Carotid artery stent fracture identification and clinical relevance.

BACKGROUND: This study was conducted to identify the prevalence, risk factors, and clinical relevance of carotid artery stent fracture.

METHODS: 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.

RESULTS: 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.

CONCLUSIONS: 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.