Calcified Nodule Protruding Into the Lumen Through Stent Struts: An In Vivo OCT Analysis

We observed a calcified nodule (CN) protruding into the coronary lumen through the stent struts of an in-stent restenosis (ISR) lesion in detail using optical coherent tomography (OCT). The patient was a 56-year-old Japanese male on regular hemodialysis for his end-stage renal disease who had multiple coronary risk factors. He previously underwent percutaneous coronary intervention (PCI) for the middle left anterior descending artery and a drug-eluting stent was implanted. OCT showed a CN in the culprit lesion. He underwent coronary angiography 9 months later, and an ISR lesion was observed. Re-PCI was done, and a drug-coated balloon was used. OCT showed a CN protruding into the coronary lumen through the stent struts in the ISR lesion. Although this phenomenon was previously reported in a pathological study, the observation of a CN protruding through stent struts by in vivo OCT has been rarely demonstrated previously. The present study provides support for the previous pathological report, and demonstrates a useful application of OCT imaging that can help in the treatment of ISR lesions.