[Current Evidence of Mechanical Thrombectomy for Acute Cerebral Artery Occlusion]

Following previous negative randomized controlled trials (RCTs), the validity of mechanical thrombectomy (MT) for large-vessel occlusion (LVO) of the anterior circulation was established by multiple positive RCTs in 2015. The success of these RCTs was achieved by introducing a stent retriever, which enabled a safer procedure and higher revascularization rate. Since then, novel evidence has been accumulated by several emerging RCTs to expand the indication of MT. First, the time limit for MT was extended based on RCTs demonstrating the efficacy of MT in patients with a longer penumbra on radiological imaging. Thus, rescuing patients with a larger ischemic core using MT has been justified by RCTs revealing sufficient functional recovery and acceptable hemorrhagic complications in this subgroup. Basilar artery occlusion, which has a poor prognosis under conservative treatment, was also approved as a good candidate for MT. However, evidence of MT for medium vessel occlusion or less severe neurological deficits remains unelucidated, presumably due to a relatively better natural history and non-negligible hemorrhagic complications. Further evidence-based expansion of MT indications is anticipated, although the application of novel evidence to real-world treatments remains a concern.