Background: Recent randomized clinical trials (RCTs) using stent-retriever thrombectomy demonstrated clear and consistent benefit of endovascular recanalization therapy (ERT) in contrast to the negative result of earlier trials. We aimed to calculate the pooled estimate of the ERT benefit added to standard therapy in AIS.
Methods: We systematically searched Pubmed and EMBASE until 31 Apr 2015. Inclusion criteria were 1) RCT, 2) the active arm receiving ERT, 3) the control arm receiving standard therapy including intravenous TPA, but not treated with ERT, and 4) mRS score reported at 90 days or at the end of the trial. Using a random-effect model, we generated a pooled estimate as an odds ratio (OR) with 95% CI for the effect of ERT regarding the efficacy and safety outcomes for all trials, stent-retriever trials, and RCTs comparing ERT and intravenous TPA.
Results: We identified 15 relevant RCTs involving 2,899 patients. For all trials, ERT compared to control was associated with increased good outcome (OR [95% CI], 1.79 [1.34, 2.40]; P<0.0001; number needed-to-treat [NNT]=9). ERT also increased outcomes of no or minimal disability, good neurological recovery, good activity of daily living, and recanalization. ERT was not associated with increased risks of symptomatic intracranial hemorrhage (SICH) (1.19 [0.83, 1.69]; P=0.3453; number needed-to-harm [NNH]=88) and death (0.87 [0.71, 1.05]; P=0.1508; NNT=55). On the contrary, ERT significantly reduced extreme disability or death (0.77 [0.61, 0.97]; P=0.0246; NNT=21). When restricting 5 stent-retriever RCTs which generally compared ERT added to intravenous TPA versus intravenous TPA alone, the benefit was even greater: 2.39 [1.88, 3.04], P<0.0001, NNT=5 for good outcome; 0.57 [0.41, 0.78], P=0.0006, NNT=9 for extreme disability or death. Analysis restricting 8 RCTs comparing ERT (added to intravenous TPA in 6 RCTs) with intravenous TPA alone also showed similar efficacy and safety.
Conclusions: This updated meta-analysis shows that ERT compared to the current standard therapy substantially improves good outcome and reduces extreme disability or death without significantly increasing SICH. Now, we are facing a new challenge how to provide ERT more and faster to eligible patients.