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We identified 60 patients(42 men and 18 women with an average age of 62.6 years)with angiographically documented carotid stenosis of>/=95%;a string sign was demonstrated in 28.Twenty of the 60 patients(33%)were asymptomatic on presentation,26(43%)had hemispheric transient ischemic attacks,21(35%)had amaurosis fugax,and nine(15%)had previous ipsilateral infarctions.Demographics,mode of presentation,and prevalence of atherosclerotic risk factors were not significantly different between patients with and without a string sign.Doppler frequencies recorded in patients with a string sign were<6 or>16 KHz.Real-time ultrasonography imaged a patent lumen in all but three cases with a string sign.Surgery was performed in 26 patients with a string sign and in 21 patients without a string sign.The rate of major perioperative complications was not influenced by the presence of a string sign,contralateral extracranial stenosis,or ipsilateral siphon stenosis.Average lumen size of the endarterectomy specimens was 0.94 mm in those with and 1.7 mm in those without a string sign.We conclude that combined noninvasive testing has a sensitivity of 83%for demonstrating a residual lumen in patients with>/= 95%carotid stenosis and that the angiographic string sign does not affect the mode of presentation or surgical outcome of these patients. |
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