Implications of the angiographic string sign in carotid atherosclerosis.
We identified 60 patients (42 men and 18 women with an average age of 62.6 years) with angiographically documented carotid stenoses of greater than or equal to 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 less than 6 or greater than 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 greater than or equal to 95% carotid stenosis and that the angiographic string sign does not affect the mode of presentation or surgical outcome of these patients.