Stent Coning Induces Distal Stent Edge Stenosis

Abstract

Purpose: Stent coning is conular morphological changes at the distal end of wire-braided closed-cell stents. We discuss its incidence, predictors, and outcomes. Materials and Methods: We reviewed data on 178 carotid arteries (172 patients) that were treated by carotid artery stenting (CAS) with wire-braided stents. All patients were followed-up by carotid duplex ultrasound (DUS) studies to detect in-stent restenosis (ISR) and stent-edge stenosis. In patients manifesting stent coning, we also obtained neck radiographs. Results: Stent coning was detected in 11 arteries (6.2%). Internal carotid artery/common carotid artery ratio and use of a post dilation balloon were associated with coning (p<0.05). On radiographs obtained at 3-months follow-up, all instances of coning had disappeared spontaneously. Follow-up DUS detected 5 instance of stent-edge stenosis at 3- or 6 months. Stent-edge stenosis occurred only in arteries with coning. At 6 months post-CAS, Kaplan-Meier analysis revealed a cumulative freedom from stent-edge stenosis of 54.5% in vessels with coning; stent-edge stenosis was not observed in arteries without coning (p<0.05). At DUS follow-up performed a mean of 32.8 months post-CAS, 2 arteries without coning manifested ISR >50% (p=0.72). At clinical follow-up carried out a mean of 38.4 months after the procedure, none of our patients had developed new neurologic ischemic symptoms. Conclusions: While stent coning is self-curing, it may be associated with the late development of stent-edge stenosis.