The impact of tissue characterization for in-stent restenosis with optical coherence tomography during excimer laser coronary angioplasty

We aimed to evaluate the impact of tissue characterization for in-stent restenosis (ISR) with optical computed tomography (OCT) during excimer laser coronary angioplasty (ELCA) in the drug-eluting stent (DES) era. The effect of ELCA for ISR according to differences in tissue characteristics is unclear. Fifty-three ISR lesions (7 bare metal stents and 46 drug-eluting stents) were treated with an ELCA catheter. After ELCA, balloon dilatation with either the scoring or non-compliant balloons was conducted. The procedure was completed by applying a drug-coated balloon. Tissue characterization and lumen measurement with OCT were performed thrice: (1) before percutaneous coronary intervention (PCI), (2) after ELCA, and (3) and after the procedure. Lesions were categorized into the homogenous, layered, and mixed groups. Follow-up angiograms were conducted 6–12 months after PCI. No significant differences in minimal lumen area (MLA) were observed before PCI. A significant difference was observed in MLA after ELCA among the three groups (homogeneous group: 1.75 ± 0.84 mm(2), layered group: 1.72 ± 0.45 mm(2), mixed group: 2.24 ± 0.70 mm(2), P = 0.048). Final MLA was larger in the mixed group than in the homogeneous group (P = 0.028). No significant difference was observed in binary restenosis in the follow-up angiogram (homogeneous group 55.5%, layered group 33.3%, mixed group 33.3%; P = 0.311) and the target lesion revascularization rate (homogeneous 30.0%, layered 23.8%, mixed 25.0%; P = 0.923). Tissue characterization by OCT may predict the efficacy of ELCA and balloon angioplasty for ISR during the acute phase.