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We developed the smallest diameter guide-extension catheter (GUIDE PLUS® 5Fr) to enable a new technique, the guide-extension proximal locking method (GP-Lock), and assessed its efficacy in the present experimental and clinical study. Sufficient guide catheter backup is sometimes crucial for PCI. We developed the KIWAMI-Lock direct anchoring method to obtain the strongest backup force by locking a Kiwami® 4Fr child catheter (Terumo Corp. Tokyo, Japan) directly to the coronary artery by ballooning from outside the child catheter. However, this method is complicated due to the requirement for a child catheter. We compared the backup power of the GP-Lock method and other conventional methods in an experimental study and compared the procedural outcomes of 17 cases treated using the initial GP-Lock method with 17 cases using the recent KIWAMI-Lock method before GP-Lock. The GP-Lock method had the highest backup force among the methods examined (GP-Lock: 293.7 ± 10.2 g force (gf), KIWAMI-Lock: 270.4 ± 12.9 gf, side branch balloon anchoring technique: 182.7 ± 8.1 gf, respectively, P < 0.0001). The preparation time was significantly shorter for the GP-Lock group than the KIWAMI-Lock group (5.0 [4.0, 5.0] min vs. 11.0 [8.0, 13.0] min, respectively, P < 0.001). The GP-Lock method makes it possible to easily obtain the strongest backup force, which can overcome situations where devices cannot pass through, especially in complex PCI procedures., (© 2023. The Author(s) under exclusive licence to Japanese Association of Cardiovascular Intervention and Therapeutics.)

Competing Interests: Funding Support and Author Disclosures Dr Okamura has received speaker fees from Terumo. Dr Tsuchikane is a consultant for Asahi Intecc, Boston Scientific, and Kaneka. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.

Objectives: This study assessed the efficacy of the tip detection method during intravascular ultrasound (IVUS)-based 3-dimensional (3D) wiring with a new chronic total occlusion (CTO)-specific IVUS system (AnteOwl IVUS [AO-IVUS]) for CTO percutaneous coronary intervention (PCI)., Background: The study developed angiography-based 3D wiring for CTO-PCI. Previously, the authors produced a short-tip CTO-specific IVUS system (Navifocus WR IVUS [Navi-IVUS]), which has been upgraded into the AO-IVUS system by adding a pullback transducer system for IVUS-based 3D wiring., Methods: A CTO lesion 20 mm in length composed of 2.5% agar was experimentally inserted into the coronary artery of a beating heart model. The target (a microcatheter with a 0.6-mm lumen) was placed in the distal part of the CTO lesion. IVUS-guided wiring was performed to insert the guidewire into the target using the Navi-IVUS and then using the AO-IVUS 8 times each. In wiring with AO-IVUS, the IVUS-based 3D wiring using the tip detection method was performed. The crossing time and the number of punctures to the target were calculated., Results: The crossing time was significantly shortened and the number of punctures was significantly reduced in AO-IVUS-based wiring compared with Navi-IVUS-based wiring (median crossing time 80.5 s [interquartile range: 44.0 to 112.3 s] vs. 333.0 s [interquartile range: 88.8 to 790.0 s]; p = 0.036; median 1.0 puncture [interquartile range: 1.0 to 2.0 punctures] vs. 24.0 punctures [interquartile range: 5.8 to 52.5 punctures]; p = 0.001)., Conclusions: The tip detection method enables the authors to easily perform the IVUS-based 3D wiring, and the new CTO IVUS system will facilitate this method in clinical practice., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Objectives: This study sought to compare the procedural outcomes of percutaneous coronary intervention for chronic total occlusion between the periods before and after introduction of 3-dimensional (3D) wiring., Background: Previously, we reported a 3D wiring method by which the operator can construct real-time mental 3D images from 2 perpendicular angles of X-ray system monitor during percutaneous coronary intervention for chronic total occlusion., Methods: A total of 137 chronic total occlusion lesions that could not be passed by tapered soft wires in our hospital between 2012 and 2017 were retrospectively enrolled in the study., Results: Overall success rate was significantly higher in the 3D wiring group (n = 69) than the non-3D wiring group (n = 68) (98% vs. 90%, respectively; p = 0.027). In the primary antegrade cases, the first antegrade approach time was significantly shorter in the 3D wiring group than the non-3D wiring group (42 ± 29 vs. 30 ± 16 min, respectively; p = 0.01). In cases where the antegrade approach was continued throughout the procedure, the success rate was significantly higher in the 3D wiring group than the non-3D wiring group (100% vs. 89.2%, respectively; p = 0.033). Vessel perforation by the antegrade wire tended to be lower in the 3D wiring group than the non-3D wiring group (1% vs. 11%, respectively; p = 0.055)., Conclusions: 3D wiring enables accurate guidewire control, which improves the success rate of antegrade wiring and reduces the antegrade procedure time, resulting in improvement of the overall success rate., (Copyright © 2019 The Authors. Published by Elsevier Inc. All rights reserved.)

We recently reported the coronary thermodilution curve can be evaluated by analyzing the thermodilution curve obtained from a pressure sensor/thermistor-tipped guidewire, and presence of a bimodal-shaped thermodilution curve following primary percutaneous coronary intervention (pPCI) in ST-segment elevation myocardial infarction (STEMI) patients was associated with worse outcomes. This study evaluated whether the bimodal-shaped thermodilution curve predicts left ventricular (LV) remodeling after STEMI. The coronary thermodilution curve patterns were evaluated for 75 patients treated by pPCI for their first STEMI using a pressure sensor/thermistor-tipped guidewire, and classified into the three groups according to the thermodilution curve shape: narrow unimodal (n = 39), wide unimodal (n = 26), and bimodal pattern (n = 10). Echocardiography was performed at baseline and 6 months after STEMI. LV remodeling was defined as a >20 % increase in LV end-diastolic volumes (LVEDV). LVEDV at 6-month follow-up was greater in the bimodal group than in the other groups (p < 0.001). The prevalence of LV remodeling was highest in the bimodal group than in the narrow and wide unimodal groups (60, 12, and 15 %, respectively; p = 0.003). Multivariate analysis revealed a bimodal-shaped thermodilution curve as an independent predictor of the prevalence of LV remodeling. A bimodal-shaped thermodilution curve is associated with LV remodeling after STEMI. This easily assessable coronary thermodilution curve pattern is useful to predict mid-term LV remodeling for STEMI patients at the catheterization laboratory.

Background: Optical coherence tomography (OCT) is one of the tools trying to distinguish neoatherosclerosis from other neointimal tissue but its role has to be still validated. This study evaluated the diagnostic accuracy of OCT for characterization of lipid-atherosclerotic neointima following drug-eluting stent (DES) implantation., Methods: Twelve stented coronary arteries from the 7 autopsy hearts were imaged by OCT. These OCT images were compared with histology. By OCT, the morphological appearances of neointima were classified into three patterns: homogeneous pattern, heterogeneous pattern with visible strut, or heterogeneous pattern with invisible strut., Results: Of 21 histological cross-sections, 6 were categorized as homogeneous patterns (29%), 11 as heterogeneous patterns with visible stent strut (52%), and 4 as heterogeneous patterns with invisible stent strut (19%). All homogeneous patterns were composed of smooth muscle cells with collagen fibers. The heterogeneous patterns with visible stent strut included proteoglycan-rich myxomatous matrix and calcium deposition. On the other hand, the heterogeneous patterns with invisible stent strut comprised atheromatous tissue, including a large amount of foam cell accumulation (25%) or large fibroatheroma/necrotic core (75%) inside the stent struts within neointima. The optical attenuation coefficient was highest in the heterogeneous pattern with invisible stent strut due to scattering of light by atheromatous tissue., Conclusion: The heterogeneous patterns with invisible stent strut on OCT imaging identify the presence of lipid-atherosclerotic tissue within neointima after DES. This may suggest the potential capability of OCT based on visualization of stent struts for discriminating atheromatous formation within neointima from other neointimal tissue., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)