Prediction of long-term mortality for patients with severe asymptomatic de novo carotid stenosis undergoing carotid endarterectomy (PREMY2SE-CEA): Derivation and validation of a novel risk score.

OBJECTIVE: The aim of the present study was to develop and validate a risk prediction model for the prediction of long-term mortality for patients with severe asymptomatic de novo carotid stenosis undergoing carotid endarterectomy (PREMY2SE-CEA). METHODS: Data were collected retrospectively from a dedicated database of consecutive patients who had undergone elective CEA for severe (>70% using the NASCET [North American Symptomatic Carotid Endarterectomy Trial] criteria) asymptomatic carotid stenosis at two Italian University Hospitals from 2008 through 2016. Internal validation of the score was performed after random sampling in a 3:1 fashion. The primary end point of the PREMY2SE-CEA risk score was the 5-year mortality. RESULTS: Of the 1214 patients, 901 were included in the derivation cohort and 313 in the validation cohort. Using multivariable logistic regression with backward elimination, a parsimonious model was derived. A risk score incorporating eight risk factors was generated and found to be highly predictive of long-term mortality in the derivation (odds ratio [OR], 1.38; 95% confidence interval [CI], 1.28-1.41; P < .001) and validation (OR, 1.29; 95% CI, 1.21-1.37; P <.001) cohorts. The discrimination power in the receiver operating characteristic curve analysis was C = 0.775 (95% CI, 0.74-.80), and the optimism-corrected area under the curve in the bootstrapped samples was 0.761 (P < .001). A strong correlation was found between the predicted and actual mortality rates in the validation cohort (r = 0.71; P < .001). CONCLUSIONS: In the present study, we have described the development, evaluation, and validation of a risk prediction model (PREMY2SE-CEA) for long-term mortality after CEA in asymptomatic patients. Physicians could use the PREMY2SE-CEA risk scoring tool to complement their estimates of life expectancy and prompt selective consideration of prophylactic CEA to improve the long-term benefits of interventions.