Endovascular thrombectomy and intra-arterial interventions for acute ischaemic stroke

Abstract

Background: Most disabling strokes are due to a blockage of a large artery in the brain by a blood clot. Prompt removal of the clot with intra-arterial thrombolytic drugs or mechanical devices, or both, can restore blood flow before major brain damage has occurred, leading to improved recovery. However, these so-called endovascular interventions can cause bleeding in the brain. This is a review of randomised controlled trials of endovascular thrombectomy or intra-arterial thrombolysis, or both, for acute ischaemic stroke.

Objectives: To assess whether endovascular thrombectomy or intra-arterial interventions, or both, plus medical treatment are superior to medical treatment alone in people with acute ischaemic stroke.

Search methods: We searched the Trials Registers of the Cochrane Stroke Group and Cochrane Vascular Group (last searched 1 September 2020), CENTRAL (the Cochrane Library, 1 September 2020), MEDLINE (May 2010 to 1 September 2020), and Embase (May 2010 to 1 September 2020). We also searched trials registers, screened reference lists, and contacted researchers.

Selection criteria: Randomised controlled trials (RCTs) of any endovascular intervention plus medical treatment compared with medical treatment alone in people with definite ischaemic stroke.

Data collection and analysis: Two review authors (MBR and MJ) applied the inclusion criteria, extracted data, and assessed trial quality. Two review authors (MBR and HL) assessed risk of bias, and the certainty of the evidence using GRADE. We obtained both published and unpublished data if available. Our primary outcome was favourable functional outcome at the end of the scheduled follow-up period, defined as a modified Rankin Scale score of 0 to 2. Eighteen trials (i.e. all but one included trial) reported their outcome at 90 days. Secondary outcomes were death from all causes at in the acute phase and by the end of follow-up, symptomatic intracranial haemorrhage in the acute phase and by the end of follow-up, neurological status at the end of follow-up, and degree of recanalisation.

Main results: We included 19 studies with a total of 3793 participants. The majority of participants had large artery occlusion in the anterior circulation, and were treated within six hours of symptom onset with endovascular thrombectomy. Treatment increased the chance of achieving a good functional outcome, defined as a modified Rankin Scale score of 0 to 2: risk ratio (RR) 1.50 (95% confidence interval (CI) 1.37 to 1.63; 3715 participants, 18 RCTs; high-certainty evidence). Treatment also reduced the risk of death at end of follow-up: RR 0.85 (95% CI 0.75 to 0.97; 3793 participants, 19 RCTs; high-certainty evidence) without increasing the risk of symptomatic intracranial haemorrhage in the acute phase: RR 1.46 (95% CI 0.91 to 2.36; 1559 participants, 6 RCTs; high-certainty evidence) or by end of follow-up: RR 1.05 (95% CI 0.72 to 1.52; 1752 participants, 10 RCTs; high-certainty evidence); however, the wide confidence intervals preclude any firm conclusion. Neurological recovery to National Institutes of Health Stroke Scale (NIHSS) score 0 to 1 and degree of recanalisation rates were better in the treatment group: RR 2.03 (95% CI 1.21 to 3.40; 334 participants, 3 RCTs; high-certainty evidence) and RR 3.11 (95% CI 2.18 to 4.42; 268 participants, 3 RCTs; high-certainty evidence), respectively.

Authors' conclusions: In individuals with acute ischaemic stroke due to large artery occlusion in the anterior circulation, endovascular thrombectomy can increase the chance of survival with a good functional outcome without increasing the risk of intracerebral haemorrhage or death.

Trial registration: ClinicalTrials.gov NCT01717755 NCT01852201 NCT02419781 NCT03094715 NCT03805308.