Abstract DP258: Identifying High-Risk CVT Patients for Early Intervention: External Validation of the CLOTS-EVT Score

Background: Cerebral venous thrombosis (CVT) presents with diverse clinical features, making early recognition of patients at risk for deterioration challenging. The CLOTS-EVT score, a ten-point tool including decreased consciousness (C), low platelets and sodium (L), absence of oral contraceptive use (O), thrombosis burden of more than 3 sinuses (T), seizure (S), and papilledema (E), was developed to predict early deterioration and guide timely venous thrombectomy (VT). We aimed to externally validate this score. Methods: We retrospectively analyzed adults with cerebral venous thrombosis (CVT) treated between 2015 and 2017 across 12 centers. Clinical, laboratory, and imaging data were collected, and the CLOTS-EVT score was applied to each patient. Predictive performance was evaluated using sensitivity, specificity, predictive values, and the area under the receiver operating characteristic curve (AUC). Correlation with functional outcome at discharge and hospital length of stay were also assessed. Results: Eighty patients were analyzed (median age 38.5 years, 66% female). Headache was the most common symptom; oral contraceptive use was reported in two-thirds of women. Additional risk factors included pregnancy-related events (7.5%), central nervous system infection (1.25%), malignancy (6.25%), hereditary thrombophilia (3.75%), and smoking (15%). The transverse and sigmoid sinuses were most frequently involved. Anticoagulation was initiated in nearly all patients; 10% underwent endovascular therapy. Overall, 63.8% achieved favorable outcomes, 80% were discharged home, and mortality was 3.8%. In this cohort, 41.3% had decreased consciousness, 47.5% had a sodium level below 139 mEq/L, 38.8% had a platelet count below 225,000/μL, 31.3% were not using oral contraceptives, 25% had thrombosis in more than 3 sinuses, 20% experienced seizures, and 22.5% had papilledema. A CLOTS-EVT score ≥4 predicted early deterioration with 82% sensitivity, 61% specificity, and AUC 0.718 Figure 1. Higher scores correlated with longer hospital stay (r = 0.325) and worse functional outcome at discharge (r = 0.363). Conclusions: The CLOTS-EVT score demonstrated acceptable performance as a predictor of early deterioration in CVT within this external validation cohort. By combining standard clinical, laboratory, and imaging variables, it provides a practical tool for risk stratification and may inform consideration of venous thrombectomy alongside anticoagulation.