Maoto Habara

BACKGROUND: Frequency-domain optical coherence tomography (FD-OCT) is a novel, high resolution intravascular imaging modality. Intravascular ultrasound (IVUS) is a widely used conventional imaging modality for achieving optimal stent deployment. The aim of this study was to evaluate the impact of FD-OCT guidance for coronary stent implantation compared with IVUS guidance. METHODS AND RESULTS: A total of 70 patients with de novo coronary artery lesions and either unstable or stable angina pectoris were enrolled in this randomized study (optical coherence tomography [OCT] group: n=35, IVUS group: n=35). In the OCT group, stent implantation was performed under FD-OCT guidance alone and final stent expansion was evaluated by IVUS. In the IVUS group, conventional IVUS guidance was used and final stent apposition was evaluated by FD-OCT. There were no significant differences regarding the procedural, fluoroscopy time, and contrast volume. Although device and clinical success rates also were similar, the visibility of vessel border was significantly lower in the OCT group (P<0.05). Minimum and mean stent area and focal and diffuse stent expansion were smaller (6.1±2.2 mm versus 7.1±2.1 mm, 7.5±2.5 versus 8.7±2.4 mm, 64.7±13.7% versus 80.3±13.4%, 84.2±15.8% versus 98.8±16.5%, P<0.05, respectively), and the frequency of significant residual reference segment stenosis at the proximal edge was higher in the OCT group (P<0.05). Incomplete apposed struts in both groups were similar (P=0.34). CONCLUSIONS: FD-OCT guidance for stent implantation was associated with smaller stent expansion and more frequent significant residual reference segment stenosis compared with conventional IVUS guidance.

OBJECTIVES: This study was performed to evaluate the acute outcomes of percutaneous coronary intervention (PCI) for chronic total occlusion (CTO) based on operator experience. BACKGROUND: Despite developments in both technology and techniques, PCI procedures for CTO's remain challenging. METHODS: A total of 3,229 eligible subjects who underwent CTO-PCI were enrolled from 56 centers by a retrograde summit using a web registry system. To compare the acute outcomes of the CTO data, 18 centers were classified as higher volume centers (HC) and 38 centers as lower volume centers (LC) depending on the CTO-PCI experience of the operator. RESULTS: The mean procedural success rate of all centers was 88.4%. The overall procedural success rate was significantly higher in HC than LC (90.6% vs. 85.6%, respectively; P < 0.0001). In addition, overall antegrade success rate was also higher in HC than LC (91.0% vs. 83.9%, respectively; P < 0.0001). Although the overall retrograde approach success rate was significantly higher in HC than LC (85.0% vs. 77.6%, respectively; P < 0.0001), there was no significant difference in that of the retrograde alone (89.0% vs. 93.7%, respectively; P = 0.051). Major in-hospital adverse events were observed in 0.53% of cases, and the rates were similar between the two groups (0.45% vs. 0.62%, respectively; P = 0.25). CONCLUSIONS: Although CTO-PCI was safe in both groups, the procedural success rate was significantly higher in HC than LC, even in this new era of CTO-PCI. This difference was attributed to the difference in the antegrade procedural success rate. © 2015 Wiley Periodicals, Inc.

BACKGROUND: Although in-stent restenosis (ISR) after bare-metal stent (BMS) implantation peaks in the early phase, very late (VL) ISR occasionally is observed beyond a few years after BMS implantation. To date, this mechanism has not been fully clarified. METHODS AND RESULTS: We compared the morphological characteristics of VL-ISR (>5 years, without restenosis within the first year) (n=43) to those of early (E) ISR (within the first year) (n=39) using optical coherence tomography (OCT). Qualitative restenotic tissue analysis included assessment of tissue structure (homogeneous or heterogeneous), presence of microvessels, disrupted intima with cavity, and intraluminal material and was performed at every 1-mm slice of the entire stent. The proportions of cross-sections with heterogeneous intima in the entire stent was significantly higher in the VL-ISR group compared to the E-ISR group (60.5±28.5% versus 5.8±11.5%, P<0.0001), with heterogeneous intima being more frequently observed at the minimum lumen area site in the VL-ISR group (90.7% versus 17.9%, P<0.0001). Disrupted intima with cavity and intraluminal material also were observed more frequently in the VL-ISR group for the entire stent (18.6% versus 0%, 20.9% versus 2.6%, P<0.03) as well as at the minimum lumen area site (13.9% versus 0%,16.2% versus 0%, P<0.03). CONCLUSIONS: The morphological characteristics of restenotic tissue in VL-ISR were different from those in E-ISR and similar to atherosclerotic plaque. In BMS, progression of the atherosclerotic process within neointima after stent implantation may be associated with VL-ISR.

AIMS: Restenosis of drug-eluting stents (DESs) might be different from that of bare metal stent restenosis in diverse ways including mechanisms and time course; however, these have not been fully examined. To gain insight into the mechanisms and time course of DES restenosis, we evaluated the characteristics of restenotic lesions of first generation DES using optical coherence tomography (OCT). METHODS AND RESULTS: We compared the morphological characteristics of early in-stent restenosis (<1 year: E-ISR, n = 43), late ISR (1-3 years: L-ISR, n = 22), and very late ISR (>3 years: VL-ISR, n = 21). OCT qualitative restenotic tissue analysis included the assessment of tissue structure [homogeneous or four types of heterogeneous intima (thin-cap fibroatheroma (TCFA)-like, layered, patchy or speckled pattern)], the presence of the peri-strut low intensity area (PLIA), microvessels, disruption with cavity, and intraluminal material and was performed at every 1 mm slice of the entire stent length. In addition to a greater trend for heterogeneous intima at the later phase, TCFA-like pattern image, intra-intima microvessels were increased from the early to the very late phase. On the other hand, the speckled pattern image was decreased from the early to the very late phase. CONCLUSION: The OCT morphological characteristics of DES restenotic tissue varied at different time-points. OCT images in early DES ISR might be associated with delayed arterial healing, and neoatherosclerosis might contribute to late catch-up phenomenon (L-ISR and VL-ISR) after DES implantation.