Mechanical thrombectomy in acute middle cerebral artery M2 segment occlusion with regard to vessel involvement

Endovascular treatment (EVT) is an established procedure in patients with acute ischemic stroke due to occlusion of the proximal M1-segment of middle cerebral artery. The assessment of distal thrombectomy in daily clinical routine has not yet been sufficiently evaluated. Patients with M2-segment-occlusions treated by EVT in the local department (January 2012–December 2017) were included (n = 57, mean National-Institutes-of-Health-Stroke-Scale of 11, range 0–20). Patients were grouped according to localization of M2-occlusion (Cohort A (n = 14): central region only, B (n = 24): central region and involvement of frontal vessels, C (n = 19): parietal, occipital, and/or temporal vessels). Differences in proximal (M2-trunk, n = 34) and distal (M2-branches, n = 23) occlusions were also examined. Reperfusion (Thrombolysis-In-Cerebral-Infarction (TICI)), early clinical outcome at discharge (modified Rankin Scale (mRS)), and complications (hemorrhage, new emboli) were noted. Successful reperfusion (TICI2b–3) was found in 49 patients (86.0%). Favorable early clinical outcome (mRS0–2) was achieved in n = 19 (37.7%). Compared to admission, mRS at discharge improved significantly (median (admission) 5 vs. median (discharge) 4, p