Prevalence and clinical significance of stent fracture and deformation following carotid artery stenting

Abstract

Objective: Carotid artery stenting (CAS) is a developing intervention for carotid artery stenosis, and long-term outcomes remain unclear. We examined the prevalence and clinical significance of carotid stent fractures or deformations following CAS.

Methods: Two hundred thirty-one CAS performed in 219 patients at one academic institution between August 2000 and March 2009 were reviewed. One hundred sixteen stents (57 closed cell, 59 open cell) were evaluated with multiplanar plain films of the neck to assess for stent fracture or deformation. Stent fracture was identified by wire strut disruption. Deformation was defined as an increase in stent-cell area from stent strut distortion. Study endpoints included rate of stent fracture or deformation determined using Kaplan-Meier and life table analysis. Factors associated with stent fracture or deformation were identified by Cox regression. Effect of stent fracture or deformation on recurrent carotid artery stenosis >70% requiring reintervention and postoperative stroke was studied.

Results: There were five stent fractures (4%) and 27 deformed stents (23%). Rate of stent fracture or deformation was 15% at 2 years and 50% at 4 years. Deformations were significantly more common in open cell stents than in closed cell stents (58% vs 5% at 4 years, P < .00005). Presence of calcified plaque on plain film was significantly associated with increased rate of stent fracture or deformation (P = .0006). At median follow-up of 25 months, restenosis requiring treatment occurred in four (5%) and late stroke in one (1%). Neither stent fracture nor deformation was associated with late stroke or reintervention.

Conclusions: Stent fracture and deformation is not uncommon following CAS and is associated with the presence of heavy calcification. Whether a carotid stent fractures or deforms correlates with stent design. Larger studies are necessary to determine the possible clinical significance of carotid stent fracture and deformation.