Evaluation of in-stent neointimal tissue components using integrated backscatter intravascular ultrasound: comparison of drug-eluting stents and bare-metal stents

Abstract

Although in-stent restenosis (ISR) occurs after drug-eluting stents (DES) implantation, neointimal tissue characteristics have not been fully investigated. We assessed neointimal tissue components using integrated backscatter intravascular ultrasound (IB-IVUS) after DES and bare-metal stents (BMS) implantation. Fifty-seven consecutive patients with 61 lesions underwent repeated percutaneous coronary intervention (PCI) for the treatment of ISR (DES: 24 lesions, BMS: 37 lesions). PCI was performed using plain old balloon angioplasty (POBA). Before PCI, we assessed neointimal tissue characteristics using IB-IVUS. Neointima was divided into four categories: category 1 (-11 to -29 dB), category 2 (-29 to -35 dB), category 3 (-35 to -49 dB), and category 4 (-49 to -130 dB) according to IB values. We compared neointimal tissue components between DES and BMS. Thirty-three patients with 33 lesions (DES: 17, BMS: 16) were finally included. Neointima was predominantly composed of category 3 tissue in both groups (DES: 68 ± 8%, BMS: 73 ± 5%, P = 0.053). DES had a broader distribution of category 4 tissue component than BMS. After POBA, distal slow flow phenomenon occurred in 5 of DES (29%), whereas none of BMS. In DES, the optimal threshold of category 4 tissue to predict distal slow flow phenomenon after POBA was 30% (sensitivity: 100%, specificity: 92%). Neointima was mainly composed of category 3 tissue at ISR site, irrespective of DES or BMS. In DES, there was a subgroup with category 4 rich tissue, which caused distal slow flow phenomenon after POBA. IB-IVUS might be useful to identify vulnerable neointima in DES restenosis.

Neointimal tissue component assessed by tissue characterization with 40 MHz intravascular ultrasound imaging: Comparison of drug‐eluting stents and bare‐metal stents

“…Muraoka et al demonstrated by integrated backscatter‐IVUS that intra‐DES neointima was associated with low integrated backscatter value (allegedly‐corresponding to lipid), which caused distal slow flow phenomenon after balloon angioplasty . Although absence of definition of necrotic tissue in integrated backscatter‐IVUS make it impossible to compare our observation with their results, our iMap and their integrated backscatter‐IVUS results are in agreement with that intra‐DES neointima was composed of less‐fibrotic and less‐stabilized tissue with a broader distribution of various tissue components as compared with intra‐BMS neointima.…”

“…Taken together, in‐stent restenotic lesions may not be as stable as previously thought; and in vivo assessment of neointimal tissue component becomes more important than before because it was not clear why some in‐stent neoatherosclerosis culminated in acute coronary syndrome and some did not. Although IVUS and optical coherence tomography are potential modalities to assess the neointimal tissue in this moment , IVUS‐based tissue characterization modalities have more quantitative parameters as compared with qualitative neointimal assessment by optical coherence tomography.…”

The role of integrated backscatter intravascular ultrasound in characterizing bare metal and drug-eluting stent restenotic neointima as compared to optical coherence tomography

“…In our study, however, there was no significant difference between percentage lipid and fibrous neointima in DES restenosis as compared to BMS restenosis. These findings are consistent with the results of IB-IVUS analysis by Muraoka et al [22]. The discrepancy between the two modalities could be related to differences in definitions for tissue characterization.…”

“…Muraoka et al [22] have reported a subgroup of DES restenosis with low backscatter value (allegedly-corresponding to lipid) in which distal SF was observed after balloon angioplasty (POBA). In our study, SF occurred more frequently at MSA sites with a nonhomogeneous pattern where the percentage lipid neointima was found to be greater as compared to sites with a homogeneous pattern.…”

Renal Dysfunction and Atherosclerosis of the Neointima following Bare Metal Stent Implantation

“…An IB-IVUS study has also found neointima within BMS-associated lesions to contain mainly middle-IB tissue, suggesting fibrous tissue [20,21]. Luminal renarrowing of the stented segment has been reported to be a progressive process [22], and histopathological and imaging studies, such as virtual histology IVUS and optical coherence tomography, have demonstrated changes in neointimal tissue characteristics in the late phase after BMS implantation.…”