A 74-year-old male. He originally underwentcoronary artery bypass grafting (SVG-LAD, SVG-RCA) 33 years prior for an oldanterior wall myocardial infarction. Nineteen years ago, a 2.5 mmsirolimus-eluting stent was placed in LAD #6 for occlusion of the SVG-LADbypass graft. Subsequently, in-stent restenosis developed at the same site.

PCI was performed using DCB combined with a cuttingballoon and OAS, but poor stent expansion of the sirolimus-eluting stent wasalso present, leading to a total of six episodes of restenosis.

CAGshowed in stent restenosis in LAD #6, prompting a decision to perform PCI. InitialIVUS and OCT examination of the LAD revealed an in-stent lesion with poor stentexpansion due to an extrastent calcified lesion. Attempts to expand the lesionusing a 3 mm scoring balloon resulted in residual indentation. This time,dilation with an Intervascular Lithotripsy (IVL) 3.0 mm achieved stentexpansion at the site of poor expansion. OCT also confirmed expansion at thissite. Additional dilation with a 3 mm scoring balloon secured the lumen, andthe procedure was completed with drug coating using a drug-coated balloon.

The use of IVL in in-stentrestenosis remains off-label and has been described in case reports and smallcase series. Whilewe confirmed its effectiveness in this case, we have also encountered cases atour institution where efficacy could not be confirmed. We report the results ofa comparative analysis of these cases, including a brief literature review.