Appropriate frequency of carotid duplex testing following carotid endarterectomy

: The value of carotid duplex analysis is well proven for the diagnosis of carotid bifurcation occlusive disease, but its use in the postoperative setting is less well defined. : A series of 281 carotid endarterectomies were performed in 222 patients. A protocol of serial duplex examinations was established, with tests performed at the time of the first postoperative clinic visit and every 6 months thereafter. The goal of postoperative surveillance was to identify critical restenotic carotid lesions of greater than 80% diameter reduction and determine the incidence of subsequent carotid occlusion and neurologic events. : Critical restenoses developed in 25 (8.9%) of the arteries and occlusions occurred in 12 (4%). Restenosis occurred with greatest frequency during the first year after operation (5%), but continued to develop with a frequency of approximately 2% per year thereafter. Postoperative carotid occlusions occurred at a rate of approximately 1% per year. Known restenotic lesions progressed to occlusion over a mean duration of 11 months. Stroke was infrequent in patients with critical restenoses (4%) until the lesions progressed to occlusion (33%). : These observations suggest that a protocol of semiannual duplex testing into the late postoperative period may identify critical carotid restenotic lesions prior to the development of carotid occlusion and stroke.