Duplex morphologic features of the reconstructed carotid artery: Changes occurring more than five years after endarterectomy

Purpose: To determine the late morphologic appearance of the carotid artery after endarterectomy and to relate the morphologic characteristics to the development of recurrent carotid stenosis and subsequent neurologic symptoms. Methods: Eighty-eight carotid reconstructions (51% included patch angioplasty) in 82 patients were studied 5 or more years after carotid endarterectomy. Duplex color flow imaging was used to determine morphologic characteristics of the carotid endarterectomy site and to document the occurrence, time interval, and progression of recurrent internal carotid artery stenosis. The spatial orientation of recurrent wall thickening, presence of calcium, arterial wall texture, and presence of laminar flow were evaluated. Recurrent stenoses were categorized using standard duplex criteria. Results: The mean duration of follow up was 99 months (range, 60 to 138 months). Arterial wall calcium was identified in 23% (n = 18), a smooth luminal surface in 57% (n = 46), and laminar flow in 52% (n = 42). Recurrent wall thickening developed in 58 vessels (66%), involving the posterior segment of the vessel in 95%, and anterior, lateral, or medial aspects in 24% (n = 14). Restenosis > 50% diameter reduction occurred in 4% of common carotid arteries (n = 3) and in 15% of internal carotid arteries (n = 13). Ten of the internal carotid artery restenoses occurred after a mean of 76 months (range, 13 to 132 months), and the three remaining patients had asymptomatic occlusions after a mean of 61 months (range, 1 to 96 months). Neurologic events referable to the reconstructed carotid artery occurred in three patients at a mean of 77 months; two were a result of recurrent carotid disease. One symptomatic patient and two asymptomatic patients (3.7%) underwent a second ipsilateral reconstruction for recurrent high-grade stenosis. Conclusions: The carotid artery remains smooth, with laminar flow and without calcification, in the majority of reconstructions that were observed over a long term. There is a low incidence of subsequent ipsilateral neurologic events or significant recurrent stenosis, both of which usually occur late in the postoperative period. This study documents the long-term durability of carotid endarterectomy in providing risk reduction for stroke.