Stenting for carotid artery stenosis: Fractures, proposed etiology and the need for surveillance

Purpose: Carotid artery stenting is a relatively new intervention for the treatment of carotid artery stenosis, and the long-term outcomes and complications are therefore yet to be determined. In one surgeon's practice, it was found that a stent fracture was the etiological factor for recurrent stenosis. A retrospective study was therefore performed with the hypothesis that carotid stent fractures are common. The aims were to determine prevalence of fractures in this surgeon's series, risk factors, and most importantly, clinical relevance. Methods: Patients from one surgeon's private practice who had carotid stenosis deemed suitable for intervention (> 80% asymptomatic, > 70% symptomatic, 50% to 70% if an ulcerated lesion) and had suitable aortic and carotid morphology for carotid stenting between March 2004 and December 2006 were included. To enhance the quality of the measurement, two vascular surgeons and one radiologist examined the films independently to determine if there was a fracture present. Given that this was a retrospective study, there was no preconceived sample size determined. Results: Fracture prevalence was found to be 29.2% or 14 out of 48 stents. Restenosis occurred in 21% of those stents with a detected fracture, after an average follow-up of 15 months. Several anetiological factors are proposed, with a finding in this series, of a strong and significant association between the presence of calcified vessels and the presence of fractures (odds ratio 7.7; standard error 5.6; 95% confidence interval 1.9-32.0, P =.003). Conclusions: Although this is a small study, it demonstrates that carotid stent fractures do exist, and importantly, not all of them arc benign. Therefore, the authors recommend regular surveillance with plain radiography in addition to duplex ultrasonography to enable early detection of fracturing. Following detection, institution of increased surveillance frequency and/or any appropriate intervention can be implemented, to aid in the prevention of complications resulting from restenosis should it become apparent.