Safety and effectiveness of endovascular treatment after 6 hours of symptom onset in patients with anterior circulation ischemic stroke: a matched case control study.

BACKGROUND: Endovascular treatment within 6 hours of symptom onset appears to be beneficial in carefully selected patients with ischemic stroke. It is unclear whether endovascular treatment beyond 6 hours of symptom onset is safe and efficacious.

METHODS: Over a 6-year period, 52 patients with acute ischemic stroke in the anterior circulation underwent emergent endovascular thrombolytic infusion and mechanical thrombectomy after 6 hours of symptom onset at 3 institutions. Their outcomes were compared to 52 placebo-treated patients matched by baseline National Institutes of Health Stroke Scale (NIHSS) score and nonlacunar anterior circulation location from the Trial of Org 10172 in Acute Stroke Treatment trial using a 1:1 ratio. Univariate and multivariate analyses were performed comparing the rates of symptomatic intracerebral hemorrhage, early neurologic improvement, favorable outcome at 7 days or discharge, and in-hospital mortality between the 2 groups.

RESULTS: After adjustment for gender, time interval between symptom onset to treatment, hypertension, hyperlipidemia, and history of cigarette smoking, rates of neurologic improvement at 24 hours (odds ratio [OR] 1.15; 95% confidence interval [CI] 0.43-3.1) and favorable outcome at 7 days or discharge (OR 1.39; 95% CI 0.47-4.05) were similar in the 2 groups. No differences in the rates of symptomatic intracerebral hemorrhage or death were found after adjusting for potential confounders. In an analysis limited to only those patients who underwent computed tomographic perfusion or magnetic resonance imaging before receiving endovascular treatment, the rate of favorable outcome at 7 days or discharge was similar between patients who underwent endovascular treatment and control patients (35.7% v 32.1%; P = .77).

CONCLUSIONS: We did not observe any evidence of benefit in halting neurologic worsening or improving outcomes among patients undergoing endovascular treatment for treatment of an anterior circulation ischemic stroke after 6 hours of symptom onset. Strong evidence of both the safety and efficacy of emergent endovascular treatment when administered to patients with stroke in the anterior circulation is needed.