Abstract TMP108: External Validation of the SI 2 NCAL 2 C Score for Mortality Following Cerebral Venous Thrombosis

Background: Prognostication following cerebral venous thrombosis (CVT) remains challenging. Mortality is an uncommon yet catastrophic outcome after CVT. We sought to externally validate the SI 2 NCAL 2 C score for mortality in an international cohort. Methods: The SI 2 NCAL 2 C score was developed from the International CVT Consortium Registry to predict mortality by 30 days and one year using the factors: female- s ex-specific risk factors, i ntracerebral hemorrhage, CNS i nfection, n eurological focal deficits, c oma, a ge, hemoglobin l evel, glucose l evel, and c ancer. ACTION-CVT was an international retrospective study that enrolled consecutive patients with CVT across 27 centers. Model performance was evaluated using the area under the curve (AUC) of the time-dependent receiver operating characteristic curve and calibration plots. Missing data were imputed using the additive regression and predictive mean matching methods. Bootstrapping was performed with 1000 iterations. Results: After exclusion of one site which contributed data to the derivation cohort, 950 of 1,025 patients enrolled in ACTION-CVT were analyzed. Compared to the derivation cohort, the ACTION-CVT cohort was older (median 44 vs 40 years), less female (63.4% vs 69.8%), and with milder clinical presentation (focal deficits 38.6% vs 57.1%; seizures 22.6% vs 36.7%). Mortality was 2.5% by 30 days and 6.0% by one year. The SI 2 NCAL 2 C score achieved an AUC of 0.716 [95% CI 0.603-0.823] for mortality by 30 days and 0.820 [0.761-0.878] for mortality by one year. Calibration plots demonstrated an overestimation of predicted risk among patients with low observed mortality, concordant with score derivation (Fig 1, A-D). Conclusions: The SI 2 NCAL 2 C score had acceptable performance in an international validation cohort despite differences in baseline characteristics between cohorts. The SI 2 NCAL 2 C score warrants additional validation studies in diverse populations and clinical implementation studies.