Risk scoring system to predict 3-year survival in patients treated for asymptomatic carotid stenosis

Objective To identify risk factors and stratify their effect of compromising 3-year survival in patients treated for asymptomatic carotid disease based upon recently updated guidelines from the Society for Vascular Surgery. Methods Outcomes of 506 patients who underwent carotid intervention for asymptomatic carotid disease (1999-2008) were analyzed. Hospital computerized medical records were reviewed. When local records were sparse, Social Security Death Index was queried to confirm mortality. Following multivariable Cox regression analysis, a score was assigned based on the calculated hazard ratio (HR) in the following fashion: HR 1.5-1.9 = 1 point; HR 2.0-3.0 = 2 points; and HR >3 = 3 points. The sum of those points comprised the final score for each patient. Kaplan-Meier analyses were then performed to delineate survival differences. Results Seventy patients (13.83%) did not survive beyond 3 years after the procedure. Age >80 years (HR, 1.79; P = .05; score 1), diabetes mellitus (HR, 1.99; P < .05; score 1), coronary artery intervention (HR, 2.03; P < .01; score 2), severe chronic kidney disease defined as glomerular filtration rate 2 was associated with 31.6% 3-year mortality (HR, 6.10; P < .001). The score value was not associated with the stroke rate at any time point. The resultant score was validated in a separate population of patients with symptomatic carotid disease. Conclusions This easy predictive score underscores the association of medical risk factors with decreased 3-year survival. This finding may impact future clinical decisions for management of asymptomatic carotid disease.