Noninvasive evaluation and management of the "asymptomatic" carotid bruit

Cervical bruits in patients who are asymptomatic or who have nonhemispheric neurological symptoms present a universal challenge. Of 4,000 patients evaluated noninvasively for carotid occlusive disease, 1,287 presented with "asymptomatic" bruits (697 had nonhemispheric neurological symptoms and 590 were clinically asymptomatic). Carotid phonoangiography (CPA), the visual analysis of carotid bruits, identifies bruits indicative of significant stenosis, documents progression, and differentiates bruits of carotid bifurcation and sub-bifurcation origin. Sub-bifurication bruits were diagnosed in 619, insignificant bifurcation bruits in 426, and significant carotid bruits in 242 patients by CPA. Oculoplethysmography (OPG) evaluates the hemodynamic significance of carotid bruits by comparative timing of simultaneously recorded ocular and ear lobe pulses. OPG detected 273 asymptomatic bruit patients with significant internal carotid flow reduction and indicated 5% of the bifurcation bruits were of external carotid origin. An accuracy of 89% in determining greater than 40% stenosis by OPG/CPA in 295 patients having arteriography increases to 97% when both OPG and CPA are positive. Six-month to 70-month clinical follow-up of the 1,287 patients documented 154 carotid endarterectomies and 38 strokes. Analysis of the strokes favors arteriography and operation only for those patients with appropriately positive or progressive OPG/CPA or with focal transient ischemic attacks (TIAs).