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 stentfracture.Methods: Commercially available carotid stents were implanted in this prospective, observational study that began inJanuary 2004. Indications included asymptomatic patients (stenosis >80%), symptomatic patients (stenosis >60%), andulcerated lesions (>50%). Stent integrity was assessed with plain radiography at 12 months. Data were analyzed in April2009 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 clinicalfollow-up was 30 months (range, 12-64 months) for 323 eligible patients. Treatment included 23.6% of symptomaticpatients. 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° 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. Stentfracture was not associated with stroke (0%), transient ischemic attack (0%), or death (0%). Restenosis was significantlyassociated with stent fracture (P < .001). Multivariate analysis evidenced that type III calcification (OR, 3.90; P .029)and angulation >45° (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.