Objectives Little is known about causes of stent fracture (SF) after sirolimus-eluting stent (SES) implantation. The present study investigated differences of the IVUS findings between segments with and without stent fracture in patients treated with SES. Method Since January 2004, SF (25 fractures in 24 patients) after SES implantation were discovered and underwent intravascular ultrasound (IVUS) examination. Measurements were performed at 7 cross sections in the same stent: center of SF site, proximal and distal edges of fractured stent and 4 remote sites 2.5 amd 5.0mm proximal and distal to SF site. Result IVUS parameters at the center of stent fracture were not different from the other sites (EEM area[mm2]; 16.44±3.50, 15.73±3.12, 15.97±3.64, 15.94±3.76, 15.72±3.64, 15.64±3.95, 15.60±4.18, p=ns/ Stent area[mm2]; 8.46±2.28, 7.88±2.17, 7.79±2.26, 7.75±2.08, 7.75±2.09, 7.82±1.87, p=ns) except Lumen area(mm2) (8.15±2.31[p<0.001], 7.45±2.14[p=0.008], 8.14±8.90[p=ns], 6.48±2.26, 6.54±2.28[p=ns], 6.99±2.18[p=ns], 7.50±2.00[p=0.007]). Stent under/over expansion, regional vessel remodeling, or excessive P&M (possible NIH) accumulation were not observed (P&M; 7.98±2.22 vs. 7.85±2.15 vs. 8.18±2.75 vs. 7.83±8.74 vs. 7.98±2.33 vs. 7.89±2.60 vs. 7.78±2.77/ NIH; 0.32±0.87 vs. 0.43±0.42 vs. -0.35±8.73 vs. 1.20±1.33 vs. 0.76±0.88 vs. 0.18±0.35). Incomplete stent appositions were more frequently found at the fractured stent edges compared with other sites (Table). Calcium profiles were not different between sites. Conclusion Incomplete stent apposition is more frequently found at the fractured stent edges after SES implantation, suggesting a role in the pathogenesis of this adverse event.
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