Current Concepts of Cerebrovascular Disease — Stroke The Asymptomatic Carotid Bruit — Operate or Not?

THE QUESTION of how to manage the patient with an asymptomatic bruit is one which is still unsolved and the subject of considerable controversy. By definition a cervical carotid bruit is one well localized to the midcervical region just behind and below the angle of the mandible. The differential diagnosis of cervical bruit includes physiological murmurs of no significance; venous hum; arteriovenous fistula; angiomatous malformations; atherosclerosis of the brachiocephalic, subclavian, vertebral, or carotid arteries; loops, kinks, and fibromuscular dysplasia of the carotid artery; and murmurs transmitted from the upper mediastinum. The midcarotid bruit is usually localized and either disappears or diminishes in intensity as one moves the stethoscope down the neck. The bruit tends to become more apparent when stenosis is 50% or greater but may actually disappear when stenosis reaches 85% to 90%. The degree of correlation of internal carotid artery stenosis with an audible bruit is somewhere between 75% and 85%, according to Thompson. On the other hand, over-all correlation between demonstrable carotid disease and bruits is about 60% since stenotic lesions may be demonstrated on the arteriogram when an audible bruit is not present. There is no doubt that when present in a patient with symptoms related to the ipsilateral eye or cerebral hemisphere, carotid bruit is a significant clinical finding. The controversy arises with respect to the significance of the bruit in the absence of any such symptoms.