SCREENING FOR CAROTID AND RENAL-ARTERY STENOSES IN PATIENTS WITH AORTOILIAC DISEASE

Patients with severe stenoses of the carotid and renal arteries define a population at high risk but most of them are asymptomatic. Here ari ses the question of who must be tested and what would be the actual ut ility of a screening program in the general or selected populations. T he aim of this study was to assess the efficacy of a duplex-based scre ening for carotid and renal arteries stenoses, in a subset of patients with aortoiliac arterial disease, in terms of: (1) prevalence of occl usive disease of the carotid and renal arteries detected and surgical procedures generated; (2) analysis of clinical variables that could be useful to increase the suspicion index for the disease; and (3) predi ctive values of duplex scanning adjusted for the observed prevalence. One hundred sixty eight consecutive patients selected for elective aor toiliac surgery were included. Carotid duplex scanning, renal duplex s canning and/or aortorenal angiography, and recording of clinical predi ctive variables were obtained in all the patients. The statistical ana lysis included prevalence rates, multivariate analysis, and predictive values of carotid and renal duplex scanning adjusted for the observed prevalence. Greater than 50% asymptomatic stenosis in at least one of the internal carotid arteries (GAS > 50%) was detected in 47 (28%) pa tients [95% confidence interval (CI): 21.2%-34.8%]; 67 (39.9%) patient s showed greater than 60% stenosis in one or both renal arteries (RAS > 60%) (95% CI: 32.5%-47.3%). Based on current surgical indications, c arotid endarterectomy was performed in 24 (14.3%) patients and a bypas s to the renal artery in 30 (17.8%) patients. Logistic regression anal ysis accepted the following variables, in this order: carotid bruit, a ge, and ankle/brachial index for predicting carotid artery stenosis; a nd hypertension and CAS for predicting renal artery stenosis. Based on previous validation studies of duplex scanning accuracy, estimated po sitive predictive values for significant stenosis of the carotid and r enal arteries showed a range of 80.5%-89.1% and 82.3%-89.7%, respectiv ely. Routine screening of the carotid and renal arteries may be justif ied in those patients with aortoiliac aneurysmal and occlusive disease , provided there is a high prevalence of clinically significant lesion s and sufficient predictive values of duplex scanning are obtained.