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

Background 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. Methods 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. Result 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 < 0.001). Early clinical outcome was more favorable in patients with better reperfusion (TICI2b-3: mean mRS 3 ± 1.7 vs. TICI0–2a: mean mRS 4.4 ± 1.4, p = 0.037). Six (10.5%) patients suffered from symptomatic intracranial hemorrhage during treatment or hospitalization. Four patients died (7.0%). No significant differences in favorable clinical outcome (mRS ≤ 2: Cohort A 42.9%, B 50.0%, C 16.7%, p = 0.4; χ 2 -test) or periinterventional complications were found with regard to vessel involvement. Conclusion EVT in patients with acute M2-occlusion is safe and leads to a significant clinical improvement at discharge. No significant differences in clinical outcome or complications were found with regard to the localization of the M2-occlusion.