Characteristics and prognostic impact of unsuccessful recanalization after endovascular therapy for acute ischemic stroke

Background: Endovascular therapy (EVT) has shown high therapeutic efficacy for acute large vessel occlusion (LVO); however, recanalization is unsuccessful in some cases. This study aimed to examine the characteristics and prognostic impact of unsuccessful recanalization after EVT compared with medical treatment alone. Methods: We conducted a post hoc analysis of RESCUE-Japan Registry 2, a nationwide registry of 2408 consecutive patients with acute LVO. Patients without successful recanalization after EVT (thrombolysis in cerebral infarction grade <= 2a) were classified into the Unsuccessful EVT group, and compared with the No-EVT group. To account for selection bias, the outcomes were compared in a propensity score-matched cohort. The outcomes included the modified Rankin Scale (mRS) score at 90 days and intracranial hemorrhage within 72 h after the LVO onset. Results: Among 188 (14.7 %) patients in the Unsuccessful EVT group out of 1281 who underwent EVT, 147 were matched with the No-EVT group, with comparable baseline characteristics. Patients in the Unsuccessful EVT group had a higher distribution of mRS score at 90 days and were less likely to achieve mRS 0-2 compared to those in the No-EVT group (23 % vs. 34 %, OR:0.58, 95 % CI:0.35-0.98). All-cause mortality was higher in the Unsuccessful EVT group (16 % vs. 6.8 %, OR: 2.54, 95 % CIs: 1.16-5.55). Symptomatic intracranial hemorrhage was more frequently observed in the Unsuccessful EVT group (5.4 % vs. 0.7 %, OR: 8.40, 95 % CIs: 1.04-68.1). Conclusions: The clinical outcomes of patients without successful recanalization after EVT were worse than those who did not undergo EVT.