Abstract 894: Stent Fracture Detected by Multislice Computed Tomography after In-Stent Restenosis Caused by “full Metal Jacket” with Drug-Eluting Stents
Background: Stented segment length and multiple stents are predictive factors for restenosis after drug-eluting stent (DES) implantation; coronary stent fracture has been noticed as a cause of in-stent restenosis (ISR). Nonetheless, clear visualization of in-vivo stent structure is not currently feasible with conventional technology. Therefore, we investigated the morphological characteristics of the stent fracture site and the correlation with ISR using multislice computed tomography (MSCT). Specifically, we looked at very long segments (ie, ≥64 mm of stented length) treated by DES, an approach colloquially referred to as a “full metal jacket.”
Methods: From January 2007 to April 2008, we performed MSCT coronary angiography in 512 consecutive patients. In these patients, a total of 38 stented lesions were treated, with at least 64 mm of overlapping DES scanned using MSCT. Stent fracture was defined as a spontaneous injury to the structure of the in vivo stent strut in the absence of any artificial process. Lesions were divided according to the presence or absence of fracture. Frequency of overlapping, vessel bending and severe calcification of the native artery were compared between the 2 groups, as well as the ISR rate.
Results: Of the entire population, lesions with “full metal jacket” had more stent fractures than those without “full metal jacket” (30% vs. 7%, P<0.0001). Of the 38 “full metal jacket” lesions, 33 lesions (87%) were available for evaluation. The average stented length in these lesions was 82.1 ± 19.6 mm, with stent fracture detected in 10 sites (30%) and observed more frequently in the right coronary artery (RCA). There were no significant differences between groups in the rate of bending of the native coronary artery or in severe calcification. The ISR rate was higher in the fracture group (30% vs. 8.6%, P=0.05).
Conclusions: Coronary stent fracture was detected in 30% of stented lesions after aggressive stenting. “Full metal jacket” was the main predictor of stent fracture, resulting in in-stent restenosis. MSCT is a feasible modality capable of providing essential information regarding stent fracture.