Tip Detection Method Using the New IVUS Facilitates the 3-Dimensional Wiring Technique for CTO Intervention

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.