IMS III and MR CLEAN pooled analysis validates endovascular therapy for severe ischaemic stroke

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To conduct the analysis, investigators from both trials assessed the effect of endovascular treatment in acute ischaemic stroke patients with severe neurological deficit (National Institutes of Health Stroke Scale [NIHSS] score, ≥20) after a prespecified analysis plan.


The pooled analysis of the IMS III (Interventional management of stroke III) and MR CLEAN (Multicentre randomized clinical trial of endovascular therapy for acute ischemic stroke in the Netherlands) trials included participants with an NIHSS score of ≥20 before intravenous tissue-type plasminogen activator (tPA) treatment (IMS III) or randomisation (MR CLEAN) who were treated with intravenous tPA ≤3 hours of stroke onset.


“Our hypothesis was that participants with severe stroke randomised to endovascular therapy after intravenous tPA would have improved 90-day outcome (distribution of modified Rankin Scale scores), when compared with those who received intravenous tPA alone,” the investigators write.


Joseph Broderick and Olvert Berkhemer et al report that among 342 participants in the pooled analysis (194 from IMS III and 148 from MR CLEAN), an ordinal logistic regression model showed that the endovascular group had superior 90-day outcome compared with the intravenous tPA group (adjusted odds ratio, 1.78; 95% confidence interval, 1.20–2.66). “In the logistic regression model of the dichotomous outcome (modified Rankin Scale score, 0–2, or functional independence), the endovascular group had superior outcomes (adjusted odds ratio, 1.97; 95% confidence interval, 1.09–3.56). Functional independence (modified Rankin Scale score, ≤2) at 90 days was 25% in the endovascular group when compared with 14% in the intravenous tPA group,” they found.


This pooled analysis of data from two of the largest endovascular therapy for stroke trials demonstrates that endovascular therapy is effective and safe for patients with severe ischaemic stroke after intravenous tPA within three hours of symptom onset.