Abstract DP138: Composite Arterial and Venous Collateral Score on Single-Phase CTA Predicts 90-Day Outcomes in Anterior Circulation Large-Vessel Occlusion Stroke

Background: Collateral circulation influences clinical outcomes in patients with acute ischemic stroke due to anterior circulation large-vessel occlusion (LVO). While both arterial and venous collateral assessments on single-phase CTA have prognostic value, they have traditionally been evaluated independently. Purpose: We developed the CTA Collateral Impairment Score (CCIS), a composite measure incorporating arterial (Tan) and venous (COVES) scores, and investigated its association with 90-day functional outcomes. Materials and Methods: We conducted a retrospective cohort study including 1,080 patients with anterior circulation LVO stroke across four comprehensive stroke centers. Patients were assigned a CCIS of 0 (preserved), 1 (moderate impairment), or 2 (severe impairment) based on predefined thresholds for Tan and COVES scores. Results: Favorable outcomes (mRS 0–2) occurred in 66% of patients with CCIS 0, 32% with CCIS 1, and 17% with CCIS 2 (p<0.001). Mortality increased with higher CCIS (11%, 25%, and 36% for CCIS 0, 1, and 2 respectively; p<0.001). In multivariable models, CCIS 0 and 1 were independently associated with greater odds of favorable outcomes compared with CCIS 2 (adjusted OR 5.77 95% CI, 3.78–8.82 and 1.72 95% CI, 1.14–2.60, respectively). CCIS also predicted mortality (adjusted OR for CCIS 0 vs. 2: 0.39 95% CI, 0.25–0.61; p<0.001). The predictive performance of CCIS (AUC 0.73) exceeded that of ASPECTS and occlusion site and approximated NIHSS; inclusion of CCIS improved multivariable model discrimination (AUC 0.84). Conclusions: CCIS, a composite arterial and venous collateral score derived from single-phase CTA, was strongly and independently associated with 90-day outcomes in anterior circulation LVO stroke. Its integration into acute stroke imaging assessment may improve risk stratification and guide therapeutic decisions.