ACCURACY CF DUPLEX VERSUS ANGIOGRAPHY IN PATIENTS UNDERGOING CAROTID SURGERY

The operative findings of 23 carotid arteries were compared with pre-o perative duplex scans and angiography. Both duplex and angiography had a high degree of accuracy in detecting haemodynamically significant l esions of 50-99% (88 and 92%, respectively). Their accuracy, however, in correctly predicting the grade of stenosis was significantly lower; 30 and 48%, respectively (P<0.001). They each exhibited an accuracy o f 70% and 78%, respectively, in the detection of ulceration. Overall, both duplex and angiography displayed an accuracy of 87% in indicating the proper management course. The combination of bath investigations increased this accuracy to 94.6%. In severely stenotic lesions, duplex to rule out occlusion was not reliable. On statistical analysis, ther e was no difference between duplex and angiography in predicting haemo dynamically significant lesions of 50-99%, estimating the grade of ste nosis, the detection of ulceration, or indicating the proper managemen t course. In most situations, duplex alone equalled the accuracy of an giography in the pre-operative assessment of patients for carotid surg ery. For stenotic lesions of >90%, however, we recommend supplemental angiography to rule out occlusion.