Characteristics of Unsuccessful Recanalization Following Endovascular Thrombectomy: Cohort Study (EVATRISP Collaboration).

Background Successful target vessel recanalization in patients with large vessel occlusion stroke is associated with favorable clinical outcomes. Conversely, unsuccessful recanalization (UR) is associated with higher chances of poor outcomes. UR occurs in up to 30% of endovascular thrombectomy (EVT) procedures, and there are significant knowledge gaps in identifying factors associated with UR.Methods Prospectively enrolled EVT-treated patients from the EVATRISP registry, which included patients from 18 academic medical centers across Europe between the years 2015 and 2024, were retrospectively studied. Patients had to have data on prestroke and 3-month functional status and recanalization status at the end of EVT. UR was defined as a modified Thrombolysis in Cerebral Infarction score <2b and compared with successful recanalization (modified Thrombolysis in Cerebral Infarction ≥2b). Regression analyses were performed to identify predictors of UR, and a predictive tool was subsequently constructed.Results Of the 15 549 patients enrolled in EVATRIPS, 10 942 fulfilled entry criteria and were included in the current analysis. Overall, 8000 (73%) achieved successful recanalization, while 2942 (27%) had UR. In multivariate analysis, factors independently associated with higher odds of UR included older age, higher prestroke mRS, wake-up stroke, interhospital transfer for EVT, higher National Institutes of Health Stroke Scale score at presentation, tPA (tissue-type plasminogen activator) administration, and occlusion of the M2 segment of the middle cerebral artery or proximal anterior or posterior cerebral arteries. Dyslipidemia and occlusion of the M1 middle cerebral artery or basilar artery were associated with successful recanalization. UR was associated with poor clinical outcomes, and higher mortality rates. A predictive tool derived from these variables demonstrated limited discriminatory ability (area under the curve, 0.579 95% CI, 0.567-0.591; P<0.001).Conclusions UR is frequent among patients undergoing EVT and is associated with poor clinical outcomes. Although several pre-EVT factors were independently associated with UR, accurately predicting which patients will experience UR remains highly challenging. Our findings suggest that all eligible patients should undergo EVT.