BACKGROUND The effect of endovascular thrombectomy that is performed more than 6 hours after the onset of ischemic stroke is uncertain. Patients with a clinical deficit that is disproportionately severe relative to the infarct volume may benefit from late thrombectomy. METHODS We enrolled patients with occlusion of the intracranial internal carotid artery or proximal middle cerebral artery who had last been known to be well 6 to 24 hours earlier and who had a mismatch between the severity of the clinical deficit and the infarct volume, with mismatch criteria defined according to age (<80 years or ≥80 years). Patients were randomly assigned to thrombectomy plus standard care (the thrombectomy group) or to standard care alone (the control group). The coprimary end points were the mean score for disability on the utility-weighted modified Rankin scale (which ranges from 0 [death] to 10 [no symptoms or disability]) and the rate of functional independence (a score of 0, 1, or 2 on the modified Rankin scale, which ranges from 0 to 6, with higher scores indicating more severe disability) at 90 days. RESULTS A total of 206 patients were enrolled; 107 were assigned to the thrombectomy group and 99 to the control group. At 31 months, enrollment in the trial was stopped because of the results of a prespecified interim analysis. The mean score on the utility-weighted modified Rankin scale at 90 days was 5.5 in the thrombectomy group as compared with 3.4 in the control group (adjusted difference [Bayesian analysis], 2.0 points; 95% credible interval, 1.1 to 3.0; posterior probability of superiority, >0.999), and the rate of functional independence at 90 days was 49% in the thrombectomy group as compared with 13% in the control group (adjusted difference, 33 percentage points; 95% credible interval, 24 to 44; posterior probability of superiority, >0.999). The rate of symptomatic intracranial hemorrhage did not differ significantly between the two groups (6% in the thrombectomy group and 3% in the control group, P=0.50), nor did 90-day mortality (19% and 18%, respectively; P=1.00). CONCLUSIONS Among patients with acute stroke who had last been known to be well 6 to 24 hours earlier and who had a mismatch between clinical deficit and infarct, outcomes for disability at 90 days were better with thrombectomy plus standard care than with standard care alone. (Funded by Stryker Neurovascular; DAWN ClinicalTrials.gov number, NCT02142283 .).

中文翻译：

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卒中后6至24小时进行血栓切除术，缺乏与梗死之间不匹配。

背景技术在缺血性中风发作后超过6小时进行的血管内血栓切除术的效果尚不确定。相对于梗塞体积严重程度严重的临床缺陷患者可从晚期血栓切除术中受益。方法我们招募了最后一次已知早于6至24小时并且临床缺陷严重程度与梗死体积之间不匹配且符合不匹配标准的颅内颈内动脉或近端中脑动脉闭塞的患者根据年龄（<80岁或≥80岁）定义。患者被随机分配至血栓切除术加标准治疗（血栓切除术组）或单独接受标准治疗（对照组）。主要共同终点是实用加权加权兰金量表（范围从0 [死亡]到10 [无症状或残疾]）的平均残疾评分和功能独立率（0、1或0）。在改良的Rankin量表上为2，范围为0到6，得分越高，表示在90天时有更严重的残疾。结果共纳入206例患者。血栓切除术组107例，对照组99例。在31个月时，由于预先确定的中期分析结果，该试验被停止了。血栓切除术组在90天时的效用加权改良兰金评分平均得分为5.5，而对照组为3.4（校正差异[贝叶斯分析]为2.0分；可信区间为95％，为1.1至3.0；后验概率优越 > 0.999），血栓切除术组在90天时的功能独立性率为49％，而对照组为13％（调整后的差异为33个百分点；可信区间为95％，介于24到44之间；优越性在后方，> 0.999）。两组的症状性颅内出血发生率无显着差异（血栓切除术组为6％，对照组为3％，P = 0.50），90天死亡率也无显着差异（分别为19％和18％； P = 1.00）。结论在最后一次已知于6至24小时之前且临床缺陷与梗塞之间不匹配的急性中风患者中，血栓切除术加标准治疗比仅使用标准治疗更好地改善了90天的残疾结果。（由Stryker Neurovascular资助； DAWN ClinicalTrials.gov编号，NCT02142283。）。