Prevalence of asymptomatic carotid stenosis in patients undergoing infrainguinal bypass surgery
A. T. Gentile, L. M. Taylor Jr, G. L. Moneta and J. M. Porter
Department of Surgery, Oregon Health Sciences University, Portland, USA.
BACKGROUND: The prevalence of asymptomatic carotid stenosis in patients
with lower-extremity ischemia is unknown. This report represents the
largest carotid screening program to date of patients undergoing leg
bypass. DESIGN: Patients undergoing infrainguinal bypass from 1987 through
1993 on the vascular surgery service at Oregon Health Sciences University,
Portland, underwent routine carotid duplex examinations to detect the
presence of asymptomatic carotid stenosis. PATIENTS: During the study
period, 352 patients underwent infrainguinal revascularization for
ischemia, of whom 225 (64%) had no prior carotid surgery, carotid
arteriography, or cerebrovascular symptoms. There were 117 men and 108
women, with a mean age of 67 years. The indication for surgery was limb
salvage in 67% and claudication in 33% of patients. RESULTS: Sixty-four
patients (28.4%) who required lower-extremity revascularization had
hemodynamically significant asymptomatic carotid artery stenosis or
occlusion; 12.4% had stenosis of 60% or greater, the qualifying level for
randomization in the Asymptomatic Carotid Atherosclerosis Study. Based on
these findings, eight patients with carotid stenosis of 80% or greater
underwent elective carotid endarterectomy. There were no postoperative
neurologic events in the 225 leg bypass patients. By multivariate logistic
regression analysis, the presence of carotid bruit (P < .001) and the
presence of rest pain (P = .006) were associated with carotid stenosis of
50% or greater. Limiting screening to patients with carotid bruit, limb
salvage indications for surgery, and/or advanced age excluded significant
numbers of patients with stenosis; thus, these were not effective screening
strategies. CONCLUSION: Screening carotid duplex scanning is indicated in
patients who require lower-extremity revascularization.
