Abstract 12924: Morphological Mechanisms Underlying Efficacy of Paclitaxel-Coated Balloon Against Repeated In-Stent Restenosis

Abstract

Background: In-stent restenosis (ISR) has been an important issue even after percutaneous coronary intervention (PCI) with drug-eluting stents (DES). Recently, paclitaxel-coated balloon (PCB) has emerged as a potential alternative to the conventional treatment of ISR (plain balloon angioplasty [PBA]) with lower incidence of re-ISR. However, detailed mechanisms underlying the clinical efficacy of PCB have been still unknown morphologically. Methods: Consecutive 32 patients whose in-stent restenotic lesions were treated by intravascular ultrasound (IVUS)-guided PBA (n=15) or PCB (n=17). Optical coherence tomography (OCT) and angiographic follow-up was done at 9 months after PCI for ISR, and the detailed IVUS/OCT and angiographic findings were compared to elucidate the differences in qualitative and quantitative characteristics of in-stent intima between the groups. Results: Compared with PBA group, re-ISR rate was significantly lower in PCB group (24% vs. 80%, p=0.005). Although post-PCI minimum lumen angiographic diameter (MLD) and IVUS area (MLA) were comparable between the groups (2.9±0.8mm vs. 2.8±0.8mm, p=0.7; 3.5±1.1mm 2 vs. 4.1±1.0mm 2 , p=0.9, respectively), MLD and MLA at follow-up were kept significantly larger in PCB group (2.7±0.9mm vs. 1.3±1.0mm, p=0.02; 4.3±2.8mm 2 vs. 2.1±0.9mm 2 , p=0.02, respectively), mainly attributable to smaller intimal area at MLA site (1.2±0.6mm 2 vs. 4.1±2.9mm 2 , p=0.03). Interestingly, post-PCB intima was significantly regressed in spite of the progression of post-PBA intima (-1.0±1.4mm 2 vs. 0.5±1.6mm 2 , p=0.01, Figure ). In terms of OCT-derived tissue characteristics of in-stent intima, post-PCB intima was more homogeneous rather than heterogeneous/layered (homogeneous/heterogeneous/layered: 60%/27%/13% vs. 18%/41%/41%, p=0.04). Conclusion: Clinical usefulness of PCB for DES-ISR might be based on not only smaller intimal area but also more stable intimal tissue of the regressed post-PCB intima.