Research progress on the prediction of futile recanalization following endovascular treatment for acute ischemic stroke

Research progress on the prediction of futile recanalization following endovascular treatment for acute ischemic strokeTo the Editor, Endovascular treatment(EVT) is an important reperfusion strategy for acute ischemic stroke (AIS) caused by large vessel occlusion.However, despite successful vascular recanalization, a subset of patients still experiences unfavorable outcomes, a phenomenon known as futile recanalization.Futile recanalization is defined as successful vascular recanalization achieving a modified Thrombolysis in Cerebral Infarction (mTICI) grade of 2b/3 following EVT, accompanied by unfavorable 90-day neurological functional outcome (modified Rankin Scale [mRS] score 3-6).Current studies indicate that its incidence ranges from 32.4% to 56.7% 1 The mechanisms underlying futile recanalization primarily involve the following conditions.(1) Ischemia-reperfusion injury: Following ischemic brain injury, blood-brain barrier permeability increases, and fluid extravasation induces vasogenic cerebral edema.This elevates interstitial pressure and compresses microvessels, leading to irreversible tissue damage and preventing the restoration of cerebral perfusion.(2) No-reflow phenomenon: Microcirculatory dysfunction, arising from infarct core injury, delayed treatment, vasospasm, endothelial swelling, capillary compression, distal vessel embolization, and persistent pericyte contraction followed by cell death, can subsequently precipitate the no-reflow phenomenon.(3) Failed salvage of the ischemic penumbra and disruption of brain networks: Prolonged ischemia and hypoxia in neuronal cells disrupt the functional connectivity of global brain networks.Specifically, structural disruption of white matter tracts impairs cerebral function, ultimately resulting in futile recanalization.(4) Complications of EVT including mitochondrial dysfunction, secondary occlusion due to thrombus fragmentation, and hemorrhagic transformation also contribute to the pathological process of futile recanalization.Current predictive models are categorized into four types: clinical baseline risk factors imaging predictors, traditional predictive scoring models, and artificial intelligence (AI) models.( 1) Clinical baseline risk factors include advanced age, high baseline National Institutes of Health Stroke Scale (NIHSS) score, underlying diseases such as hypertension, diabetes mellitus, and atrial fibrillation, as well as prolonged onset-to-reperfusion time(OTR).(2)Imaging predictive factors encompass large infarct core volume, decreased ASPECTS score, poor collateral circulation, and moderate-to-severe white matter lesions.However, the predictive value of a single indicator is limited and lacks a unified cutoff value.(3) Among traditional clinical scores, 2 the HIAT and THRIVE scores do not account for vascular recanalization status and can only indirectly indicate poor prognosis.The SNAP and Gan scores 3 are specifically designed for patients with large core infarcts; the CHANOA score 4