A novel score to predict successful endovascular recanalization of non-acute carotid artery occlusion

BACKGROUND: To develop and validate a novel scoring system for predicting successful endovascular recanalization in patients with non-acute symptomatic carotid artery occlusion (NASCAO). METHODS: We analyzed consecutive patients from a nationwide prospective registry who underwent endovascular treatment for NASCAO. Patients were divided into derivation and validation cohorts based on the enrolling centers. Technical success was defined as Thrombolysis in Cerebral Infarction score 3 and <50% residual stenosis. A NASCAO score was developed using stepwise logistic regression based on the Bayesian information criterion. The performance of the score was examined in terms of discrimination and calibration. RESULTS: Among the 511 included patients, successful recanalization was achieved in 61.3% (192/313) of the derivation cohort and 54.5% (108/198) of the validation cohort. Four independent predictors of technical success were used to construct a 6-point NASCAO score: ischemic stroke (1 point), time from last event to intervention within 1-30 days (1 point), tapered proximal stump (1 point), and number of occluded segments (1-2: 3 points, 3-4: 2 points, 5-7: 0 points). The area under the receiver operating curve (AUC) of the NASCAO score was 0.780 (95% CI 0.729 to 0.832) in the derivation cohort and 0.758 (95% CI 0.692 to 0.824) in the validation cohort. Patients with a score of 4-6 had 6.3 times higher odds of successful recanalization than those with a score of 0-3 (95% CI 4.29 to 9.38, P<0.001). CONCLUSIONS: The NASCAO score is a reliable tool for predicting successful endovascular recanalization in patients with NASCAO.