Carotid Stent Fractures Are Not Associated With Adverse Events: Results From the ACT-1 Multicenter Randomized Trial (Carotid Angioplasty and Stenting Versus Endarterectomy in Asymptomatic Subjects Who Are at Standard Risk for Carotid Endarterectomy With Significant Extracranial Carotid Stenotic Disease).

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 ACT-1 trial (Carotid Angioplasty and Stenting Versus Endarterectomy in Asymptomatic Subjects Who Are at Standard Risk for Carotid Endarterectomy With Significant Extracranial Carotid Stenotic Disease). METHODS: ACT-1 is a prospective multicenter trial of patients who have standard surgical risk with severe asymptomatic carotid artery stenosis randomly assigned to carotid artery stenting or carotid endarterectomy (Abbott Vascular). The primary end point 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 randomly assigned 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 carotid artery stenting during a mean follow-up of 3.1±1.6 years, 939 had at least 1 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 1 x-ray during the follow-up. Of 826 (80.9%) subjects who underwent both duplex ultrasound and x-ray, 822 (99.5%) were interpretable. There was no association between stent fracture and the primary end point (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://www.clinicaltrials.gov. Unique identifier: NCT00106938.

Randomized Trial of Stent versus Surgery for Asymptomatic Carotid Stenosis.

BACKGROUND: Previous clinical trials have suggested that carotid-artery stenting with a device to capture and remove emboli ("embolic protection") is an effective alternative to carotid endarterectomy in patients at average or high risk for surgical complications. METHODS: In this trial, we compared carotid-artery stenting with embolic protection and carotid endarterectomy in patients 79 years of age or younger who had severe carotid stenosis and were asymptomatic (i.e., had not had a stroke, transient ischemic attack, or amaurosis fugax in the 180 days before enrollment) and were not considered to be at high risk for surgical complications. The trial was designed to enroll 1658 patients but was halted early, after 1453 patients underwent randomization, because of slow enrollment. Patients were followed for up to 5 years. The primary composite end point of death, stroke, or myocardial infarction within 30 days after the procedure or ipsilateral stroke within 1 year was tested at a noninferiority margin of 3 percentage points. RESULTS: Stenting was noninferior to endarterectomy with regard to the primary composite end point (event rate, 3.8% and 3.4%, respectively; P=0.01 for noninferiority). The rate of stroke or death within 30 days was 2.9% in the stenting group and 1.7% in the endarterectomy group (P=0.33). From 30 days to 5 years after the procedure, the rate of freedom from ipsilateral stroke was 97.8% in the stenting group and 97.3% in the endarterectomy group (P=0.51), and the overall survival rates were 87.1% and 89.4%, respectively (P=0.21). The cumulative 5-year rate of stroke-free survival was 93.1% in the stenting group and 94.7% in the endarterectomy group (P=0.44). CONCLUSIONS: In this trial involving asymptomatic patients with severe carotid stenosis who were not at high risk for surgical complications, stenting was noninferior to endarterectomy with regard to the rate of the primary composite end point at 1 year. In analyses that included up to 5 years of follow-up, there were no significant differences between the study groups in the rates of non-procedure-related stroke, all stroke, and survival. (Funded by Abbott Vascular; ACT I ClinicalTrials.gov number, NCT00106938.).

Carotid artery stent implantation: evaluation with multi-detector row CT angiography and virtual angioscopy--initial experience.

Approval for this HIPAA-compliant study was obtained from the institutional review board; informed consent was not required for retrospective review of patient studies that had been performed for clinical evaluation. The purpose of this study was to retrospectively compare the accuracy of intrastent luminal diameter, as measured on transverse computed tomographic (CT) angiograms and virtual angioscopic views, with the manufacturer's specifications for phantom diameter and with digital subtraction angiographic (DSA) measurements of stent diameter obtained in patients. Intrastent diameter was measured by using standard and stent-optimized reconstruction kernels with three window settings. Endoluminal virtual angioscopic views of the stent-containing vessels were also generated. Measurements at CT angiography were compared with known specifications for the phantom and with DSA measurements in patients. Erroneous measurements of intrastent diameter occurred when a standard kernel and nonoptimized window settings were used. A set of parameters that minimized error relative to measurements obtained at DSA was also identified. Virtual angioscopy helped demonstrate morphologic aspects of stenosis that were otherwise difficult to appreciate.