Complete Recanalization May Exert the Most Important Effect on Outcomes of Endovascular Treatment in Acute Ischemic Stroke with Small Infarct Core Beyond 6 Hours

Abstract

To explore the differences among grades of recanalization on outcomes of endovascular treatment for acute anterior large vessel occlusion with small infarct core beyond the 6-hour time window. Patients beyond the 6-hour time window with Alberta Stroke Program Early Computed Tomography Score >7 were retrospectively enrolled from the endovascular treatment for acute anterior circulation ischemic stroke (ACTUAL) registry. They were divided into 3 groups according to the degree of recanalization: modified treatment in cerebral infarction (mTICI) 0-2a, 2b, and 3. We compared the differences of outcomes among groups on modified Rankin Scale score at 90 days, symptomatic intracerebral hemorrhage within 72 hours, and mortality. A total of 101 patients were enrolled. Median time from onset to groin puncture was 415 minutes (interquartile range: 387-497 minutes). Favorable functional outcomes were significantly better in patients with successful recanalization than in patients with failed recanalization (mTICI 0-2a, 22.7% [5/22]; mTICI 2b, 48.0% [12/25]; and mTICI 3, 61.1% [33/54]; trend P= 0.01). Complete recanalization (mTICI 3) (odds ratio, 5.34; 95% confidence interval, 1.71-16.66; P= 0.004) was associated with good functional outcome. Mortality was different among groups at 90 days (mTICI 0-2a, 36.4% [8/22]; mTICI 2b, 0, [0/25]; P= 0.001; mTICI 0-2a, 36.4% [8/22]; mTICI 3, 9.3% [5/54]; P= 0.008; and mTICI 2b, 0, [0/25]; mTICI 3, 9.3% [5/54]; P= 0.173). There were no significant differences of symptomatic intracranial hemorrhage among groups (mTICI 0-2a, 22.7% [5/22]; mTICI 2b, 12.0% [3/25]; and mTICI 3, 9.3% [5/54]; P= 0.28). For acute anterior circulation stroke patients, who were beyond the 6-hour time window, yet with small ischemic core, complete recanalization following endovascular treatment may play the most important role on clinical outcome.