title: Long-term changes in neointimal hyperplasia following implantation of bare metal stents assessed by integrated backscatter intravascular ultrasound.
abstract: In-stent restenosis (ISR) is a common phenomenon with bare metal stents (BMSs) in the early stage after implantation. However, ISR occurs at a lower rate with long time after BMS implantation. We assessed changes over time in neointimal hyperplasia following BMS implantation using integrated backscatter intravascular ultrasound (IB-IUVS). Thirty-six patients who received target lesion revascularization (TLR) to treat ISR were classified according to the duration of the interval between stent implantation and TLR: the early group (within first year n = 25) and the VL group (very late ISR ≥5 years, n = 11). IB-IUVS was used to evaluate within-stent sites from the proximal to the distal edge of the stent. IB-IVUS color maps were then constructed by tracing the stent struts and vessel lumen. Neointimal tissue was classified as high-IB (IB <-29 dB; a representative cord of calcification), middle-IB (-49 dB ≤ IB < -29 dB; fibrosis), or low-IB (-49 dB ≤ IB; lipid pool). We compared percent (%) volume, average %area of cross-sectional area (CSA), and %area of minimum CSA of each component between the groups. There were no significant differences in %volume, average %area of CSA, or %area of minimum CSA for the high-IB component between groups. The %low-IB components were 20.0 ± 8.8 % for volume, 20.1 ± 8.9 % for mean CSA, and 17.6 ± 8.5 % for minimum CSA in the early group. On the other hand, in the VL group, the %low-IB components were significantly increased to 31.8 ± 7.9 % for volume (p < 0.01 vs. the early group), 31.2 ± 7.6 % for mean CSA (p < 0.01 vs. the early group), and 33.1 ± 12.3 % for minimum CSA (p < 0.01 vs. the early group). By contrast, the %middle-IB component showed a reduction in extended time, with %volume of the middle-IB decreasing from 78.3 ± 8.1 to 66.4 ± 7.1 %, average mean %area of CSA from 78.2 ± 8.2 to 66.9 ± 6.9 %, and % area of minimum CSA from 80.7 ± 7.9 to 65.5 ± 11.4 % (p < 0.01;. the early vs. the VL group). Our results suggest that in-stent neointimal tissues developing over time consist of an increased low-IB component and a decreased middle-IB component and may contribute an increased of lipidemic component and a decreased of fibrotic component.
authors: Department of Cardiology, Gifu Prefectural General Medical Center, 4-6-1 Noisshiki, Gifu, 500- 8717, Japan. shin19711015@yahoo.co.jp
authors: Shinichiro
authors: S
authors: Tanaka
authors: Toshiyuki
authors: T
authors: Noda
authors: Makoto
authors: M
authors: Iwama
authors: Shintaro
authors: S
authors: Tanihata
authors: Masanori
authors: M
authors: Kawasaki
authors: Kazuhiko
authors: K
authors: Nishigaki
authors: Taro
authors: T
authors: Minagawa
authors: Sachiro
authors: S
authors: Watanabe
authors: Shinya
authors: S
authors: Minatoguchi
mesh_terms: D000368:Aged; D016009:Chi-Square Distribution; D017023:Coronary Angiography; D023903:Coronary Restenosis / Q000000981:diagnostic imaging* / Q000209:etiology / Q000628:therapy; D003331:Coronary Vessels / Q000000981:diagnostic imaging*; D005260:Female; D005355:Fibrosis; D006801:Humans; D006965:Hyperplasia; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D008670:Metals; D008875:Middle Aged; D058426:Neointima; D062645:Percutaneous Coronary Intervention / Q000009:adverse effects / Q000295:instrumentation*; D011237:Predictive Value of Tests; D011474:Prosthesis Design; D012189:Retrospective Studies; D015607:Stents; D013997:Time Factors; D018084:Ultrasonography, Interventional
chemical_list: D008670:Metals