Carotid Stent Fractures are not Associated with Adverse Events: Results from the ACT 1 Multicenter Randomized Trial

Background —The impact of carotid artery stent fractures on the incidence of adverse clinical events remains unclear. The objective of this study is to report the stent fracture rate and its association with in-stent restenosis and adverse outcomes in the Asymptomatic Carotid Trial (ACT)-1. Methods —ACT-1 is a prospective multicenter trial of standard surgical risk patients with severe asymptomatic carotid artery stenosis randomized to carotid artery stenting (CAS) or carotid endarterectomy (CEA) (Abbott Vascular, Santa Clara, California, USA). The primary endpoint was a composite of death, stroke or myocardial infarction during the 30 days after the procedure or ipsilateral stroke during the 365 days after the procedure. After 771 patients were enrolled, successively randomized patients were required to undergo annual radiographic (X-ray) analysis for stent fracture. Images were independently adjudicated by a core laboratory. Results —Of 1021 patients treated with CAS during a mean follow-up of 3.1 ± 1.6 years, 939 had at least one X-ray during the follow-up period. Stent fracture was reported in 51 (5.4%) patients. With a maximum follow up period of 5 years, adverse clinical outcomes occurred in 39 patients with at least one X-ray during the follow-up. Of 826 (80.9%) subjects who underwent both DUS and X-ray, 822 (99.5%) were interpretable. There was no association between stent fracture and the primary endpoint (P=0.86) or with restenosis (P=0.53). Conclusions —In this large, independently-adjudicated, multicenter study, the stent fracture rate was low and not associated with major adverse clinical events or in-stent restenosis. Clinical Trial Registration —URL: https://clinicaltrials.gov Unique Identifier: NCT00106938