Ability of the carotid duplex scan to predict stenosis, symptoms, and plaque structure

The duplex scan with its improved technology has allowed clinicians to visualize noninvasively the carotid bifurcation. We investigated whether the duplex scan, with its ability to visualize plaque structure, can reliably predict the major components of different plaques seen in pathologic studies. Furthermore, we studied whether it could correlate these findings with the presenting symptoms of patients and predict which patients would benefit from early endarterectomy.

We performed a retrospective study of 84 patients during a 43-month period. The arteriogram, duplex scans, symptoms, and pathologic examination of the carotid atheroma in each patient were reviewed. The specimens were divided into three categories depending on the major component found in pathologic studies. One group consisted of calcific plaques, another was predominantly fibrosis and cholesterol, and the third was plaques with intramural hemorrhage. The angiograms and duplex scans were separately interpreted. Patients with symptoms (81%) were divided into those with amaurosis fugax (19%), transient ischemic attacks (58%), and cerebral vascular accidents (3%).

The agreement between duplex scan findings and arteriograms concerning the percent stenosis was 95%. There was no correlation, however, between the presence or type of symptoms and the plaque structure as seen in pathologic studies or on the duplex scan.

At this stage of technology the duplex scan is most reliable in detecting hemodynamically significant lesions. Its ability to predict symptoms or findings at surgery and possibly to alter treatment is at best limited.