Carotid artery stent fracture identification and clinical relevance

Abstract

This study was conducted to identify the prevalence, risk factors, and clinical relevance of carotid artery stent fracture. Commercially available carotid stents were implanted in this prospective, observational study that began in January 2004. Indications included asymptomatic patients (stenosis >80%), symptomatic patients (stenosis >60%), and ulcerated lesions (>50%). Stent integrity was assessed with plain radiography at 12 months. Data were analyzed in April 2009 on a series of 341 consecutive patients treated with carotid artery stenting with at least 12 months follow-up. Stent fracture prevalence was 3.4% at 12 months (95% confidence interval, 1.7%-6.1%). The median clinical follow-up was 30 months (range, 12-64 months) for 323 eligible patients. Treatment included 23.6% of symptomatic patients. According to univariate analysis, calcification type III increased the odds of stent fracture by more than 4.5 times (odds ratio [OR], 4.74; P = .006) and angulation >45 degrees increased the odds of stent fracture by 6.5 times (OR, 6.51; P = .008). Carotid stent cell type, stent length, and stent over-sizing were not correlated with stent fracture incidence. Stent fracture was not associated with stroke (0%), transient ischemic attack (0%), or death (0%). Restenosis was significantly associated with stent fracture (P < .001). Multivariate analysis evidenced that type III calcification (OR, 3.90; P = .029) and angulation >45 degrees (OR, 4.69; P = .026) were important risk factors for carotid stent fracture. Carotid stent fracture is a rare complication after CAS and is associated with vessel angulation, calcification, and restenosis. In this series, fracture identification was independent of stroke, transient ischemic attack, and mortality.