Stent fracture, an incidental finding or a significant marker of clinical in-stent restenosis?

BACKGROUND: The predictors and clinical significance for stent fracture (SF) in drug-eluting stents (DES) remain unknown. We identified procedural factors leading to SF and its clinical consequences in DES. METHODS: Percutaneous coronary interventions were performed on 3,920 patients with DES over 12 months. In-stent restenosis (ISR) of DES was observed in 188 cases with 121 cases (64.4%) receiving a sirolimus-eluting stent (SES) and 67 (35.6%) a paclitaxol-eluting stent (PES). RESULTS: SF was identified in 35 (18.6%) of the 188 cases. The 35 cases were then compared with 153 cases of ISR without angiographic evidence of SF. SF was identified in 29 (23.9%) SES compared with 6 (9.0%) in PES (P < 0.05). With univariate analysis, additional factors associated with SF included longer mean stented segment length, male gender, overlapping stents, vessel segment angulation >75 degrees , and more stents (all P < 0.05). With multivariate adjustment, three factors, i.e., stenting on a bend >75 degrees (OR = 13.8, 95%CI 3.7 to 51; P < 0.001), SES (OR = 4.1, 95%CI 1.3 to 13.4; P < 0.018) and overlapping stented segments (OR = 3.9, 95%CI 1.1 to 14.1; P < 0.041) were statistically significant independent predictors of SF while larger stent diameter was protective (OR = 0.14, 95%CI 0.04 to 0.70; P < 0.017). CONCLUSION: SF proved to be associated with angiographically-documented clinical ISR. Although the exact mechanism is unknown, factors that appear to play a negative role in SF include vessel tortuosity, use of SES and overlapping stents. Larger stent diameter was protective. Further studies are needed to better define the factors important in the mechanism of SF.