Incidence and Clinical Outcomes of Stent Fractures
What is the incidence of stent fracture (SF) and its correlation with clinical events after drug-eluting stent (DES) implantation, and the outcome of re-intervention for symptomatic in-stent restenosis (ISR) induced by SF?
A total of 6,555 patients with 16,482 DES in 10,751 diseased vessels and surveillance angiography between November 2003 and January 2014 were prospectively studied. The primary endpoints included the incidence of SF, ISR, target lesion revascularization (TLR), and definite stent thrombosis (ST) at the end of follow-up before and after propensity-score matching. Clinical outcomes after TLR were also followed up. The survival curve at the patient level was estimated using the Kaplan–Meier method and was compared using log-rank analysis.
The SF rate was detected in 803 (12.3%) patients, 3,630 (22.0%) stents, and 1,852 (17.2%) diseased vessels. SF increased over time. SF was associated with higher unadjusted rates of ISR (42.1%), TLR (24.8%, n = 379), and definite ST (4.6%) compared with stents without fracture (10.7%, 6.6%, and 1.03%, all p < 0.001), and the differences remained significant after propensity-score matching (all p < 0.05). There was no significant difference in any-cause or cardiac mortality between patients with and without SF. After 1,523 days of follow-up since the first surveillance angiography, repeat ISR was detected in 90 of 379 (23.8%) stents after re-intervention, and six (7.5%) stents required repeat TLR.
The authors concluded that SF is more frequently observed after DES implantation.
The major findings of the present study are that the prevalence of SF at the stent level was quite high at 22.0%, and the prevalence increased over the 2-year follow-up. Furthermore, SF was associated with significantly increased angiographic and clinical events after propensity-score matching, which did not translate into significant differences in mortality among the two groups. Additional studies on mechanical movement of heart and vascular dynamic stress are indicated to better understand the mechanisms of SF so that stents with less likelihood of fracture can be developed.
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