Abstract DP227: Age Modifies the Prognostic Utility of Posterior Circulation ASPECTS in Vertebrobasilar Occlusion after Endovascular Therapy

Background: Endovascular thrombectomy (EVT) is the established therapy for vertebrobasilar occlusion (VBO). However, predictors of outcome remain heterogeneous, and the prognostic utility of posterior circulation ASPECTS (pc-ASPECTS), particularly in elderly patients, is not well defined. We sought to evaluate the interaction between pc-ASPECTS and age on clinical outcomes after EVT for VBO in a 10-year multicenter cohort. Methods: We retrospectively included patients with VBO treated with EVT from a prospectively maintained registry across three comprehensive stroke centers between 2014 and 2024. Patients were stratified by pc-ASPECTS (≤8 vs. >8) and by age (<80 vs. ≥80 years). Baseline demographics, procedural characteristics, and outcomes were compared. The primary outcome was functional independence (mRS 0–3) at 90 days, with mortality as a secondary outcome. Logistic regression models assessed the interaction between age and pc-ASPECTS, with adjusted odds ratios (aOR) and 95% confidence intervals (CI) reported. Results: A total of 201 patients were included (median age 69 [IQR 59–77], 23% ≥80 years), of whom 59 (29%) had pc-ASPECTS ≤8. Low-ASPECTS patients had higher rates of hypertension (84.7% vs. 69.0%, p=0.023), lower reperfusion success (mTICI 2b: 87.7% vs. 97.1%, p=0.016), and numerically worse functional outcomes (mRS 0–3: 37.3% vs. 45.1%, p=0.35). Stratified analyses revealed that in patients <80 years, higher pc-ASPECTS was associated with greater reperfusion success and improved functional outcomes (mRS 0–3: 53.3% vs. 36.7%, p=0.05). In contrast, pc-ASPECTS did not differentiate outcomes in octogenarians (21.6% vs. 40.0%, p=0.25). Interaction analysis confirmed significant effect modification by age (p-inter=0.047), with pc-ASPECTS predictive in younger but not older patients. (Table1, Table2, Table 3) Conclusion: In this multicenter cohort, pc-ASPECTS was a useful prognostic marker for EVT outcomes in younger patients with VBO but not in octogenarians, where age-related vulnerability may cancel imaging-based selection criteria. These findings suggest the need for other age-sensitive prognostic frameworks to optimize EVT decision-making in posterior circulation stroke.