Mechanical thrombectomy with retrievable stents and aspiration catheters for acute ischaemic stroke: a metaanalysis of randomised controlled trials

Background: Retrievable stents and aspiration catheters have been developed to provide more effective arterial recanalisation in acute ischaemic stroke. Aims: The aim of this analysis was to test the effect of mechanical thrombectomy on mortality and long-term neurological outcome in patients presenting with acute large-vessel anterior circulation ischaemic stroke. Methods: A structured search identified randomised controlled trials of thrombectomy (using a retrievable stent or aspiration catheter) versus control on a background of medical therapy which included intravenous thrombolysis if appropriate. The primary endpoint was disability at 90-day follow-up as assessed by the modified Rankin scale (mRS). Secondary endpoints included all-cause mortality and symptomatic intracranial haemorrhage. A Bayesian mixed-effects model was used for analysis. Results: Twelve (12) trials met the inclusion criteria, comprising a total of 1,276 patients randomised to thrombectomy and 1,282 patients to control. Randomisation to thrombectomy significantly reduced disability at 90 days (OR 0.52, 95% credible interval 0.46 to 0.61, probability(control better)<0.0001). Furthermore, thrombectomy reduced the odds of functional dependence at 90 days, indicated by an mRS score >2 (OR 0.44, CrI 0.37 to 0.52, pr<0.0001). Thrombectomy reduced all-cause mortality at 90 days (16.1% vs 19.2%, OR 0.81, 95% CrI 0.66 to 0.99, pr=0.024). The frequency of symptomatic intracranial haemorrhage was similar between thrombectomy (4.2%) and control (4.0%) (OR 1.12, 95% CrI 0.76 to 1.68, pr=0.72). Conclusions: In patients with an acute anterior circulation stroke, modern device thrombectomy significantly reduces death and subsequent disability. The magnitude of these effects suggests that universal access to this treatment strategy should be the standard of care.