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Background: In-stent restenosis (ISR) remains a clinical challenge in the drug-eluting stent (DES) era. Neoatherosclerosis is a recognized mechanism, but tissue responses after drug-coated balloon (DCB) therapy may present with atypical morphologies.Case presentation: We report a 55-year-old man with recurrent angina and ISR nine years after DES implantation and one year after DCB angioplasty. Optical coherence tomography (OCT) revealed a rare striped, low-attenuation plaque protruding into the lumen from outside the stent struts. This lesion lacked lipid, calcification, or macrophages, making it difficult to classify as typical neoatherosclerosis. The morphology suggested layered neointimal remodeling with possible thrombus organization after DCB treatment. The lesion was successfully treated with excimer laser coronary angioplasty, scoring balloon dilatation, and DCB angioplasty.
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Conclusion: This is, to our knowledge, the first report of a striped, low-attenuation plaque protruding into the stent lumen. Recognition of such atypical ISR morphologies may enhance understanding of neointimal healing after DCB treatment and guide interventional strategies.Keywords
In-stent restenosis
Optical coherence tomography
Drug-coated balloon
Neoatherosclerosis
Thrombus organization
Case report
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Introduction
In-stent restenosis (ISR) after drug-eluting stent (DES) implantation remains a therapeutic challenge. Neoatherosclerosis, defined as the development of atherosclerotic changes within the neointima of DES, is recognized as one of the major mechanisms of late stent failure [1]. Optical coherence tomography (OCT) allows detailed tissue characterization and has revealed diverse ISR morphologies. Here, we describe a rare OCT finding of a striped, low-attenuation plaque protruding into the lumen from outside the stent struts in a patient with recurrent ISR one year after drug-coated balloon (DCB) therapy.
Case presentation
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A 55-year-old man with multiple cardiovascular risk factors presented with recurrent angina. Nine years earlier, XIENCE Alpine stents (Abbott Vascular, USA) had been implanted in the proximal to mid-left anterior descending artery (LAD). One year before the current admission, a DES was implanted in the right coronary artery, and DCB angioplasty was performed for LAD ISR.Follow-up angiography revealed a hazy lesion in the mid-LAD, with a fractional flow reserve of 0.72, confirming significant ischemia (Fig. 1A). PCI was therefore scheduled.
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OCT (Dragonfly Opstar; Abbott Vascular) demonstrated a striped, low-attenuation plaque protruding into the lumen from outside the stent struts (Fig. 1A1–3). This unique morphology suggested a layered neointimal change following prior DCB therapy, including possible thrombus organization and healing processes, rather than classical neoatherosclerosis.The lesion was treated with excimer laser coronary angioplasty (ELCA; Philips, USA; 1.4 mm C-type catheter, 60 mJ/mm², 40 Hz), followed by lesion preparation using a 3.5×13 mm scoring balloon (Aperta NSE, Nipro, Japan). Post-ablation OCT showed partial reduction of the protruding tissue (Fig. 1B). Flow compromise occurred in the diagonal branch, which was managed with balloon dilatation using a Ryurei 1.5×10 mm semi-compliant balloon (Terumo, Japan).
Finally, a SeQuent Please Neo 3.5×30 mm paclitaxel-coated balloon (Nipro) was applied to the LAD, followed by snuggled kissing balloon inflation involving the diagonal branch (Fig. 1C). Final OCT demonstrated adequate lesion expansion and compression of the protruding tissue (Fig. 1D, D1–3).
Discussion
This case highlights an unusual OCT morphology of a striped, low-attenuation plaque protruding into the stent lumen. Unlike typical neoatherosclerosis, which is characterized by lipid deposition, calcification, or macrophage accumulation, this lesion lacked such features. Instead, its layered appearance suggested neointimal remodeling after prior DCB angioplasty, possibly reflecting thrombus healing or dissection repair.
Neointimal remodeling after DCB therapy has been increasingly recognized. A recent study reported layered tissue patterns on OCT after DCB treatment, likely representing complex healing processes [2]. Moreover, previous OCT investigations have demonstrated a variety of neointimal changes following DCB therapy, such as progression or regression of neoatherosclerosis, calcifications, uncovered struts, evaginations, and even mushroom-like protrusions [3]. These findings underscore the spectrum of ISR morphologies after DCB treatment.
This case illustrates the diverse morphological patterns of ISR and emphasizes the diagnostic value of OCT. Recognition of such atypical features may refine our understanding of vascular healing after DCB therapy and guide individualized interventional strategies.
Limitations
This report is limited by the absence of OCT or angiographic images from the prior DCB procedure, which would have provided additional insights into lesion evolution. Furthermore, the image quality in Fig. 1D was suboptimal, although interpretation remained feasible.
Conclusion
We report a rare OCT finding of a striped, low-attenuation plaque protruding into the stent lumen during recurrent ISR after DCB angioplasty. This morphology likely represents layered neointimal remodeling with thrombus healing, rather than typical neoatherosclerosis. Further case accumulation is warranted to clarify its clinical significance.
List of Abbreviations
DCB
Drug-coated balloon
DES
Drug-eluting stent
ELCA
Excimer laser coronary angioplasty
ISR
In-stent restenosis
LAD
Left anterior descending artery
OCT
Optical coherence tomography
PCI
Percutaneous coronary intervention
Figure legends
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Fig. 1A
Coronary angiography showing a hazy lesion in the mid-LAD.
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Fig. 1A
1–3: OCT images demonstrating a striped, low-attenuation plaque protruding into the stent lumen.
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Fig. 1B
Post-excimer laser OCT showing partial reduction of the protruding plaque.
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Fig. 1C
Final angiographic result after DCB and kissing balloon inflation.
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Fig. 1D
, D1–3: Final OCT images showing adequate lesion expansion and plaque compression.
Declarations
Ethics approval and consent to participate
Ethical approval was waived for this case report by the Institutional Review Board of Matsuyama Red Cross Hospital, as formal IRB approval is not required for single case reports in our institution.
Consent for publication
Written informed consent was obtained from the patient for publication of this case report and associated images.
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Funding
None.
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Author Contribution
N.O. performed the intervention and drafted the manuscript. H.M. and K.M. contributed to patient care and critically revised the manuscript. All authors approved the final version.
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Data Availability
The authors confirm that the data supporting the finding of this study are available within the article.
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Acknowledgement
The authors thank the catheterization laboratory staff for their assistance during the procedure.
References
1.
Otsuka F, Byrne RA, Yahagi K, Mori H, Ladich E, Fowler DR, et al. Neoatherosclerosis: overview of histopathologic findings and implications for clinical outcomes. Eur Heart J. 2015;36(32):2147–59. doi:10.1093/eurheartj/ehv205.
2.
Hoshino M, Yonetsu T, Hada M, Sugiyama T, Yamaguchi T, Kakuta T. Neointimal remodeling following drug-coated balloon angioplasty: insights from optical coherence tomography. Ther Adv Cardiovasc Dis. 2023;17:17539447231199660. doi:10.1177/17539447231199660.
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Jinnouchi H, Kuramitsu S, Shinozaki T, Tomoi Y, Hiromasa T, Kobayashi Y, et al. Difference of tissue characteristics between early and late restenosis after second-generation drug-eluting stent implantation: an optical coherence tomography study. Circ J. 2017;81(4):450–7. doi:10.1253/circj.CJ-16-1069.
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