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

Successful revascularization of coronary occlusion due to lotus root-like plaques by IVUS-based real-time three-dimensional wiring using the tip detection method in a patient with cardiac arrest

A 32-year-old man, who was treated for T-cell lymphoma, presented in cardiac arrest. He had been treated for heart failure with reduced ejection fraction. Veno-arterial extracorporeal membrane oxygenation was initiated immediately. We diagnosed him as non-ST elevated myocardial infarction. Coronary angiography demonstrated the occlusion of the trifurcation in the proximal left anterior descending artery (LAD). We failed to advance the first guidewire into the distal LAD by angio-based conventional wiring. Intravascular ultrasonography (IVUS) of the proximal diagonal branch revealed two diaphragms separating the distal lumen without connection, which looks like lotus root-like appearance. We quickly penetrated the plaque using IVUS-based real-time 3D wiring using the tip detection method. The contrast injection via the microcatheter showed the distal diagonal branch (D2). After the balloon dilation in D2, IVUS image revealed a torn plaque between D2 and the distal LAD. Subsequently we advanced the guidewire to the distal LAD using IVUS-based real-time 3D wiring using the tip detection method through the tear of the plaque. Finally, we successfully performed the revascularization of LAD in a preferable procedure time. The patient recovered well and was discharged 39 days after cardiac arrest. This case highlights the efficacy of IVUS-based real-time 3D wiring using the tip detection method even in the emergent and challenging situation.

Tip detection-antegrade dissection and re-entry (TD-ADR) with integrated fluoroscopic and intravascular ultrasound images in chronic total occlusion: first case report of integrated TD-ADR technique

Background

Tip detection-antegrade dissection and re-entry (TD-ADR) technique allows operators to accurately observe both guidewire tip direction and a true lumen in chronic total occlusion (CTO) lesions, while the torque direction of the guidewire on IVUS images does not invariably correspond to that on fluoroscopic images.

Case summary

A 41-year-old man with hypertension who smokes presented with sudden onset of dyspnoea, acute heart failure, and ischaemic findings on electrocardiogram; we performed percutaneous coronary intervention (PCI) for a sub-totally occluded mid-left anterior descending artery lesion. All antegrade wiring attempts failed to enter the distal true lumen followed by subintimal tracking and re-entry technique. Since the lesion re-occluded the next day, we treated the lesion using a novel TD-ADR technique, termed the 'integrated TD-ADR', because of no interventional retrograde channel. This method integrates fluoroscopic and intravascular ultrasound (IVUS) images, ensuring congruence in the torque direction of the guidewire across both modalities and enabling vertical puncture of the stiff guidewire from the extraplaque space to the distal true lumen quickly and precisely. Final angiography showed good results. Five months later, coronary angiography showed that the lesion remained open.

Discussion

The integrated TD-ADR technique merges fluoroscopic and IVUS images, allowing operators to torque the guidewire in the same direction on both images. This approach might be more user-friendly than the original technique and has the potential to enhance the success rate of PCI in complex CTO cases. However, further investigations are warranted to address the clinical feasibility and applicability of this technique.

Tip Detection-Antegrade Dissection and Re-Entry With New Puncture Wire in CTO Intervention: Revolution Through 3D-Wiring

Background

The authors devised the tip detection (TD) method and developed AnteOwl WR intravascular ultrasound to standardize intravascular ultrasound-based 3-dimensional wiring for intraplaque tracking in chronic total occlusion (CTO)-percutaneous coronary intervention (PCI). The TD method also allowed antegrade dissection and re-entry (ADR). Combining TD-ADR with Conquest Pro 12 Sharpened Tip (CP12ST) wire, a new ADR wire with the strongest penetration force developed to date, enabled re-entry anywhere except calcification sites.

Objectives

This study investigated the efficacy and feasibility of TD-ADR by comparison of procedural outcomes with Stingray-ADR in CTO-PCI.

Methods

Twenty-seven consecutive CTO cases treated by TD-ADR with CP12ST wire between August 2021 and April 2023 and 27 consecutive CTO cases treated by Stingray-ADR with Conquest 8-20 (CP20) wire between March 2018 and July 2021 were retrospectively enrolled as the TD-ADR by CP12ST wire group and Stingray-ADR by CP20 wire group, respectively, from 4 facilities that could share technical information on these procedures.

Results

The success rate of the ADR procedure was significantly improved (27 of 27 cases [100%] vs 18 of 27 cases [67%], respectively; P = 0.002) and total procedural time was significantly reduced (median procedural time: 145.0 [Q1-Q3: 118.0-240.0] minutes vs 185.0 [Q1-Q3: 159.5-248.0] minutes, respectively; P = 0.028) in the TD-ADR by CP12ST wire group compared to the Stingray-ADR by CP20 wire group. There were few in-hospital major adverse cardiac and cerebrovascular events or no complications in either group.

Conclusions

TD-ADR by CP12ST wire can standardize highly accurate ADR in CTO-PCI.

Clinical feasibility of endovascular recanalization with intravascular ultrasound-guided wiring for chronic total occlusion of below-the-knee arteries

BACKGROUND

Revascularization with endovascular therapy (EVT) for complex below-the-knee (BTK) chronic total occlusion (CTO) remains a challenging problem. The Japanese-BTK (J-BTK) CTO score is reported as an indicator of the difficulty of BTK CTO, with the guidewire (GW) passage success rate decreasing as the grade increases. We previously reported an effective GW crossing method for the intravascular ultrasound (IVUS)-guided parallel wiring of complex BTK CTO. In this study, we investigated the feasibility of EVT using IVUS-guided wiring for BTK CTO.

MATERIALS AND METHODS

This single center, retrospective study analyzed 65 consecutive BTK CTO vessels in which IVUS-guided wiring was attempted after the failure of a conventional antegrade wiring approach from November 2020 to November 2022. The primary endpoint was the clinical success of the target CTO vessel. The secondary endpoints were the GW success rate per grade based on the J-BTK CTO score, number of GW used for CTO crossing, fluoroscopy time, and complications.

RESULTS

Target vessels were the anterior tibial artery (66.2% of cases), peroneal artery (9.2%), and posterior tibial artery (24.6%). Blunt type CTO entry was performed in 55.4% of cases, calcification of entry was observed in 24.6% of cases, the mean occlusion length was 228.2 ± 93.7 mm, mean reference vessel diameter was 2.1 ± 0.71 mm, and outflow was absent in 38.5% of cases. J-BTK CTO scores of 0/1 (grade A), 2/3 (grade B), 4/5 (grade C), and 6 (grade D) were seen in 18.5%, 43.1%, 36.3%, and 1.5% of cases, respectively. The clinical success rate was 95.4%. The GW success rate by J-BTK CTO grade was as follows: grade A (100%), B (100%), C (91.7%), and D (0%). The mean number of GW used was 3.4 ± 1.4, the mean fluoroscopy time was 72.3 ± 32.5 min, and complications occurred in 7.7% of cases.

CONCLUSION

This study showed a very high clinical success rate despite the difficulty of BTK CTO. IVUS-guided EVT might be a feasible strategy for complex BTK CTO.

Guide extension proximal locking method: standardization of maximum backup force in percutaneous coronary intervention

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.

The role of intravascular imaging in chronic total occlusion percutaneous coronary intervention

Chronic total occlusions (CTOs) represent the most complex subset of coronary artery disease and therefore careful planning of CTO percutaneous coronary recanalization (PCI) strategy is of paramount importance aiming to achieve procedural success, and improve patient's safety and post CTO PCI outcomes. Intravascular imaging has an essential role in facilitating CTO PCΙ. First, intravascular ultrasound (IVUS), due to its higher penetration depth compared to optical coherence tomography (OCT), and the additional capacity of real-time imaging without need for contrast injection is considered the preferred imaging modality for CTO PCI. Secondly, IVUS can be used to resolve proximal cap ambiguity, facilitate wire re-entry when dissection and re-entry strategies are applied and most importantly to guide stent deployment and optimization post implantation. The role of OCT during CTO PCI is currently limited to stent sizing and optimization, however, due to its high spatial resolution, OCT is ideal for detecting stent edge dissections and strut malapposition. In this review, we describe the use of intravascular imaging for lesion crossing, plaque characterization and wire tracking, extra- or intra-plaque, and stent sizing and optimization during CTO PCI and summarize the findings of the major studies in this field.

A simple mathematical method to identify optimal biplane fluoroscopic angulations for chronic total occlusion percutaneous coronary intervention using CT angiography

Background

The concept of three-dimensional (3D) wiring for chronic total occlusion (CTO) percutaneous coronary intervention (PCI) is now widely accepted among coronary interventionalists. The 3 axes, i.e., the 2 X-ray beams and the CTO segment, should intersect with each other at as close to a right angle as possible. However, how to specify optimal fluoroscopic angulations for a given CTO segment has not been well established.

Aims

We aimed to develop a simple and practical method to identify optimal fluoroscopic angulations for CTO PCI.

Methods

A CTO vector can be derived from slab maximum intensity projection (MIP) images of coronary computed tomography (CT) angiography. Using trigonometric functions, the inner product of vectors and the equation of a plane, we calculated 2 fluoroscopic vectors perpendicular to each other and to the CTO vector.

Results

We applied this method to a patient with mid-left circumflex CTO and translated the resulting fluoroscopic vectors into optimal fluoroscopic angulations. To facilitate its use, we developed a calculator using spreadsheet software that can output optimal fluoroscopic angulations within a practical range by inputting the x, y, and z components of the CTO vector. This approach also helps to minimise dead angles in biplane fluoroscopy.

Conclusions

This method has the potential to make CTO PCI safer and easier, without requiring dedicated equipment or software. Its effectiveness should be validated in clinical practice.

Efficacy of Intravascular Ultrasound-Based 3D Wiring Using the Tip Detection Method for CTO Intervention

To perform intravascular ultrasound (IVUS)-based real-time 3-dimensional wiring in chronic total occlusion percutaneous coronary intervention, we devised a tip detection method and developed AnteOwl WR (AO)-IVUS, which is an upgraded version of Navifocus WR (Navi)-IVUS with an added pull back transducer system. We compared the procedural outcomes of AO-IVUS-based 3-dimensional wiring using the tip detection method (n = 30) and Navi-IVUS-based conventional wiring (n = 17) in chronic total occlusion percutaneous coronary intervention. The success rate of IVUS-guided wiring was markedly improved in the AO-IVUS group compared with the Navi-IVUS group (93% vs 59% of cases, respectively; P = 0.007). In cases of successful IVUS-guided wiring, the IVUS-guided wiring time was markedly improved in the AO-IVUS group compared with the Navi-IVUS group (9 ± 8 minutes vs 24 ± 26 minutes, respectively; P = 0.001). There were 2 successful cases of tip detection-antegrade dissection and re-entry in the AO-IVUS group.

Clinical effective use of Conquest Pro 12 Sharpened Tip for chronic total occlusion intervention: A series of three case reports

A new chronic total occlusion (CTO) guidewire, Conquest Pro 12 Sharpened Tip (CP12ST), has a stronger penetration force than the original CP12 and a deflection effect that it does not have. The CP12ST enables us to advance into hard plaque that has not ever penetrated, which might change CTO treatment as shown in three cases.

Tip detection-antegrade dissection and reentry using intravascular ultrasound in chronic total occlusion intervention: first human case report

Background

It has been considered impossible to perform antegrade dissection and reentry (ADR) by simply puncturing with a guidewire using the intravascular ultrasound (IVUS) observation without the support of the Stingray system.

Case summary

A 78-year-old man suffered from effort angina pectoris due to a chronic total occlusion (CTO) lesion in the left circumflex coronary artery. A retry percutaneous coronary intervention for the CTO lesion was attempted at our hospital. The J-CTO score was 3. The first guidewire entered the subintimal space. We moved onto Stingray-ADR using the angiographic observation, but the guidewire could not be led into the true lumen. AnteOwl WR-IVUS (AO-IVUS) observation revealed a distal true lumen in which the inner lumen was maintained 5 mm beyond the CTO exit. We decided to perform the tip detection-ADR using the AO-IVUS observation. The tip detection method allowed the tip of the penetration wire to puncture the wall between the subintima and the true lumen in an exactly vertical direction, resulting in the successful creation of a reentry point. The CTO lesion was dilated with one drug-eluting stent, and normal antegrade blood flow was achieved.

Discussion

Since the tip detection method enables accurate punctures, it may allow for ADR by simply puncturing using a guidewire. Due to this method being performed using the IVUS observation, it is likely more reliable than Stingray-ADR using the angiographic observation.

Parallel Wiring Using a Single Intravascular Ultrasound Catheter with Double Rapid Exchange Lumens Technique for Chronic Total Occlusions in Peripheral Artery Disease

PURPOSE

To describe a parallel wiring using a single intravascular ultrasound catheter with double rapid exchange lumens (PASSABLE) technique for peripheral CTOs.

TECHNIQUE

The technique is demonstrated in a 73-year-old patient with CTOs of the superficial femoral and popliteal artery. Intravascular ultrasound (IVUS) examination revealed the first guidewire was advanced to the intramedial space of the popliteal artery. Following insertion of the first guidewire into only the distal rapid exchange lumen of the IVUS catheter and a second guidewire into the proximal rapid exchange lumen, a guidewire torquer was passed over it and tightened close to an exit port of the proximal rapid exchange lumen to prevent it from exiting an entry port while advancing the IVUS catheter. The IVUS catheter was advanced to the intraplaque region using only the distal rapid exchange lumen and the second guidewire was then advanced to the intraplaque region under IVUS guidance. The IVUS-guided wiring using the second guidewire on both the distal and proximal rapid exchange lumen was continued and resulted in a successful guidewire crossing into the distal true lumen.

CONCLUSION

This novel technique may prove beneficial in enabling operators to perform IVUS-guided parallel wiring more easily and efficiently.

Efficacy of navigating through the intraplaque route using AnteOwl WR intravascular ultrasound in femoropopliteal chronic total occlusion

BACKGROUND

There is no consensus on the optimal guidewire passage route for femoropopliteal (FP) chronic total occlusion (CTO). If intraplaque wiring can be performed, a stent-less strategy using a drug-coated balloon can be realized even with FP CTO, and there is a high possibility that good expansion can be obtained even when stent deployment is performed. AnteOwl WR (AnteOwl) is a novel intravascular ultrasound (IVUS) device useful for navigating the second guidewire into the intraplaque route under IVUS observation from the subintimal space. Here, we describe representative cases of FP CTO in which CTO-specific IVUS was extremely useful.

CASE PRESENTATION

Case 1 involved a 79-year-old man with total occlusion of the left superficial femoral artery (SFA). We used a contralateral antegrade approach, but the guidewire was advanced into the subintimal space. We advanced AnteOwl into the CTO. By utilizing the asymmetric structure of the transducer and the IVUS wire, we were able to reflect the positional relationship among the IVUS transducer, IVUS wire, and target plaque onto the angiographic image. By aiming the wiring in that direction, we succeeded in traversing the center of the plaque and finally succeeded in obtaining good expansion using the drug-coated balloon. Case 2 involved a 76-year-old woman with total occlusion from the SFA to the popliteal artery. We used an ipsilateral antegrade approach. When AnteOwl was placed on the wire and advanced to the popliteal artery, the subintimal space in the middle of the SFA could be visualized. We employed an IVUS-guided parallel wiring technique and succeeded in passing through all intraplaque routes. Although the CTO was long, we could easily advance through the intraplaque route by reflecting the information obtained from AnteOwl in angiography.

CONCLUSIONS

AnteOwl is an effective IVUS for FP CTO and facilitates a complex IVUS-guided procedure.

Intravascular Ultrasound in Chronic Total Occlusion Percutaneous Coronary Intervention: Solving Ambiguity and Improving Durability

Chronic total occlusions remain among the most technically challenging lesions to treat percutaneously. Limitations of 2-dimensional angiography may further hinder successful treatment of these lesions. Intrasvascular ultrasound has a key role in percutaneous recanalization for a chronic total occlusion by providing key lesion characteristics, facilitating guidewire crossing, elucidating the intraplaque or extralaque path of the guidewire, optimizing lesion preparation, guiding stenting and identifying suboptimal results. Live visualization of the guidewire during crossing may reduce extraplaque wire tracking. This review describes the practical uses of intravascular imaging for commonly encountered scenarios when treating chronic total occlusions.

The role of intravascular ultrasound in percutaneous coronary intervention of complex coronary lesions

Intravascular ultrasound (IVUS) is a catheter-based coronary imaging technique. It utilises the emission & subsequent detection of reflected high frequency (30-60 MHz) sound waves to create high resolution, cross-sectional images of the coronary artery. IVUS has been the cornerstone of intracoronary imaging for more than two decades. When compared to the invasive coronary angiogram which studies only the silhouette of the contrast-filled artery lumen, IVUS also crucially images the vessel wall. Because of this capability, IVUS has greatly facilitated understanding of the coronary atherosclerosis process. Such insights from IVUS reveal how commonly and extensively plain angiography underestimates the true extent of coronary plaque, the characteristics of plaques prone to rupture and cause acute coronary syndromes (lipid rich, thin cap atheroma), and a realisation of the widespread occurrence of vessel remodelling in response to atherosclerosis. Similarly, IVUS has historically provided salutary mechanistic insights that have guided many of the incremental advances in the techniques of percutaneous coronary intervention (PCI). Examples include mechanisms of in-stent restenosis, and the importance of high-pressure post-dilatation of stents to ensure adequate stent apposition and thereby reduce the occurrence of stent thrombosis. IVUS also greatly facilitates the choice of correct diameter and length of stent to implant. Overall, a compelling body of evidence indicates that use of intravascular ultrasound in PCI helps to achieve optimal technical results and to mitigate the risk of adverse cardiac events. In this review, the role of intravascular ultrasound as an adjunct to PCI in complex coronary lesions is explored. The complex coronary situations discussed are the left main stem, ostial stenoses, bifurcation stenoses, thrombotic lesions, the chronically occluded coronary artery, and calcified coronary artery disease. By thorough review of the available evidence, we establish that the advantages of IVUS guidance are particularly evident in each of these complex CAD subsets. In particular, some consider the use of IVUS to be almost mandatory in left main PCI. A comparison with other intracoronary imaging techniques is also explored.

Latest developments in chronic total occlusion percutaneous coronary intervention

INTRODUCTION

Chronic Total Occlusion Percutaneous Coronary Intervention (CTO PCI) is now performed with high success rates and acceptable complication rates.

AREAS COVERED

We describe recent clinical and technological developments in CTO PCI from 2018 to 2020.

EXPERT OPINION

After publication of six randomized controlled trials, improving patient symptoms remains the principal indication for CTO PCI. Although good outcomes can be achieved with CTO PCI at experienced centers, success rates are significantly lower at less experienced centers, despite increased use in CTO crossing algorithms and development of novel and improved equipment and techniques.

New CTO-Specific IVUS

The newer chronic total occlusion–specific intravascular ultrasound AnteOwl WR-based 3-dimensional wiring technique using the tip detection method allowed us easily to succeed in treating chronic total occlusion lesions that were previously unsuccessfully treated using Navifocus WR intravascular ultrasound. (Level of Difficulty: Advanced.)