BACKGROUND AND OBJECTIVES: Endovascular treatment (EVT) for medium vessel occlusion (MeVO) raises concern about hemorrhagic complications; however, its clinical impact has not been elucidated. Therefore, we investigated the association between intracranial hemorrhage (ICH) after EVT for MeVO and functional outcomes. METHODS: We conducted a post hoc analysis of the Japan Registry of NeuroEndovascular Therapy 4, a nationwide registry in Japan from 2015 to 2019 including 13 479 patients who underwent EVT for acute ischemic stroke. This study included 2465 patients with MeVO from 166 participating centers in Japan. We compared patients who underwent EVT for MeVO according to their hemorrhagic complication after EVT (no ICH, asymptomatic ICH, and symptomatic ICH). Outcomes included a modified Rankin scale (mRS) score at 30 days and all-cause mortality within 30 days. We estimated the odds ratios (ORs) and their CIs using a multivariable logistic regression model. RESULTS: Among 2394 patients analyzed, 302 (12.6%) developed ICH, with 95 (31.5%) being symptomatic. Compared with the no-ICH group (n = 2092), the asymptomatic and symptomatic ICH groups had a lower proportion of patients with an mRS score of 0 to 2 at 30 days (41% vs 34%, vs 7.4%, P for trend &lt;.001), with an adjusted ORs of 0.77 (95% CI, 0.53-1.12) and 0.12 (95% CI, 0.05-0.30) in the asymptomatic and symptomatic ICH groups, respectively. The adjusted common ORs of one-point shift of mRS score at 30 days in the asymptomatic ICH group was 0.76 (95% CI, 0.57-0.99) and that of the symptomatic ICH group was 0.13 (0.07-0.23), compared with the no-ICH group. CONCLUSION: ICH after EVT for MeVO was associated with worse outcomes, whether they were symptomatic or not. The optimal treatment devices or techniques to reduce ICH after EVT for MeVO are crucial.

Impact of Intracranial Hemorrhage After Endovascular Treatment for Medium Vessel Occlusion