AURORA: Evidence in favour of thrombectomy beyond six hours strengthened by meta-analysis

aurora meta-analysis
Tudor Jovin (L), Raul Nogueira (R)

Evidence favouring endovascular therapy (EVT) in anterior circulation stroke patients presenting with reversible cerebral ischaemia in the later time window (beyond six hours) from time last known well has been strengthened by a recent systematic review and individual patient data meta-analysis. These findings are published in The Lancet by leading stroke neurologists Tudor Jovin (Cooper University Health Care, Camden, USA) and Raul Nogueira (University of Pittsburgh Medical Center [UPMC] Stroke Institute, Pittsburgh, USA), and colleagues.

In their report, the researchers note that trials examining the benefit of EVT via thrombectomy in anterior circulation proximal large vessel occlusion (LVO) stroke have enrolled patients considered to have salvageable brain tissue, who were randomly assigned beyond six hours and—depending on study protocol—up to 24 hours from time last seen well.

As such, they aimed to estimate the benefit of thrombectomy overall, and in prespecified subgroups, through a systematic review and an individual patient data meta-analysis of randomised controlled trials (RCTs) involving endovascular stroke therapy between January 2010 and March 2021.

In this research—the Analysis of pooled data from randomized studies of thrombectomy more than six hours after last known well (AURORA) collaboration—the primary outcome was disability on the modified Rankin Scale (mRS) at 90 days, analysed by ordinal logistic regression. Key safety outcomes were symptomatic intracerebral haemorrhage and mortality within 90 days, the researchers add.

Data from 505 patients, 266 of whom were in intervention groups and 239 of whom were in control groups, were included from a total six trials that met the review’s inclusion criteria. The mean age of these patients was 68.6 years, and 259 were women (51.3%).

Primary outcome analysis showed a benefit of thrombectomy with an unadjusted common odds ratio (OR) of 2.42 (95% confidence interval [CI], 1.76–3.33; p<0.0001) and an adjusted common OR—for age, gender, baseline stroke severity, extent of infarction on baseline head computed tomography (CT), and time from onset to random assignment—of 2.54 (1.83–3.54; p<0.0001). Thrombectomy was associated with higher rates of independence in activities of daily living (mRS score of 0–2) than best medical therapy alone, with 122 of 266 patients (45.9%) achieving this outcome in the former group, and 46 of 238 patients (19.3%) achieving it in the latter (p<0.0001).

No significant difference between intervention and control groups was found when analysing either 90-day mortality or symptomatic intracerebral haemorrhage, the researchers also note. No heterogeneity of treatment effect was noted across subgroups defined by age, gender, baseline stroke severity, vessel occlusion site, baseline Alberta Stroke Program Early CT Score (ASPECTS), and mode of presentation. However, treatment effect was stronger in patients randomly assigned within 12–24 hours (common OR=5.86 [95% CI, 3.14–10.94]) when compared to those randomly assigned within six–12 hours (1.76 [1.18–2.62]; p=0.0087).

“These findings strengthen the evidence for benefit of endovascular thrombectomy in patients with evidence of reversible cerebral ischaemia across the six–24-hour time window and are relevant to clinical practice,” Jovin, Nogueira et al conclude. “Our findings suggest that, in these patients, thrombectomy should not be withheld on the basis of mode of presentation or of the point in time of presentation within the six–24-hour time window.”


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