Vascular response and silent micro-embolization after rotational atherectomy and drug-coated balloon angioplasty: insights from micro-computed tomography and histology

A 72-year-old man with ischaemic cardiomyopathy underwent revascularization for three-vessel coronary disease under intra-aortic balloon pump support. Baseline coronary angiography showed bulky calcification extending from the left main trunk into the proximal left anterior descending artery (LAD; Panel A). Intravascular ultrasound after 1.5-mm rotational atherectomy (RA) demonstrated thick eccentric calcification with reverberation artefacts (Panel C). The lesion was then dilated with a non-slip element balloon and finalized with a drug-coated balloon (DCB). Although the final angiogram showed adequate lumen gain without slow flow (Panel B), the patient developed post-procedural ST-segment elevation and progressive heart failure, dying 1 month later. Post-mortem coronary histology (Panels D and E) and micro-computed tomography (micro-CT; Panel F; see Supplementary data online, Movie S1) showed effective modification of sheet-like and nodular calcification, with a smooth luminal surface and minimal injury to the non-calcified vessel wall. Notably, the absence of significant medial tears, an established pathological trigger for restenosis in calcified lesions, may have contributed to the excellent short-term patency with DCB-only therapy. Myocardial micro-CT identified approximately 13 calcific fragments (yellow dotted circles) in the LAD territory across multiple sections, consistent with distal micro-embolization (Panels G and H, a magnified view of the white dotted box in Panel G). Myocardial histopathology demonstrated calcific material (arrow) within distal myocardial capillaries, accompanied by phagocytosing macrophages (arrowheads, Panel I). This case provides first-in-human imaging and pathological evidence of angiographically ‘silent’ distal embolization after RA-assisted DCB. These observations support a conservative atherectomy approach and heightened vigilance for distal embolic events, particularly in vulnerable patients. We used ChatGPT (OpenAI) for language editing to improve clarity and readability. The authors take full responsibility for the content. Supplementary data are available at European Heart Journal - Cardiovascular Imaging online. Author contributions: Kohei Hirobe (Writing—original draft [lead]), Sho Torii (Writing—review & editing [lead]), Yu Sato (Writing—review & editing [supporting]), Sawako Chiba (Formal analysis [supporting]), and Fumiaki Mori (Writing—review & editing [supporting]) Statement of consent: The authors confirm that written consent for submission and publication of this case report including images and associated text has been obtained from the patient in line with COPE guidance. Funding: No financial support was provided for this manuscript. All authors have no relationships relevant to the contents of this paper to disclose. Data availability: The data underlying this article are available within the article. Additional de-identified data will be shared by the corresponding author on reasonable request.