Background: There have been different methods in clinical trials to quantify partial angiographic recanalization after mechanical thrombectomy for large vessel acute ischemic stroke.
Objective: To determine the variation in quantification between different methods for grading angiographic recanalization.
Methods: We reviewed clinical and angiographic data for consecutive patients who underwent mechanical thrombectomy at a single center. The post procedural angiographic recanalization was graded using three different methods which were used by the Interventional Management of Stroke III (IMSIII) trial investigators (filling>50% of territory affected), Endovascular treatment for Small Core and Anterior circulation Proximal occlusion with Emphasis on minimizing CT to recanalization times (ESCAPE) trial investigators (filling all branches but with delay) and definition used by Multicenter Randomized Clinical trial of Endovascular treatment for Acute ischemic stroke in the Netherlands (MRCLEAN) investigators (filling of more than 66% of territory affected).
Results: Post procedural angiograms were reviewed for 61 consecutive patients (mean age ± SD, 73.52 ± 14.4, 26 were men) who underwent mechanical thrombectomy. The initial median NIHSS score was 14.The occlusion site was in middle cerebral artery (n= 39), internal carotid artery (n= 15), anterior cerebral artery (n = 3), posterior cerebral artery (n = 1), orbital artery (n = 2), basilar artery (n = 1) TICI 2b was categorized in 19 patients by IMS III definition and in 12 patients by MRCLEAN criteria that was categorized 2a by ESCAPE method. TICI 2b was categorized in 19 patients by IMS III method was categorized as 2a by the MRCLEAN definition. The rate of favorable outcome (mRS 0-2) in patients classified as TICI 2b in IMS III was 10 of 19 (52.6%) but not in other trials was 24 of 42(57%).
Conclusions: The differences in definitions used between trials and impact upon rates of partial recanalization (TICI 2b) reported should be recognized