Clinical Experience of a Novel Optical Coherence Tomography-Guided Coronary Chronic Total Occlusion Re-Entry Device

We demonstrated a first-in-human case of successful antegrade dissection and re-entry using an image-guided re-entry catheter that enables real-time high-resolution visualization with graphical augmentation, and precision steering and advancement of a guidewire. The total time from over-the-wire deployment in the proximity of the distal cap to successful re-entry was <20 minutes. (Level of Difficulty: Advanced.)

Contemporary ADR technique often involves using a stiff wire to "stick and drive" for re-entry into the true lumen.However, this is not always successful, especially in the setting of compressed true lumen from the extraplaque space hematoma.In such cases, a "stick and swap" technique is often used whereby multiple fenestrations are made with a sharp wire, followed by a polymer-jacketed wire to wire the true lumen.We followed the same principles for ADR with this device.
If the "stick and drive" with the sharp wire was unsuccessful, our next step would have been to perform a

FOLLOW-UP
The patient did well after the procedure and did not experience any periprocedural or in-hospital adverse events.At the 30-day follow-up visit, he had experienced a significant improvement in symptoms and was free of angina.

INVESTIGATIONS 4 ,
Dual coronary angiography showed a mid-LAD CTO with tapered proximal cap (Figure1A), occlusion length of >20 mm, and calcification within the CTO segment (J-CTO score of 2) (Figure1B, Video 1).MANAGEMENTAn antegrade wire escalation (AWE) strategy was initially used; however, a polymer-jacketed soft-tip guidewire (Gladius Mongo, Asahi Intecc) was noted to be in the extraplaque space (Figure2, Video 2).Parallel wiring was also attempted with multiple guidewires, but this was unsuccessful in wiring the distal true lumen.We therefore proceeded with antegrade dissection and re-entry (ADR) using the novel imageguided re-entry catheter (The Acolyte, Simpson Interventions, Inc.) (Figures 3A to 3D).The catheter was advanced over a silicone-coated 12-gf guidewire (Miraclebros 12, Asahi Intecc) past the distal cap to the re-entry zone in the extraplaque space (Figure Video 3).Retrograde contrast material injection showed poor distal target visualization caused by extraplaque hematoma formation.Using augmented real-time optical coherence tomography (OCT) image guidance, a pulsating artery with blood flow was visualized past the distal cap of the CTO from the extraplaque space (at 5 o'clock in the OCT image/clip) (Figure 5A, Video 4).The pulsating true lumen was observed as a temporally alternating optically scattering medium-blood flow from collateral arteriesoccupying a cross-sectional area opposing the direction of the layered adventitia and perivascular structure, at the patient's heart rate.The catheter was then torqued/rotated to redirect the exit ramp overlay away from the adventitia (10 to 1 o'clock in the OCT image/clip) and toward the true lumen at 5 o'clock in the OCT image/clip (Figure 5B, Video 4).The "exit ramp overlay" or "ramp overlay" is a graphical augmentation consisting of 2 redline projections and a blue circle reference that are updated in real time over the OCT images during the procedure.The redline projections of the ramp overlay represent the direction or trajectory of the guidewire exiting the ramp leading to a side port just proximal to the distal tip of the catheter; this provides real-time information to the operator to enable him/her to steer a guidewire in the direction of the true lumen for reentry.A hydrophilic-coated 20-gf guidewire (Astato XS 20, Asahi Intecc) was then advanced through the dedicated re-entry port exit ramp (Figures 5Ci and 5Cii) to successfully re-enter the true lumen in the mid LAD.The guidewire position in the true lumen was confirmed by angiography and OCT imaging (Figures 5Di and 5Dii, Video 4).Figure 6 shows the final

FIGURE 1
FIGURE 1 Angiographic View

FIGURE 2
FIGURE 2 Angiographic View

FIGURE 3
FIGURE 3 A 4-F Image-Guided Re-entry Catheter J A C C : C A S E R E P O R T S , V O L . 2 6 , 2 0 2 3 associated with lower technical success rates and higher in-hospital rates of major adverse cardiac events, contrast volume, radiation dose, and procedure time.4,5The study was approved by a research ethics committee.The patient provided signed ethics committee-approved informed consent.In this study, we demonstrate the use of the novel 4-F OCT imageguided re-entry catheter (Figure3) in a first-inhuman case of contemporary ADR that enables realtime high-resolution visualization with graphical augmentation, precision steering, and advancement of a guidewire for re-entry (Figure5, Video 4).The OCT imaging element is situated/integrated within an imaging lumen of the re-entry catheter.The catheter is advanced over the wire to the intraplaque or extraplaque space depending on the position of the guidewire within the vessel.Aside from its high resolution enabling clear visualization of layered structures, plaque, and pulsating true lumen, it is worth noting that the utility of OCT in an occluded artery and extraplaque space was visually optimal, inasmuch as blood flow was minimal in the tight space occupied by a 4-F catheter, including when a subintimal hematoma was present.The image-guided reentry catheter provided for minimal flushing (saline or contrast material) to remove blood (eg, optical scattering media) surrounding the imaging element; saline or contrast material flushed through the imaging element was re-routed to exit 10 millimeters proximal to the catheter tip, which displaced the blood outside the catheter adjacent to the imaging element in order to reduce the risk of hydrodissection.This eliminates the need for contrast or saline flush through the guiding catheter and therefore minimizes the propagation of hydraulic dissection.A 3-way stopcock was used with the flush port to maintain pressure from backflow, keeping blood away from the surrounding of the imaging element.In future embodiments, subintimal aspiration could further enhance the performance of this image-guided re-entry catheter.

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stick and swap," for instance, with an Astato XS 20 (Asahi Intecc) followed by a Pilot 200 wire (Abbott Vascular).The image-guided re-entry catheter is the first vascular imaging system to have "self-awareness" with real-time OCT-based augmentation, which provides orientation information of the catheter relative to vascular morphology (eg, true lumen, adventitia, perivascular structure, calcified nodule), enabling the user to directionally control the coronary guidewire for re-entry.This real-time image-guided re-entry helps overcome challenges posed by extraplaque hematoma formation and subsequent loss of distal vessel visualization.The high resolution provides clear morphologic details in conjunction with software augmentation for ease of use, representing a significant advancement over current device-based re-entry approaches and intravascular ultrasoundguided techniques.The Central Illustration describes the utility of the image-guided re-entry catheter during CTO PCI, with realtime augmentation to aid in re-directing a guidewire from the extraplaque space into the true lumen.

FIGURE 4
FIGURE 4 Angiographic View

FIGURE 5
FIGURE 5 Optical Coherence Tomography Imaging View

FIGURE 6
FIGURE 6 Angiographic View

FIGURE 5
FIGURE 5 ContinuedOCT was initiated with real-time ramp overlay augmentation (redline projections with an accompanying blue circle) enabled.The ramp overlay augmentation indicates the side port orientation from which guidewire advancement would be exiting in between the 2 redline projections of the overlay.The blue circle, which is part of the ramp overlay, provides the operator a reference to gauge the accuracy of software/AI inference of the ramp overlay graphics; the ramp overlay is most accurate when the blue circle is aligned with the indicator lumen (when they are concentric on top of each other, see Figure3Dfor indicator lumen).If the blue circle is qualitatively offset against the indicator lumen, the ramp overlay including the 2 redline projections are offset to the side port exit accordingly by the same amount.In this view (A), which also corresponds to angiogram in Figure4, the ramp overlay is pointing in the direction of the adventitia/perivascular structure (orange arrow pointing to fibrous/honeycomb layer structure from 10 to 1 o'clock), and the true lumen is on the opposing side (green arrow).In B, the catheter was torqued/rotated to redirect the ramp overlay augmentation away from the adventitia/perivascular structure, in the opposing direction with the overlay now in alignment with the true lumen (green arrow pointing to crescent dark shape at 5 o'clock).In this view, the true lumen of the LAD was seen pulsating in real time and in the recorded video clip (Video 4).(Ci) A hydrophilic-coated 20-gf guidewire was advanced through the side port, seen here with the guidewire (blue arrow pointing to bright crescent-shaped object) exiting the side port in between the 2 redline projections of the ramp overlay; The corresponding angiogram (Cii) shows the guidewire exiting the exit port; the hydrophilic-coated 20-gf guidewire was used to "stick and drive."(Di) Optical coherence tomography (OCT) images confirmed re-entry, showing guidewire (blue arrow, bright crescent-shaped object) within the pulsating true lumen (green arrow).(Dii) Angiographic view confirming guidewire position in the true lumen.For video recording of OCT imaging, see Video 4.