The presence of long and heavily calcified lesions predisposes for fracture in patients undergoing stenting of the first part of the subclavian artery.
OBJECTIVE
To determine the prevalence and risk factors of subclavian artery stent fractures and to investigate their impact on in-stent restenosis development.


METHODS
One hundred eight patients (65 females; median age, 58.3 years [interquartile range, 53.4-65.5 years]) with steno-occlusive disease of the first part of the subclavian artery who underwent stenting (N = 108 stents; balloon-expandable, 83.3%; self-expandable, 16.7%) between 2005 and 2015 and returned for a fluoroscopic examination of the implanted stents in 2017 were included in our study. Fractures were type I (single strut fracture), type II (multiple strut fractures without deformation), type III (multiple strut fractures with deformation), type IV (multiple strut fractures with acquired transection but without gap), or type V (multiple strut fractures with acquired transection with gap in the stent body). Stent patency was monitored by duplex ultrasound imaging. The Mann-Whitney U and Fisher's exact tests; Kaplan-Meier, receiver operating characteristic, and logistic regression analyses; as well as a log-rank test were used as statistical methods.


RESULTS
The median follow-up was 73.8 months (interquartile range, 35.6-104.2 months). Thirty-eight fractures (35.2%) were detected; fractures were type I in 13, type II in 12, type III in 6, type IV in 4, and type V in 3 cases. Multivariable logistic regression analysis revealed the presence of long (≥20 mm) lesions (odds ratio, 3.3; 95% confidence interval, 1.3-8.4; P = .012) and heavy calcification (odds ratio, 4.7; 95% confidence interval, 1.7-12.7; P = .002) to be significant independent predictors of stent fracture. The primary patency rates were significantly worse (P = .035) in patients with stent fracture compared with those without stent fracture.


CONCLUSIONS
Stent fractures frequently occur. Patients with long and/or heavily calcified lesions require closer follow-up.