Abstract A088: Outcomes of ICAS-LVO Stratified by the Severity of Stenosis: A Multicentric Inverse Probability Weighting of Treatment Analysis.

Introduction: Intracranial atherosclerotic stenosis–related large vessel occlusion (ICAS-LVO) presents unique therapeutic challenges during mechanical thrombectomy (MT). The role of adjunctive stenting and the prognostic influence of stenosis severity remain unclear. Methods: We analyzed patients with angiographically confirmed ICAS-LVO from a RESCUE-ICAS registry. Patients were stratified into moderate (50–69%) and severe (70–99%) stenosis. Outcomes were compared between stent-assisted MT and MT-alone cohorts. Inverse probability weighting of treatment (IPWT) was applied to adjust for baseline differences, including age, sex, race, hypertension, hyperlipidemia, smoking history, IV tPA use, admission NIHSS, occlusion location, and baseline ASPECT score. Primary outcome was good functional recovery (mRS 0–2 at 90 days). Secondary outcomes included mortality, procedural complications, Final recanalization and re-occlusion. Results: The study included 361 patients: 135 with moderate stenosis (59 stented, 76 non-stented) and 226 with severe stenosis (114 stented, 112 non-stented). Median age was similar across groups (~67–68 years). Female representation ranged from 36–45%. Hypertension was highly prevalent (>75%), while hyperlipidemia was more frequent in severe stenosis with stenting (61.4% vs. 40.2%, p =0.012). Median admission NIHSS was 13–15 across groups. Good CTA collaterals were present in ~53% of moderate and 60–69% of severe stenosis cases. Reocclusion occurred more frequently in the stenting groups, particularly in severe stenosis (17.5% vs. 4.5%, p =0.012). Symptomatic ICH remained low (6–10%) across groups. In the moderate stenosis cohort, stenting showed a nonsignificant trend toward improved functional outcomes (47.5% vs. 32.9%, IPWT-adjusted OR 1.62, 95% CI 0.91–2.89, p =0.104) and reduced mortality (16.9% vs. 30.3%, p =0.072). In contrast, patients with severe stenosis derived clearer benefit, with higher rates of good outcome (37.7% vs. 20.5%, p =0.012), despite increased reocclusion risk. Conclusion: In this large, multicenter ICAS-LVO cohort, outcomes differed by stenosis severity. Stenting conferred no significant advantage in moderate stenosis in achieving indepdence at 90 days. In severe stenosis (70–99%), however, stenting was associated with higher rates of functional independence despite higher reocclusion. These findings highlight stenosis severity as a key determinant when considering stenting during thrombectomy.