Mechanical thrombectomy in MCA-mainstem occlusion in patients with low NIHSS scores

Introduction While effectiveness of mechanical thrombectomy (MTE) in M1 segment occlusion is approved for patients with severe impairment, there is a lack of evidence for a potential benefit of MTE in patients with minor to moderate symptoms. The purpose of this study was to evaluate neurological outcome and occurrence of periprocedural complications after MTE in patients with low National Institutes of Health Stroke Scale (NIHSS) scores. Materials and methods A retrospective analysis of 1081 consecutive patients with anterior circulation ischemic stroke due to M1 occlusion detected by computed tomography angiography and treated with MTE at our hospital between February 2012 and November 2017 was performed. NIHSS, Barthel Index (BI) and modified Rankin Scale (mRS) scores between admission and discharge were compared with paired Mann-Whitney test, and recanalization rate and complications were assessed in patients with NIHSS ≤ 5 at admission. Results Thirty patients were included with a median NIHSS score of 4. NIHSS score (median: 4 vs. 1; p < 0.001), BI (median: 43 vs. 80; p < 0.001) and mRS (2 vs. 1; p < 0.001) showed significant improvement from admission to discharge after MTE. Recanalization rate was Thrombolysis in Cerebral Infarction (TICI) 2b to 3 in 29 of 30 patients (96.7%). One case of an intracerebral reperfusion hematoma (ECASS: PH2) required surgical treatment. Conclusion MTE might lead to a significantly improved clinical outcome also for patients with low NIHSS score due to M1 segment occlusion. Periprocedural complications appeared infrequently. These results encourage further evaluation of the benefit-risk profile of MTE compared to standard treatment in patients with low NIHSS scores in future randomized trials.