Introduction Clinical outcome is differed by the occluded location of M2 segment in endovascular thrombectomy (EVT). However, there is no report about the association between arterial diameter and outcomes.

Aim of Study We aimed to evaluate the relationship between arterial diameter of acute M2 occlusive patients treated with EVT and the outcomes.

Methods Using a prospective single center EVT registry, we identified acute M2 occlusion treated with EVT from 2011 to 2016. Diameter was measured at the proximal occluded segment using axial image of CT or MR angiography conducted before EVT. Procedural complication was captured including extravasation during angiography and hemorrhagic transformation on follow-up image.

Results A total of 104 patients (age, 70.2±11.9 years; male, 53.8%) was evaluated. M2 diameter was ranged from 1.05 to 3.19 mm. Six patients were treated with intraarterial urokinase only, 90 with stent retriever, 3 with aspiration thrombectomy, and 5 patients with both stent retriever and aspiration thrombectomy. Extravasation developed four times more frequently in the lowest quartiles (<1.63 mm) than the highest quartiles (≥2.29 mm) divided by M2 diameter. Hemorrhagic transformation occurred in 25%, and the half of them was subarachnoid hemorrhage. In the logistic regression analysis, the lowest quartile group showed positive association with hemorrhagic transformation (adjusted ORs 8.91 [95% CIs 1.50 – 52.93]), but no association with clinical outcome.

Conclusion This study demonstrated that the lowest quartile of M2 diameter was associated with procedural complication in the acute M2 occlusion patients treated with EVT. However, clinical outcome was not differed.

Disclosure of Interest Nothing to disclose