Supplementary Material for: Functional Outcome After Primary Endovascular Therapy or IV Thrombolysis Alone for Stroke. An Observational, Comparative Effectiveness Study

<b><i>Background:</i></b> Among the acute ischemic stroke patients with large vessel occlusions and contraindications for the use of IV thrombolysis, mainly on oral anticoagulation or presenting too late, primary endovascular therapy is often performed as an alternative to the standard therapy even though evidence supporting the use of endovascular reperfusion therapies is not yet established. Using different statistical approaches, we compared the functional independence rates at 3 months among patients undergoing primary endovascular therapy and patients treated only with IV thrombolysis. <b><i>Methods:</i></b> We used data from a prospective, government-mandated and externally audited registry of reperfusion therapies for ischemic stroke (January 2011 to November 2012). Patients were selected if treated with either IV thrombolysis alone (n = 1,582) or primary endovascular thrombectomy (n = 250). A series of exclusions were made to homogenize the clinical characteristics among the two groups. We then carried out multivariate logistic regression and propensity score matching analyses on the final study sample (n = 1,179) to compare functional independence at 3 months, as measured by the modified Rankin scale scores 0-2, between the two groups. <b><i>Results:</i></b> The unadjusted likelihood of good outcome was poorer among the endovascular group (OR: 0.69; 95% CI: 0.47-1.0). After adjustment, no differences by treatment modality were seen (OR: 1.51; 95% CI: 0.93-2.43 for primary endovascular therapy). Patients undergoing endovascular thrombectomy within 180-270 min (OR: 2.89; 95% CI: 1.17-7.15) and patients with severe strokes (OR: 1.84; 95% CI: 1.02-3.35) did better than their intravenous thrombolysis counterparts. The propensity score-matched analyses with and without adjustment by additional covariates showed that endovascular thrombectomy was as effective as intravenous thrombolysis alone in achieving functional independence (OR for unadjusted propensity score matched: 1.35; 95% CI: 0.9-2.02, OR for adjusted propensity score matched: 1.45; 95% CI: 0.91-2.32). <b><i>Conclusion:</i></b> This comparative effectiveness study shows that in ischemic stroke patients with contraindications for IV thrombolysis, primary endovascular treatment might be an alternative therapy at least as effective as IV thrombolysis alone. Randomized controlled trials are urgently needed.

<b><i>背景：</i></b> 对于存在静脉溶栓（intravenous thrombolysis，IV）禁忌证的大血管闭塞型急性缺血性卒中患者——主要包括正在接受口服抗凝治疗或就诊时间过晚的患者——临床常将原发性血管内治疗（primary endovascular therapy）作为标准治疗的替代方案，尽管目前尚无确凿证据支持血管内再灌注治疗（endovascular reperfusion therapies）的应用价值。本研究采用多种统计方法，对比了接受原发性血管内治疗患者与仅接受静脉溶栓患者的3个月功能独立率。
<b><i>方法：</i></b> 本研究使用2011年1月至2012年11月的前瞻性、政府强制要求且经外部审核的缺血性卒中再灌注治疗登记数据库数据。研究对象筛选标准为：仅接受静脉溶栓治疗（n=1582）或原发性血管内取栓术（n=250）。为均衡两组临床特征，我们实施了一系列排除流程。最终纳入1179例患者的研究样本后，采用多因素logistic回归（multivariate logistic regression）与倾向得分匹配（propensity score matching）分析，对比两组患者3个月时以改良Rankin量表（modified Rankin scale）评分0-2分定义的功能独立情况。
<b><i>结果：</i></b> 未校正分析显示，血管内治疗组的良好预后概率更低（比值比（odds ratio，OR）=0.69；95%置信区间（confidence interval，CI）：0.47~1.0）。经校正后，不同治疗方式间未观察到显著差异（原发性血管内治疗的OR=1.51；95%CI：0.93~2.43）。其中，发病至治疗时间处于180~270分钟区间的血管内取栓患者（OR=2.89；95%CI：1.17~7.15）与重症卒中患者（OR=1.84；95%CI：1.02~3.35）的预后优于其对应的静脉溶栓对照队列。无论是否额外校正协变量的倾向得分匹配分析均显示，原发性血管内取栓术在实现功能独立方面与单纯静脉溶栓疗效相当（未校正倾向得分匹配OR=1.35；95%CI：0.9~2.02；校正倾向得分匹配OR=1.45；95%CI：0.91~2.32）。
<b><i>结论：</i></b> 本项比较有效性研究表明，对于存在静脉溶栓禁忌证的缺血性卒中患者，原发性血管内治疗或许可作为替代疗法，其疗效至少不劣于单纯静脉溶栓。目前亟需开展随机对照试验（randomized controlled trials，RCT）以验证该结论。