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%; I²=76.5%; p<0.001) and 33.2% (95% CI 28.5% to 38.3%; I²=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%; I²=64.24%; p=0.039), 35.7% (95% CI 30.5% to 41.3%; I²=23.11%; p=0.245), and 49.7% (95% CI 44.2% to 55.3%; I²=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.