Duplex scanning is being used now to screen patients with suspected carotid artery disease, as the sole diagnostic test before carotid endarterectomy, and for follow-up surveillance after carotid surgery. Although the role of screening in patients with neurologic symptoms generally is accepted, noninvasive screening of asymptomatic patients remains controversial. The basic rationale for screening is to detect disease that can be treated to improve the patient's outcome. Although debate over the value of endarterectomy for asymptomatic carotid stenosis will continue, there is abundant evidence from natural history studies and clinical trials indicating that patients with asymptomatic high-grade (80% to 99% by duplex) stenoses can benefit from surgery if it can be performed with an acceptably low perioperative complication rate. Therefore, screening appears to be justified in patients with asymptomatic neck bruits and patients being evaluated for peripheral arterial or coronary artery disease. Those who are found to have moderate stenoses (50% to 79%) should be followed up at 6-month intervals to detect disease progression that may require surgery. Patients with less than 50% carotid stenoses can be followed up annually. Early restenosis is relatively common after carotid endarterectomy, occurring in about 20% of patients followed up with serial duplex scans, but it appears to have a benign natural history in the majority of patients. Reoperation is indicated only for symptomatic recurrent lesions and selected high-grade asymptomatic restenoses. An early postoperative surveillance examination is justified to provide a baseline study. The frequency of subsequent follow-up examinations will be determined by the status of the contralateral nonoperated carotid artery or the development of neurologic symptoms.
Copyright 2001 by W.B. Saunders Company