Influence of ASPECTS and endovascular thrombectomy in acute ischemic stroke: a meta-analysis

Background Prompt revascularization of the ischemic penumbra following an acute ischemic event (AIS) has established benefit within the literature. However, use of the semi-quantitative Alberta Stroke Program Early CT Score (ASPECTS) to evaluate patient suitability for revascularization has been inconsistent in patient risk stratification and selection. Objective To conduct a meta-analysis to evaluate the available evidence for a clinically valid ASPECTS threshold in assessment of suitability for revascularization following AIS. Methods Two independent reviewers searched Medline (Ovid) and Cochrane Central Register of Systematic Reviews databases for studies appraising outcomes of endovascular thrombectomy (EVT) in relation to a variably-defined preoperative ASPECTS. Results A total of 13 articles were included. The pooled good outcome proportion after EVT was 41.4% (95% CI 36.4% to 46.6%; p<0.001), with subjective study-specific definitions of favorable and unfavorable subgroup outcomes of 49.7% (95% CI 44.2% to 55.3%; I-2=76.5%; p<0.001) and 33.2% (95% CI 28.5% to 38.3%; I-2=33.16%), respectively. Objective trichotomization into low (0-4), intermediate (5-7), and high (8-10) subgroups yielded pooled good outcome proportions of 17.1% (95% CI 6.8% to 36.8%; I-2=64.24%; p=0.039), 35.7% (95% CI 30.5% to 41.3%; I-2=23.11%; p=0.245), and 49.7% (95% CI 44.2% to 55.3%; I-2=76.5%; p<0.001) for low, intermediate, and high ASPECTS, respectively. Conclusions A subjectively favorable ASPECTS is associated with significantly better outcomes after EVT than an unfavorable ASPECTS, regardless of the cut-off used. EVT is unlikely to be useful in patients with an objectively low ASPECTS and is likely to be useful for those with high ASPECTS; findings in patients with intermediate ASPECTS were equivocal.