Risk scoring system to predict life expectancy after CEA in patients with asymptomatic carotid artery stenosis

Introduction: Surgical treatment of asymptomatic carotid stenosis is currently debated. Reduction of the risk of stroke is partially counterbalanced by perioperative events. Therefore, recent guidelines recommend exclusion of patients without a minimum life-expectancy of 3-5 years. Purpose of this study is to identify factors associated with a higher mortality during long-term follow-up after carotid endarterectomy (CEA). Subsequently to design a scoring system for stratifying the expected survival of candidates to CEA, based on each patient’s risk factors. Methods: From 2002 to 2013, 648 asymptomatic patients underwent CEA. Data on preoperative comorbidities and postoperative complications were extrapolated and converted to dichotomous variables. Hazard Ratios (HR) were calculated for each risk factor using Cox regression models. We assigned to each risk factor a score based on the weight of their beta coefficients in a uni-variate analysis using the lowest value as reference. For each patient we calculated total risk score as the sum of all risk factors. Kaplan-Meyer’s survival curves were designed after grouping patients according to their level of preoperative risk, based on their individual risk score. Results: 42 males (66%) and 219 females (34%) with a mean age of 74 years (range 47-93) were operated in the study period. Combined 30-days postoperative stroke/death rate was 1.23%. Patients were followed for a median of 56 months (IQR 27-84). 5-years survival was 84%. The following coefficients were assigned to factors that negatively influenced life-expectancy after surgical procedure: 8 points to dialysis (HR 7.74) P=.005 and age ≥80 (HR 7.43; P=.0001) 4 points to Creatinine ≥1.5 mg/dL (HR 3.03; P=.0001) and age 70-79 (HR 3.22; P=.004) 1 point to COPD (HR 1.42; P=.23) lack of statins on treatment (HR 1.55; P=.08) any therapy for diabetes mellitus (HR 1.36; P=.17 and CAD (past MI or coronary intervention) (HR 1.30; P=.34) 5-years survival rate was 97% for patients with score 0-3, 89% for score 4-8, 79% for score 9-12, and 66% for score 12-16 (P<0.0001). Conclusion: In our experience with asymptomatic CEA, we report a low rate of perioperative events and a high proportion of patients surviving more than 5 years after the procedure, in accordance with current literature. Our scoring system is a simple clinical tool for prediction of post-operative life expectancy that could be easily implemented to conventional perioperative risk assessment for selection of asymptomatic patients who would benefit from CEA.