The utility of selective screening for carotid stenosis in cardiac surgery patients

PURPOSE: To determine if any of 8 categorical clinical variables can be used to select patients and improve the yield of a screening program for severe carotid stenosis (> or = 80%) in elective cardiac surgery patients. METHODS: A prospective cohort analysis of 200 consecutive patients prior to elective cardiac surgery for the following variables: age, gender, smoking carotid bruit, peripheral vascular disease, hyperlipidaemia, previous neurologic symptoms and diabetes mellitus. All patients were subsequently screened with carotid duplex scanning for the presence of severe carotid stenosis. Positive scans were confirmed by angiography. RESULTS: Sixteen patients (8%) were identified with severe carotid stenosis. Univariate analysis identified three variables that increase risk for carotid stenosis: carotid bruit (relative risk (RR)=16.4, 5.4-57.6 95% confidence interval, p<0.001), neurological history (RR=10.3, 3.9-23.2, p<0.001) and peripheral vascular disease (RR=5.3, 1.9-14.9, p<0.001). Stepwise logistic regression analysis identified previous neurologic history and carotid bruit as independent predictors of stenosis. If screening for carotid stenosis was limited to patients with these two variables, then 37 (18.5% of total) patients would have been screened. Fourteen of these 37 (37.8%) had a severe carotid stenosis. Two patients with stenosis (12.5% of those with carotid stenosis, 1% of total patient population) would not have been screened. CONCLUSIONS: Clinical variables can be used to improve the yield of a preoperative screening program for carotid stenosis.