Impact of Asymptomatic Intracranial Hemorrhage on Outcome After Endovascular Stroke Treatment

BACKGROUND: Endovascular treatment (EVT) achieves high rates of recanalization in acute large-vessel occlusion (LVO) stroke, but functional recovery remains heterogeneous. While symptomatic intracranial hemorrhage (sICH) has been well studied, the prognostic impact of asymptomatic intracranial hemorrhage (aICH) after EVT is less certain. METHODS: We performed a pooled analysis of individual patient data from three randomized clinical trials (DEVT, RESCUE BT, MARVEL). Patients with anterior circulation LVO treated with EVT within 24 h were included. Hemorrhagic events were adjudicated by a blinded core laboratory using the modified Heidelberg Bleeding Classification. The primary outcome was 90-day modified Rankin Scale (mRS) distribution. Analyses included multivariable ordinal logistic regression, propensity score matching (PSM), and inverse probability of treatment weighting (IPTW). Exploratory analyses used LASSO-based selection to develop a risk model for a composite endpoint of aICH with poor outcome (mRS ≥ 4). RESULTS: Among 2562 eligible patients, 721 (28.1%) developed aICH, the median age was 68 years (IQR, 58-76), and 57% were women. aICH was significantly associated with worse functional outcomes (adjusted odds ratio, 0.51; 95% CI, 0.44-0.60) and higher mortality (adjusted odds ratio, 1.64; 95% CI, 1.28-2.0). These associations were consistent across analytic methods and subgroups. Parenchymal hematoma carried the greatest prognostic burden. Older age, higher baseline NIHSS scores, lower baseline ASPECTS, elevated admission glucose, and unsuccessful reperfusion are independently associated with aICH combined with poor prognosis. CONCLUSIONS: AICH after EVT is independently associated with poorer functional recovery and higher mortality, highlighting its clinical significance beyond radiological detection. TRIAL REGISTRATION: ChiCTR.org.cn Identifier: ChiCTR-IOR-17013568; ChiCTR-IOR-17014167; ChiCTR2100051729.