role of Pial Collateral Formation

“…13 Patients with no reperfusion were classified as Mori 0, patients between 0% and 50% reperfusion were classified as Mori 1, patients between 50% and 100% reperfusion were classified as Mori 2, and patients with 100% reperfusion were classified as Mori 3.…”

Revascularization grading in endovascular acute ischemic stroke therapy

“…Subsequent evaluation of the Mori grading system demonstrated association with clinical outcome and suggested that the expanded distinction of reperfusion categories may improve outcome prediction. 14 …”

“…13 Some applications of the TIMI scale that have been associated with clinical functional outcomes have been demonstrated in studies of intra-arterial thrombolysis for AIS. 13,14 The variability in the operating manual/grading definition of the TIMI scoring system is the main disadvantage of its use across clinical trials; however, its biggest advantage is its simplicity and familiarity to many stroke neurologists and neurointerventionalists.…”