Risk Factors of Futile Recanalization Following Endovascular Treatment in Patients With Large-Vessel Occlusion: Systematic Review and Meta-Analysis.

Background: Although successful recanalization (modified Thrombolysis in Cerebral Infarction score 2b-3) can be achieved in >80% of patients experiencing stroke attributable to large-vessel occlusion, up to 50% of patients may develop poor clinical outcomes (modified Rankin scale score at 90 days of 3-6), termed as futile recanalization (FR). The meta-analysis aims to determine various risk factors associated with FR. Methods: In February 2021, a comprehensive literature search on risk factors associated with FR was performed with keywords, including "stroke," "thrombectomy," "treatment outcome," and "risk factors." Their correlations with FR were evaluated using the random effect size meta-analysis model. Results: Twenty studies with 3037 patients were included with an FR rate of 51.0%. Our meta-analyses showed that age (mean difference [MD], 5.6; 95% CI, 4.7-6.6), National Institutes of Health Stroke Scale score (MD, 4.2; 95% CI, 3.2-5.1), Alberta Stroke Program Early Computed Tomography (CT) Score (MD, -0.5; 95% CI, 0.8-0.3), hypertension (odds ratio [OR], 1.5; 95% CI, 1.3-1.9), systolic blood pressure (MD, 6.9; 95% CI, 3.6-8.7), atrial fibrillation (OR, 1.5; 95% CI, 1.2-1.8), IV tPA (tissue-type plasminogen activator) (OR, 0.7; 95% CI, 0.5-0.8), puncture to recanalization time (MD, 9.6; 95% CI, 5.3-13.8), and time of onset to recanalization (MD, 32.1; 95% CI, 6.5-47.7) were significantly associated with FR (P<0.001). Conclusions: Age, admission National Institutes of Health Stroke Scale score, Alberta Stroke Program Early CT Score, comorbidities, including hypertension, systolic blood pressure, atrial fibrillation, and use of IV tPA, as well as time frames, including onset to recanalization and onset to arrival, were significant influencing factors for FR after mechanical thrombectomy. Future research on the mechanism underlying FR is warranted.