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.

The Characteristics of Primary Retrograde Approach Selection for Native Coronary Chronic Occlusion With Short Occlusion Length from the Japanese CTO-PCI Expert Registry

Although the coronary chronic total occlusion (CTO) crossing algorithm has been published, the characteristics associated with the first strategy selection for short-length lesions <20 mm is still debatable. This study aimed to determine the characteristics associated with primary retrograde approach (PRA) for native CTO with short occlusion length in percutaneous coronary intervention (PCI). Between January 2014 and December 2021, we examined data on 4,088 lesions in the Japanese CTO-PCI Expert Registry with occlusion lengths <20 mm. Then, the characteristics for short-length CTO, which was performed by way of the PRA, were assessed. PRA was performed in 785 patients (19.2%). The guidewire success rate was 93.6%, and the technical success rate was 91.3%. Previous coronary artery bypass grafting, chronic kidney disease, and 6 lesion/anatomic characteristics (i.e., blunt stump, distal runoff <1 mm, CTO lesion tortuosity, reattempt procedures, ostial location, and the presence of collateral channel grade 2) were associated with PRA (p <0.05). Moreover, hemodialysis was an independent factor of unsuccessful anterograde guidewire crossing, along with distal runoff <1 mm, the existence of calcification, and CTO lesion tortuosity (all p <0.05). In clinical settings, these independent factors for PRA in short-length CTO can help in selecting the CTO-PCI strategy.

Retrograde Coronary Chronic Total Occlusion Intervention (JR-CTO) Score: From the Japanese CTO-PCI Expert Registry

BACKGROUND

Despite the effectiveness of the retrograde approach for chronic total occlusion (CTO) lesions, there are no standardized tools to predict the success of retrograde percutaneous coronary intervention (PCI).

OBJECTIVES

The objective of this study was to develop a prediction tool to identify CTO lesions that will achieve successful retrograde PCI.

METHODS

This study evaluated data from 2,374 patients who underwent primary retrograde CTO-PCI and were enrolled in the Japanese CTO-PCI Expert Registry between January 2016 and December 2022 (NCT01889459). All observations were randomly assigned to the derivation and validation cohorts at a 2:1 ratio. The prediction score for guidewire failure in retrograde CTO-PCI was determined by assigning 1 point for each factor and summing all accrued points.

RESULTS

The JR-CTO score (moderate-severe calcification, tortuosity, Werner collateral connection grade ≤1, and nonseptal collateral channel) demonstrated a C-statistic for guidewire failure of 0.72 (95% CI: 0.67-0.76) and 0.71 (95% CI: 0.64-0.77) in the derivation and validation cohorts, respectively. Patients with lower scores had higher guidewire and technical success rates and decreased guidewire crossing time and procedural time (P < 0.01).

CONCLUSIONS

The JR-CTO (Japanese Retrograde Chronic Total Occlusion) score, a simple 4-item score that predicts successful guidewire crossing in patients undergoing retrograde CTO-PCI, has the potential to support clinical decision-making for the retrograde approach.

First successful implementation of subintimal transcatheter withdrawal technique in intravascular ultrasound-guided tip detection antegrade dissection and reentry: a case report

Background

Antegrade dissection and reentry (ADR) is an effective technique for wire passage in chronic total occlusion (CTO), and in recent years, the effectiveness of intravascular ultrasound (IVUS)-guided tip detection (TD)-ADR has been reported. However, the expansion of the subintimal space serves as a significant obstacle to the success of ADR, posing a limitation to the procedure.

Case summary

We present the first case of using IVUS-guided TD-ADR with the subintimal transcatheter withdrawal (STRAW) technique. The patient was a 68-year-old Asian female with effort angina pectoris and a CTO in the middle section of the right coronary artery (RCA). Two previous attempts at percutaneous coronary intervention (PCI) for the RCA at another hospital were unsuccessful. During the third attempt PCI, the antegrade wire migrated into the subintimal space. To address this, we performed IVUS-guided TD-ADR using the Conquest Pro 12 Sharpened Tip (CP12ST; Asahi Intecc, Aichi, Japan) wire. However, due to the expansion of the subintimal space, we were unable to puncture the true lumen. To reduce the subintimal space, we employed the STRAW technique, which allowed successful puncture of the true lumen using the CP12ST wire. Finally, stenting was performed, resulting in satisfactory antegrade blood flow.

Discussion

Intravascular ultrasound-guided TD provides accurate guidance for puncturing in ADR procedures, but the expansion of the subintimal space remains a significant challenge. The STRAW technique offers a solution by reducing the subintimal space and enabling successful puncture of the true lumen during IVUS-guided TD-ADR.

New Angiographic Difficulty Score for First-Attempt Chronic Total Occlusion in the 3 Major Coronary Arteries

BACKGROUND

Chronic total occlusion (CTO) percutaneous coronary intervention (PCI) is still challenging due to complex lesion morphology. Success rates may vary among the 3 major coronary arteries, influenced by clinical and angiographic characteristics.

OBJECTIVES

This study sought to evaluate the differences in the predictors of unsuccessful PCI in first-attempt CTO lesions of the 3 major coronary arteries compared with the J-CTO (Japanese CTO) score.

METHODS

This study assessed 6,408 first-attempt CTO patients from the Japanese CTO-PCI expert registry between January 2014 and December 2021, randomly assigned to derivation and validation sets. Difficulty scores for each artery were determined by assigning points to predictive unsuccessful factors.

RESULTS

The CTO lesions were distributed as follows: left anterior descending coronary artery: 2,245 (35%), left circumflex coronary artery: 1,131 (18%), and right coronary artery (RCA): 3,032 (47%). Regarding success rates, left circumflex coronary artery CTO had the lowest procedural success rate (90%) followed by RCA CTO (92%) and left anterior descending coronary artery CTO (94%). RCA CTO was significantly longer and more severely angulated, requiring more often the retrograde approach. A multivariate logistic analysis revealed that predictors of failed PCI were different in CTO lesions among the 3 major coronary arteries, respectively. Moreover, our difficulty score for RCA CTO was superior to the J-CTO score in predicting unsuccessful PCI.

CONCLUSIONS

Clinical and angiographic differences might explain the discrepancies of success rates in CTO lesions among the 3 major coronary arteries. Our novel difficulty score was comparable to the J-CTO score in predicting unsuccessful CTO-PCI with a superior discriminatory capacity.

Chronic total occlusion of the left circumflex coronary artery with collateral channels from the bronchial artery: a case report

Background

Chronic total occlusion (CTO) lesions contain various collateral channels. Only a few reports have described CTO with collateral channels from the bronchial arteries.

Case summary

Herein, we report the case of a 59-year-old man with a left circumflex (LCX) coronary artery CTO with collateral channels from the bronchial arteries. The J-CTO score was 1. After confirming myocardial viability and myocardial ischaemia using a stress myocardial perfusion imaging test, we performed percutaneous coronary intervention for the CTO lesion. Successful revascularization was achieved by adopting the antegrade approach with the angiogram guidance of distal visualization using the bronchial artery.

Discussion

Notably, there are no other reports of LCX CTO with collateral channels from the bronchial artery. Distal visualization of the distal true lumen is essential for the success of the antegrade approach. Furthermore, appropriate distal visualization helps to avoid unnecessary retrograde approaches and reduce complications.

A case report of virtual reality-guided percutaneous coronary intervention for anomalous origin of right coronary artery chronic total occlusion

Background

Engagement of the guiding catheter (GC) for the coronary artery is sometimes difficult, depending on the patient's anatomy. The most suitable GC before percutaneous coronary intervention (PCI) in individual cases has not been determined yet.

Case summary

An 81-year-old woman who had a right coronary artery chronic total occlusion had difficulty to engage the catheter for the right coronary artery in the first examination. Virtual reality (VR)-guided GC simulation before PCI using cardiac computed tomography (CT) could overcome the difficulty of GC engagement for the coronary artery and achieve procedure success.

Discussion

VR-guided GC simulation has the potential to solve the catheter approach difficulty for any cardiovascular intervention.

Impact of minimum contrast media volumes during percutaneous coronary intervention for chronic total occlusion lesion

Contrast media exposure is associated with contrast-induced nephropathy (CIN) following percutaneous coronary intervention (PCI) of chronic total occlusion (CTO). Aim of this study is to assess the utility of minimum contrast media volume (CMV ≤ 50 mL) during CTO-PCI for CIN prevention in patients with chronic kidney disease (CKD). We extracted data from the Japanese CTO-PCI expert registry; 2863 patients with CKD who underwent CTO-PCI performed from 2014 to 2020 were divided into two groups: minimum CMV (n = 191) and non-minimum CMV groups (n = 2672). CIN was defined as an increased serum creatinine level of ≥ 25% and/or ≥ 0.5 mg/dL compared with baseline levels within 72 h of the procedure. In the minimum CMV group, the CIN incidence was lower than that in the non-minimum CMV group (1.0% vs. 4.1%; p = 0.03). Patient success rate was higher and complication rate was lower in the minimum CMV group than in the non-minimum CMV group (96.8% vs. 90.3%; p = 0.02 and 3.1% vs. 7.1%; p = 0.03). In the minimum CMV group, the primary retrograde approach was more frequent in the case of J-CTO = 1,2 and 3-5 groups compared to that in non-minimum CMV-PCI group (J-CTO = 0; 11% vs. 17.7%, p = 0.06; J-CTO = 1; 22% vs. 35.8%, p = 0.01; J-CTO = 2; 32.4% vs. 46.5%, p = 0.01; and J-CTO = 3-5; 44.7% vs. 80.0%, p = 0.02). Minimum CMV-PCI for CTO in CKD patients could reduce the incidence of CIN. The primary retrograde approach was observed to a greater extent in the minimum CMV group, especially in cases of difficult CTO.

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.

A Systematic Review and Meta-Analysis of Clinical Outcomes of Patients Undergoing Chronic Total Occlusion Percutaneous Coronary Intervention

OBJECTIVES

Chronic total occlusion (CTO) percutaneous coronary intervention (PCI) can improve patient symptoms, but it remains controversial whether it impacts subsequent clinical outcomes.

METHODS

In this systematic review and meta-analysis, we queried PubMed, ScienceDirect, Cochrane Library, Web of Science, and Embase databases (last search: September 15, 2021). We investigated the impact of CTO-PCI on clinical events including all-cause mortality, cardiovascular death, myocardial infarction (MI), major adverse cardiovascular event (MACE), stroke, subsequent coronary artery bypass surgery, target-vessel revascularization, and heart failure hospitalizations. Pooled analysis was performed using a random-effects model.

RESULTS

A total of 58 publications with 54,540 patients were included in this analysis, of which 33 were observational studies of successful vs failed CTO-PCI, 19 were observational studies of CTO-PCI vs no CTO-PCI, and 6 were randomized controlled trials (RCTs). In observational studies, but not RCTs, CTO-PCI was associated with better clinical outcomes. Odds ratios (ORs) and 95% confidence intervals (CIs) for all-cause mortality, MACE, and MI were 0.52 (95% CI, 0.42-0.64), 0.46 (95% CI, 0.37-0.58), 0.66 (95% CI, 0.50-0.86), respectively for successful vs failed CTO-PCI studies; 0.38 (95% CI, 0.31-0.45), 0.57 (95% CI, 0.42-0.78), 0.65 (95% CI, 0.42-0.99), respectively, for observational studies of CTO-PCI vs no CTO-PCI; 0.72 (95% CI, 0.39-1.32), 0.69 (95% CI, 0.38-1.25), and 1.04 (95% CI, 0.46-2.37), respectively for RCTs.

CONCLUSIONS

CTO-PCI is associated with better subsequent clinical outcomes in observational studies but not in RCTs. Appropriately powered RCTs are needed to conclusively determine the impact of CTO-PCI on clinical outcomes.

Impact of Timing and Treatment Strategy on Coronary Perforation During Percutaneous Coronary Intervention for Chronic Total Occlusion

Coronary perforations during chronic total occlusion percutaneous coronary intervention (CTO-PCI) are potential complications and reportedly associated with adverse events. This study aimed to describe the clinical characteristics and timing of perforations during CTO-PCI. Data from the Japanese CTO-PCI expert registry included 8,760 patients who underwent CTO-PCI between January 2014 and January 2019. The major adverse cardiac and cerebrovascular events were defined as death, tamponade, myocardial infarction, stent thrombosis, stroke, and revascularization. The guidewire manipulation time was defined as the time required to cross the CTO without perforation. Among these patients, 333 (3.8%) developed perforation during the CTO crossing attempt. Of the 333 patients, 29 developed cardiac tamponades (8.7%). Perforations more frequently occurred in a retrograde wiring than in an anterograde wiring (6.6% vs 1.7%, p <0.0001). A longer guidewire manipulation time was associated with the occurrence of perforation (median 101 minutes [interquartile range 59 to 150 minutes] in the perforation group vs 54.9 minutes [interquartile range 21.1 to 112.7 minutes] in the nonperforation group, p <0.0001). Risk factors for perforation were age, history of coronary bypass graft, right coronary artery lesion, de novo lesion, use of a stiff guidewire, and guidewire manipulation time of >60 minutes during anterograde wiring and age, non-left anterior descending artery lesion, use of a polymer-jacketed guidewire, and use of epicardial channel during retrograde wiring. In conclusion, risk factors for perforation were different between anterograde and retrograde wirings. A prolonged guidewire manipulation time was associated with the occurrence of perforation, especially during anterograde wiring.

Usefulness of the Transradial 8Fr Sheathless Guiding Catheter Approach in Directional Coronary Atherectomy

Background:

Directional coronary atherectomy (DCA) revived in Japan since 2014. DCA is a special device to remove the atherosclerotic plaque of coronary artery in percutaneous coronary intervention (PCI). However, DCA procedure is recommended to perform by 8Fr system, which is one of the limitations of DCA.

Case Series:

Since transradial approach is the main access route for PCI, we considered how to perform DCA by TRA. The external diameter of 8Fr guiding catheter (GC) and 6Fr sheath are 2.70 and 2.67 mm. Then, if 6Fr sheath can be inserted without any resistance, 8Fr GC is considered to be insertable. We performed 5 cases of DCA by the transradial 8Fr sheathless GC approach, all cases were successful without discomfort associated with insertion and removal of the 8Fr GC.

Conclusion:

DCA by the transradial 8Fr sheathless GC approach might be one of options to avoid bleeding complication and serve more comfortable treatment for the patients.

A Case Report: Directional coronary atherectomy supported with optical coherence tomography is useful for the slit lesion

Background: Directional coronary atherectomy (DCA) was revived in Japan in 2014. DCA is a special procedure to remove the atherosclerotic plaque of coronary artery during percutaneous coronary intervention. We present the case of a 91-year-old woman with symptoms of angina. Coronary angiography revealed significant stenosis with a slit lesion of the proximal left anterior descending artery. Because she had a high risk of bleeding, we did not want to implant a stent to prevent bleeding events. Then, we performed optical coherence tomography (OCT) and intravascular ultrasound to evaluate the morphology of the slit lesion in more detail. OCT showed clearly that the direction of the flap was counterclockwise and the edge of the flap was located in the epicardium. Since we could understand the localization of plaque distribution fully by OCT examination, we successfully removed the flap by DCA based on information from OCT. After that, we performed balloon dilatation with a 3.0-mm drug-coated balloon and finished without implanting the stent successfully. Her symptoms completely disappeared and postoperative course was good.

DCA supported with OCT might be one of the options in high bleeding risk patients, suggesting a potential stent-less therapeutic option.

<Learning objective: There may be hesitation about implantation of stents in patients with high risk of bleeding, such as the elderly. Stent-less percutaneous coronary intervention using directional coronary atherectomy followed by drug-coated balloon under optical coherence tomography (OCT) guidance may be the one of the option for patients with a high risk of bleeding, because OCT can more clearly show the feature of the lesion and the effect of treatment compared to intravascular ultrasound.>

Contemporary Issues in Chronic Total Occlusion Percutaneous Coronary Intervention

Remarkable progress has been achieved in chronic total occlusion (CTO) percutaneous coronary intervention (PCI) in recent years, with refinement of the indications and technical aspects of the procedure, imaging, and complication management. Randomized controlled trials and rigorous prospective registries have provided high-quality data on the benefits and risks of CTO PCI. Global collaboration has led to an agreement on nomenclature, indications, endpoint definition, and principles of clinical trial design that have been distilled in global consensus documents such as the CTO Academic Research Consortium. Increased use of preprocedural coronary computed tomography angiography and intraprocedural intravascular imaging, as well as development of novel techniques and structured CTO crossing and complication management algorithms, allow a systematic, stepwise approach to this difficult lesion subset. This state-of-the-art review provides a comprehensive discussion about the most recent developments in the indications, preprocedural planning, technical aspects, complication management, and future directions of CTO PCI.

The Effect of Aggressive Wire Recanalization in Calcified Atheroma and Dilatation (ARCADIA) Technique in Eccentric Calcified Lesion of No-stenting Zone

PURPOSE

The endovascular approach for eccentric calcified lesions of the no-stenting zone is challenging. This study aimed to investigate the effect of a novel technique for these lesions.

METHODS

We performed EVT for severe and eccentric calcified lesions using the technique, which is presented previously and named aggressive wire recanalization in calcified atheroma and dilatation (ARCADIA). In brief, a guidewire is passed to the residual lumen firstly. Next, another guidewire is advanced into and cross through the calcified plaque and returned to the distal original lumen with intravascular ultrasound (IVUS) guided. The calcified plaque is dilated by using a scoring-balloon or non-compliant balloon.

RESULTS

Consecutive 14 peripheral artery disease patients with isolated and eccentric calcification in a no-stenting zone were treated using ARCADIA technique between January 2018 and March 2020. In IVUS data, lumen cross-section area was significantly increased from 5.2 ± 2.0 mm² to 18.1 ± 6.9 mm² (p < 0.01), lumen area was expanded roundly evaluating as symmetry index from 0.45 ± 0.09 to 0.81 ± 0.12 (p < 0.01). There were no distal embolization and perforation after ARCADIA technique. One-year target lesion revascularization occurred in only 2 cases. The primary patency of 1 year was 85.7%.

CONCLUSION

ARCADIA technique is safe and appropriate, and can be 1 option to treat for eccentric calcified lesions of the no-stenting zone as an optimal wire crossing method.

Procedural characteristics and outcomes following chronic total occlusion coronary intervention: pooled analysis from 5 registries

BACKGROUND

Recent improvements in clinical skills, technology, and hardware have resulted in improved success rates with chronic total occlusion (CTO) percutaneous coronary intervention (PCI). We performed a study level pooled analysis from the five largest registries of percutaneous coronary intervention (PCI) of CTO.

RESEARCH DESIGN AND METHODS

We conducted pooled analysis of 9500 patients in registries and data on procedural characteristics, technical success, and MACCE was collected.

RESULTS

A total of 9500 patients were included in the analysis. Mean age was 65.4 years with previous CABG in 24.8%, reattempt procedure in 24.8% and mean JCTO score was 2.2. Final wiring strategy in hybrid algorithm-based registries was AWE in 40.8-58%, Retrograde in 24-35%, ADR in 16-25% and in Expert JCTO and EURO CTO was AWE in 72-75% and retrograde in 25-28%. Technical success was achieved in 87.8%. In hospital MACCE was 2.5% (95% CI: 1.8- 3.4%), mortality 0.44% (95% CI: 0.23-0.84%), stroke 0.2% (95% CI: 0.1-0.3%); myocardial infraction 1.6% (95% CI: 1.1-2.2%); and cardiac tamponade 0.8% (95% CI: 0.5 to 1.3%).

CONCLUSION

CTO PCI is currently performed with high technical success rates and low complication rates in experienced hands utilizing various techniques.

Outcomes of successful vs. failed contemporary chronic total occlusion percutaneous coronary intervention

BACKGROUND

There are limited contemporary data on the impact of success vs. failure on the outcomes of chronic total occlusion (CTO) percutaneous coronary intervention (PCI).

METHODS

We conducted a systematic review and a meta-analysis of contemporary studies that compared the outcomes in patients who underwent successful vs. failed contemporary (2010 onwards) CTO PCI. We performed a sensitivity analysis limited to studies that started enrollment after the publication of the hybrid algorithm in 2012.

RESULTS

We included five studies with a total of 6,084 patients (successful CTO PCI n = 4,861, failed CTO PCI n = 1,223). During a median follow-up time of 12 months (range 6-60 months), successful CTO PCI was associated with a lower risk of major adverse cardiovascular events [OR: 0.61, 95% CI (0.41, 0.92), p = 0.02, I² = 63%] and all-cause death [OR: 0.57, 95% CI (0.33, 0.99), p = 0.05, I² = 60%]. Both groups had similar risk of myocardial infarction (MI) [OR 0.69, 95% CI (0.43, 1.10), p = 0.38, I² = 80%], target vessel revascularization (TVR) [OR: 0.56, 95% CI (0.25, 1.27), p = 0.17, I² = 80%], and stroke [OR: 0.52, 95% CI (0.14, 1.91), p = 0.33, I² = 0%].

CONCLUSION

In contemporary practice, successful CTO PCI was associated with a lower incidence of MACE driven by lower all-cause mortality compared with failed CTO PCI at a median follow-up of 1 year.

Occlusion patterns, strategies and procedural outcomes of percutaneous coronary intervention for in-stent chronic total occlusion

BACKGROUND

In-stent chronic total occlusion (CTO) presents various occlusion patterns, which complicate percutaneous coronary intervention (PCI).

AIMS

The aim of the study was to investigate the initial outcome and strategy of PCI for in-stent CTO according to the angiographic occlusion patterns.

METHODS

This study assessed 791 in-stent CTOs from the Japanese CTO-PCI Expert Registry from 2015 to 2018. They were divided into four patterns: pattern A (n=419), CTO within the stent segment; pattern B (n=196), CTO beyond the distal edge; pattern C (n=85), CTO beyond the proximal edge; and pattern D (n=69) CTO beyond both the proximal and distal edges.

RESULTS

There were significant differences in the technical success rates (96.2%, 86.2%, 92.9%, and 75.4% for patterns A-D, respectively; p<0.001), guidewire crossing times (22 [interquartile range: 10-46], 52 [24-102], 40 [20-78], and 86 [45-127] min, respectively; p<0.001), and the rates of antegrade approach alone (90.9%, 61.2%, 67.1%, and 31.9%, respectively; p<0.001).

CONCLUSIONS

PCI for CTO within the stent segment was associated with excellent initial outcomes with the antegrade approach. However, PCI for CTO beyond both the proximal and distal edges was associated with the poorest outcomes, even with the bidirectional approach.

Global Chronic Total Occlusion Crossing Algorithm: JACC State-of-the-Art Review

The authors developed a global chronic total occlusion crossing algorithm following 10 steps: 1) dual angiography; 2) careful angiographic review focusing on proximal cap morphology, occlusion segment, distal vessel quality, and collateral circulation; 3) approaching proximal cap ambiguity using intravascular ultrasound, retrograde, and move-the-cap techniques; 4) approaching poor distal vessel quality using the retrograde approach and bifurcation at the distal cap by use of a dual-lumen catheter and intravascular ultrasound; 5) feasibility of retrograde crossing through grafts and septal and epicardial collateral vessels; 6) antegrade wiring strategies; 7) retrograde approach; 8) changing strategy when failing to achieve progress; 9) considering performing an investment procedure if crossing attempts fail; and 10) stopping when reaching high radiation or contrast dose or in case of long procedural time, occurrence of a serious complication, operator and patient fatigue, or lack of expertise or equipment. This algorithm can improve outcomes and expand discussion, research, and collaboration.

Predictors of prolonged guidewire manipulation time for native coronary chronic total occlusion percutaneous coronary intervention via primary antegrade approach

OBJECTIVES

This study aimed to identify the predictive factors for the guidewire manipulation time (GWMT) of ≥20 and 30 min for chronic total occlusion-percutaneous coronary intervention (CTO-PCI) via the primary antegrade approach (PAA).

BACKGROUND

Selection of primary retrograde approach (PRA) and the optimal timing to switch from antegrade to retrograde approach for coronary CTO-PCI is still debatable.

METHODS

Using the Japanese CTO-PCI expert registry data, we selected and analyzed 4461 patients who underwent CTO-PCI via PAA alone. The considerable lesion/anatomical factors for GWMT ≥20 and 30 min were analyzed. The risks of prolonged GWMT ≥20 and 30 min were stratified as easy, intermediate, difficult, and very difficult according to the multivariate analysis.

RESULTS

Nine lesion/anatomical characteristics (blunt stump, side branch at proximal cap, bifurcation at the exit point, calcification, tortuosity, occlusion length ≥ 20 mm, reattempt, nonleft anterior descending artery (nonleft anterior descending artery [LAD]), and tandem CTO) were independent predictors of GWMT ≥20 min (all p < 0.05). Excluding the nonLAD and tandem CTO, the same factors of GWMT ≥20 min correlated with GWMT ≥30 min (all p < 0.05). The distributions were increased in easy, intermediate, difficult, and very difficult subsets of GWMT ≥20 min (58.3%, 77.2%, 89.1%, and 100%) and GWMT ≥30 min (47.5%, 69.2%, 83.9%, and 100%).

CONCLUSIONS

These predictive factors of prolonged GWMT should be assessed before CTO-PCI via PAA and when considering an adequate timing to switch the retrograde or PRA if clinically available.

Japanese multicenter registry evaluating the antegrade dissection reentry with cardiac computerized tomography for chronic coronary total occlusion

Recently, antegrade dissection re-entry (ADR) with re-entry device for chronic total occlusion (CTO) percutaneous coronary intervention (PCI) has evolved to become one of the pillar techniques of the hybrid algorithm. Although the success rate of the device is high, it could be improved. We sought to evaluate the current trends and issues associated with ADR in Japan and evaluate the potential of cardiac computed tomography angiography (CCTA) for ADR procedure. A total 48 patients with CTO suitable for ADR evaluated by baseline conventional angiography and CCTA were enrolled. Procedural success and technical success were evaluated as the primary and secondary observations. Furthermore, all puncture points were analyzed by CCTA. CT score at each punctured site depended on the location of plaque deposition (none; + 0, at isolated myocardial site; + 1, at epicardial site; + 2) and the presence of calcification (none; + 0, presence; + 1) was analyzed and calculated (score 0–3). Overall procedure success rate was 95.8%. Thirty-two cases were attempted with the ADR procedure and 25 cases of them were successful. The technical success rate was 78.1% and myocardial infarction or other major complications were not observed in any cases. CT score at 60 puncture sites in 32 cases were analyzed and the score at technical success points was significantly smaller compared to that at technical failure points (0.68 ± 1.09 vs 1.77 ± 1.09, p < 0.0001). CTO-PCI with Stingray device in Japan could achieve a high procedure success and technical success rate. Pre procedure cardiac CT evaluation might support ADR procedure for appropriate patient selection or puncture site selection.

Definitions and Clinical Trial Design Principles for Coronary Artery Chronic Total Occlusion Therapies: CTO-ARC Consensus Recommendations

Over the past 2 decades, chronic total occlusion (CTO) percutaneous coronary intervention has developed into its own subspecialty of interventional cardiology. Dedicated terminology, techniques, devices, courses, and training programs have enabled progressive advancements. However, only a few randomized trials have been performed to evaluate the safety and efficacy of CTO percutaneous coronary intervention. Moreover, several published observational studies have shown conflicting data. Part of the paucity of clinical data stems from the fact that prior studies have been suboptimally designed and performed. The absence of standardized end points and the discrepancy in definitions also prevent consistency and uniform interpretability of reported results in CTO intervention. To standardize the field, we therefore assembled a broad consortium comprising academicians, practicing physicians, researchers, medical society representatives, and regulators (US Food and Drug Administration) to develop methods, end points, biomarkers, parameters, data, materials, processes, procedures, evaluations, tools, and techniques for CTO interventions. This article summarizes the effort and is organized into 3 sections: key elements and procedural definitions, end point definitions, and clinical trial design principles. The Chronic Total Occlusion Academic Research Consortium is a first step toward improved comparability and interpretability of study results, supplying an increasingly growing body of CTO percutaneous coronary intervention evidence.

Incidence and Predictive Factors of Chronic Vessel Enlargement After Percutaneous Coronary Intervention for Severely Stenotic and Occluded Lesions

BACKGROUND

Chronic vessel enlargement (CVE) of the coronary artery is observed in patients who undergo percutaneous coronary intervention (PCI) for severely stenotic or occluded lesions. Recently, the presence of a peri-medial high-echoic band (PHB) identified by intravascular ultrasound (IVUS) has been reported to correlate with this phenomenon. We sought to assess the incidence, predictive factors of CVE, and association between CVE and PHB.

METHODS

From January 2017 to December 2018, 97 patients, with 101 severely stenotic and occluded lesions, who underwent IVUS-guided PCI and a 9-month follow-up angiography were enrolled. CVE was defined as more than a 10% increase of distal lumen gain at follow-up angiography. All lesions were stratified into 2 groups: CVE group and non-CVE group. Clinical outcomes were compared and predictive factors for CVE were assessed. Relationships between PHB angle and CVE were also assessed.

RESULTS

At follow-up angiography, CVE was observed in 27 lesions (26.7%, 27/101). PHBs were frequently observed in the CVE group (88.9%), which was significantly higher than that in the non-CVE group (40.5%). The multivariate logistic regression analysis revealed that the presence of PHB was the only predictive factor for CVE (odds ratio, 11.3; 95% confidence interval, 2.95-43.0; p < 0.001). In addition, a linear relationship was observed between the incidence of CVE and PHB angle. The number of patients with CVE significantly increased in cases with a PHB angle more than 180 degrees.

CONCLUSIONS

The presence of PHB strongly predicts CVE after PCI for severely stenotic or occluded lesions.

A case of right coronary artery chronic total occlusion with difficulty in retrograde system establishment

Advances in microcatheters (MCs) enables the establishment of retrograde systems for the treatment of chronic total occlusion (CTO). However, there are still cases in which establishing a retrograde system is difficult because the guidewire or MC cannot pass through due to calcification, stenosis, or tortuosity. We present a case of a 56-year-old man with angina. Coronary angiography revealed a CTO of the right coronary artery (RCA). Although we started an antegrade approach at first, the guidewire went to subintimal lumen. We switched to a retrograde approach. Although the guidewire passed through posterolateral (PL) channel, the MC could not pass due to a stenosis at the junction of the main RCA trunk. Therefore, we negotiated the septal channel; however, it could only be guided in the peripheral direction. When the guidewire was more advanced in the peripheral direction, it crossed the guidewire that had previously passed through the PL channel. Then, when a balloon was delivered via the septal channel and trapped the guidewire from the PL channel, the MC was successfully delivered via the PL channel. After establishing the retrograde system, revascularization succeeded smoothly. In conclusion, this technique can be one option for the treatment of CTO patients. <Learning objective: Even if a guidewire passes retrogradely, the establishment of the retrograde system may be difficult in some cases since the microcatheter cannot pass retrogradely. This technique can be one of the effective options for the treatment of patients with chronic total occlusion when establishing a retrograde system is difficult.>.

Japanese multicenter registry evaluating the antegrade dissection reentry with cardiac computed tomography for chronic coronary total occlusion

Objective

This study was performed to evaluate the efficacy of cardiac computed tomography (CT) for antegrade dissection re-entry (ADR) technique in chronic total occlusion (CTO) percutaneous coronary intervention (PCI).

Background

Although PCI of CTO is a rapidly evolving field, procedure success rate remains suboptimal. Recently, ADR with Stingray device for CTO-PCI has also evolved to one of the pillar technique of the hybrid algorithm. Although the success rate of the device could be improved, it also remains not always high especially as first crossing strategy.

Methods

Forty eight patients with total occlusion suitable for revascularization evaluated by baseline coronary angiography and cardiac CT were enrolled in this study from April 2017 to April 2019 from 30 enrolled centers. The primary observation was procedural success. Furthermore, all puncture point with Stingray were analyzed by cardiac CT. In each point, 1) plaques on the isolated myocardial side at distal puncture site (+1 point), 2) any plaques excluded above definition at distal puncture site (+2 points), 3) calcification on both 1 and 2 at distal puncture site (+1 point) were analyzed and calculated the score (Score 0–3) (Figure 1).

Results

Overall procedure success rate was 95.8% (46/48) and antegrade success rate was 91.3% (42/46). Sixteen cases were succeeded with single guidewire escalation and 32 cases were attempted ADR with Stingray system. Within them, 25 cases were succeeded and 7 cases were observed puncture failure. And 3cases were succeeded with IVUS guide and 2 cases were with retrograde appTechnical success rate with stingray was 78.1% (25/32). Cardiac CT was analyzed 60 puncture sites in 32 cases which were attempted ADR with stingray system (1.88 sites/case). CT score at ADR success point was significantly smaller compare to that at ADR failure point (0.68±1.09 vs 1.77±1.09, p&lt;0.0001).

Conclusions

Pre procedure Cardiac CT and CT score might be useful for ADR technique in CTO PCI not only for case selection but also for puncture site selection.

Figure 1

Funding Acknowledgement

Type of funding source: None

Efficacy of plaque debulking for bifurcated or ostial lesions by directional coronary atherectomy prior to second-generation drug eluting stenting

OBJECTIVES

We sought to evaluate the efficacy of plaque debulking by directional coronary atherectomy (DCA) prior to second-generation drug-eluting stent (DES) implantation for bifurcated coronary lesions.

BACKGROUND

Percutaneous coronary intervention (PCI) for bifurcated lesions still remains complex and challenging in terms of restenosis or stent thrombosis regardless of whether simple or complex stenting is used.

METHODS

Patients with bifurcated lesions were enrolled in this prospective multicenter registry. Pre-second-generation DES plaque debulking with a novel DCA catheter (ATHEROCUT®, Nipro Co., Osaka, Japan) was conducted. All patients were scheduled to perform a follow up angiography (9-12 month coronary angiography or coronary computed tomography). The primary end point was target vessel failure (TVF) at follow up. Secondary end points were procedure-related events and major adverse cardiac events at 1 year.

RESULTS

A total of 77 patients with bifurcated lesions were enrolled. PCI with DCA was performed successfully in all cases without any major procedure-related event and only one case required complex stenting. The TVF rate at 9-12 month follow up was 3.9% (3 of 77) and those were all associated with revascularization of the target vessel. Restenosis was only observed at the ostium of the main-branch in three cases. No death, coronary artery bypass grafting, or myocardial infarction were reported for any patients within the first year.

CONCLUSION

DCA before second-generation DES implantation can possibly avoid complex stenting and provide a good mid-term outcome in patients with bifurcated lesions.

Efficacy of drug-coated balloon angioplasty after directional coronary atherectomy for coronary bifurcation lesions (DCA/DCB registry)

OBJECTIVES

To evaluate the efficacy and safety of additional drug-coated balloon (DCB) angioplasty after directional coronary atherectomy (DCA) for coronary bifurcation lesions.

BACKGROUND

The optimal therapy for bifurcation lesions has not been established, even in the drug-eluting stent era. DCA possibly prevents plaque and carina shift in bifurcation lesions by plaque debulking; however, the efficacy of combined DCA and DCB (DCA/DCB) for bifurcation lesions remains unclear.

METHODS

This multicenter registry retrospectively recruited patients with bifurcation lesions who underwent DCA/DCB and follow-up angiogram at 6-15 months. The primary endpoint was the 12-month target vessel failure (TVF) rate. The secondary endpoints were procedure-related major complications, major cardiovascular events at 12 months, restenosis at 12 months, target lesion revascularization (TLR) at 12 months, and target vessel revascularization (TVR) at 12 months.

RESULTS

We enrolled 129 patients from 16 Japanese centers. One hundred and four lesions (80.6%) were located around the left main trunk bifurcations. No side branch compromise was found intraoperatively. Restenosis was observed in three patients (2.3%) at 12 months. TLR occurred in four patients (3.1%): 3 (2.3%) in the main vessel and 1 (0.8%) in the ostium of the side branch at 12 months. TVF incidence at 12 months was slightly higher in 14 patients (10.9%), and only two patients (1.6%) had symptomatic TVR. One patient (0.8%) had non-target vessel-related myocardial infarction.

CONCLUSIONS

Our data suggested that DCA/DCB provided good clinical outcomes and minimal side branch damage and could be an optimal non-stent percutaneous coronary intervention strategy for bifurcation lesions.

Advances in CrossBoss/Stingray use in antegrade dissection reentry from the Asia Pacific Chronic Total Occlusion Club

Antegrade dissection reentry with Stingray device (Boston Scientific, Marlborough, MA) accounts for 20–34% of the chronic total occlusion (CTO) cases in the various hybrid operators' CTO registries and is an important component of CTO crossing algorithms. The Stingray device can facilitate antegrade dissection and reentry, however its use is low outside North America and Europe. The Asia Pacific CTO Club along with three experience Stingray operators from the US, Europe and India, created an algorithm guiding use of the CrossBoss and Stingray catheter. This APCTO Stingray algorithm defines when to use the CrossBoss and Stingray device recommending a reduction in CrossBoss use except for in‐stent restenosis lesions and immediate transition from knuckle wiring to the Stingray device. When antegrade wiring fails, choice of Stingray‐facilitated reentry versus parallel wiring depends on operator experience, device availability, cost concerns, and anatomical factors. When the antegrade wire enters the subintimal space, we recommend using a rotational microcatheter to produce a channel and deliver the Stingray balloon—so called the “bougie technique.” We recommend early switch to Stingray rather than persisting with single wire redirection or parallel wire. We recommend choosing a suitable reentry zone based on preprocedural computer tomography or angiogram, routine use of stick and swap, routine use of Subintimal TRAnscatheter Withdrawal (STRAW) through the Stingray balloon, and the multi stick and swap technique. We believe these techniques and algorithm can facilitate incorporation of the Stingray balloon into the practice of CTO interventionists globally.

Assessment of reattempted percutaneous coronary intervention strategy for chronic total occlusion after prior failed procedures: Analysis of the Japanese CTO-PCI Expert Registry

OBJECTIVES

We aimed to investigate strategies for reattempted percutaneous coronary interventions (PCIs) for chronic total occlusions (CTOs) by highly skilled operators after a failed attempt.

BACKGROUND

Development of complex techniques and algorithms has been standardized for CTO-PCI. However, there is no appropriate strategy for CTO-PCI after a failed procedure.

METHOD

From 2014 to 2016, the Japanese CTO-PCI Expert Registry included 4,053 consecutive CTO-PCIs (mean age: 66.8 ± 10.9 years; male: 85.6%; Japanese CTO [J-CTO] score: 1.92 ± 1.15). Initial outcomes and strategies for reattempted CTO-PCIs were evaluated and compared with first-attempt CTO-PCIs.

RESULTS

Reattempt CTO-PCIs were performed in 820 (20.2%) lesions. The mean J-CTO score of reattempt CTO-PCIs was higher than that of first-attempt CTO-PCIs (2.86 ± 1.03 vs. 1.68 ± 1.05, p < .001). The technical success rate of reattempt CTO-PCIs was lower than that of first-attempt CTO-PCIs (86.7% vs. 90.8%, p < .001). Regarding successful CTO-PCIs, the strategies comprised antegrade alone (reattempt: 36.1%, first attempt: 63.8%), bidirectional approach (reattempt: 54.4%, first attempt: 30.3%), and antegrade approach following a failed bidirectional approach (reattempt: 9.4%, first attempt: 5.4%). Parallel wire technique, intravascular ultrasound guide crossing, and bidirectional approach technique were frequently performed in reattempt CTO-PCIs. Reattempt CTO-PCIs showed higher rates of myocardial infarction (2.1% vs. 0.9%, p < .001) and coronary perforation (6.9% vs. 4.2%, p = .002) than first-attempt CTO-PCIs.

CONCLUSIONS

The technical success rate of reattempt CTO-PCIs is lower than that of first-attempt CTO-PCIs. However, using more complex strategies, the success rate of reattempt CTO-PCI can be improved by highly skilled operators.

P974Efficacy of plaque debulking for bifurcated or ostial lesion by directional coronary atherectomy before 2nd generation drug eluting stent (PERFECT2)

Objectives

We sought to evaluate the efficacy of plaque debulking by directional coronary atherectomy (DCA) before 2nd generation drug-eluting stent (DES) implantation for bifurcated coronary lesions.

Background

Percutaneous coronary intervention (PCI) for bifurcated lesions still remains complex and challenging in terms of restenosis or stent thrombosis regardless of whether simple or complex stenting used.

Methods

Patients with bifurcated lesions were enrolled in this prospective multicenter registry. Pre-2nd generation DES plaque debulking with a novel DCA was conducted. All patients were scheduled to perform a follow up (9–12 months) angiography (coronary angiography or coronary computed tomography). The primary end point was the target vessel failure (TVF) at follow-up. Secondary end points were procedure-related events and major adverse cardiac events at 1 year.

Results

A total of 77 patients with bifurcated lesions were enrolled. PCI with DCA was performed successfully in all without any major procedure-related event and only 1 case needed complex stenting. TVF rate at 9–12 months follow up was 3.9% (3 of 77) and those were all associated with revascularization of the target vessel. Restenosis was only observed at ostial of main-branch in 3cases. No death, no coronary artery bypass grafting, and no myocardial infarction were reported in the patients within the first year.

Figure1

Conclusion

DCA before 2nd generation DES implantation can possibly avoid complex stenting and provide a good mid-term outcome in patients with bifurcated lesions.

Acknowledgement/Funding

None

P5750Manipulation strategy for crossing coronary chronic total occlusion: an update from the Japanese CTO-PCI expert registry

Background

The percutaneous coronary intervention (PCI) strategy for chronic total occlusion (CTO) based on the guidewire manipulation time remains infrequent.

Purpose

We aimed to assess CTO-PCI strategy on the basis of guidewire manipulation time.

Methods

A total of 5843 patients undergoing CTO PCI between January 2014 and December 2017 and enrolled in the Japanese CTO-PCI expert registry were assessed. Their CTO-PCI strategies, procedural outcomes, and guidewire manipulation time were analysed.

Results

The primary retrograde approach was performed on 1562 patients (26.7%). The overall guidewire and technical success rates were 92.8% and 90.6%, respectively. Median guidewire manipulation time of guidewire success and failure were 56 (interquatile range [IQR]: 22 to 111) min and 176 (IQR: 130 to 229) min, respectively. The average Japanese CTO score of the primary antegrade approach with the antegrade alone, the primary antegrade approach with the retrograde approach, and the primary retrograde approach were 1.7±1.1, 2.1±1.2, and 2.3±1.1, respectively (p<0.001). Median successful guidewire crossing time of single wiring in the antegrade alone was 23 (IQR: 11 to 44) min, and that of the primary retrograde approach was significantly shorter than that of the primary antegrade approach with the retrograde approach (107 [IQR: 70 to 161] min vs. 126 [IQR: 87 to 174] min; p<0.001). Reattempt, CTO length ≥20 mm, and proximal cap ambiguity were the predictors of guidewire failure in the primary antegrade approach with antegrade alone, but were not those in the primary retrograde approach.

Conclusions

Although successful guidewire crossing time of the primary antegrade approach with the antegrade alone is short, that of the primary retrograde approach can be shorter than that of the primary antegrade approach with the retrograde approach. Choosing an appropriate CTO-PCI strategy leads to shortening of successful guidewire crossing time.

124Impact of intimal tracking for recanalization of CTO lesions on long-term clinical outcomes

Background

For recanalization of coronary chronic total occlusion (CTO) lesions, subintimal guidewire tracking in both antegrade and retrograde approaches are commonly used.

Purpose

This study aimed to assess the impact of subintimal tracking on long-term clinical outcomes after recanalization of CTO lesions.

Methods

Between January 2009 and December 2016, 474 CTO lesions (434patients) were successfully recanalized in our center. After guidewire crossing in a CTO lesion, those lesions were divided into intimal tracking group (84.6%, n=401) and subintimal tracking group (15.4%, n=73) according to intravascular ultrasound (IVUS) findings. Long-term clinical outcomes including death, target lesion revascularization (TLR), target vessel revascularization (TVR) were compared between the two groups. In addition, the rate of re-occlusion after successful revascularization was also evaluated.

Results

The median follow-up period was 4.7 years (interquartile range, 2.8–6.1). There was no significant difference of the rate of cardiac death between the two groups (intimal tracking vs. subintimal tracking: 7.0% vs. 4.1%; hazard ratio, 0.61; 95% confidence interval [CI], 0.19 to 2.00; p=0.41), TLR (14.3% vs. 16.2%; hazard ratio, 1.34; 95% CI, 0.71 to 2.53; p=0.37), and TVR (17.5% vs. 20.3%; hazard ratio, 1.27; 95% CI, 0.72 to 2.23; p=0.42). However, the rate of re-occlusion was significantly higher in the subintimal tracking group than intimal tracking group at 3-years re-occlusion (4.2% vs. 14.5%; log-rank test, p=0.002, Figure). In the multivariate COX regression, subintimal guidewire tracking was an independent predictor of re-occlusion after CTO recanalization (HR: 5.40; 95% CI: 2.11–13.80; p<0.001).

Figure 1

Conclusions

Subintimal guidewire tracking for recanalization of coronary CTO was associated with significantly higher incidence of target lesion re-occlusion during long-term follow-up period.

Guiding Principles for Chronic Total Occlusion Percutaneous Coronary Intervention

Outcomes of chronic total occlusion (CTO) percutaneous coronary intervention (PCI) have improved because of advancements in equipment and techniques. With global collaboration and knowledge sharing, we have identified 7 common principles that are widely accepted as best practices for CTO-PCI.  1. Ischemic symptom improvement is the primary indication for CTO-PCI.  2. Dual coronary angiography and in-depth and structured review of the angiogram (and, if available, coronary computed tomography angiography) are key for planning and safely performing CTO-PCI.  3. Use of a microcatheter is essential for optimal guidewire manipulation and exchanges.  4. Antegrade wiring, antegrade dissection and reentry, and the retrograde approach are all complementary and necessary crossing strategies. Antegrade wiring is the most common initial technique, whereas retrograde and antegrade dissection and reentry are often required for more complex CTOs.  5. If the initially selected crossing strategy fails, efficient change to an alternative crossing technique increases the likelihood of eventual PCI success, shortens procedure time, and lowers radiation and contrast use.  6. Specific CTO-PCI expertise and volume and the availability of specialized equipment will increase the likelihood of crossing success and facilitate prevention and management of complications, such as perforation.  7. Meticulous attention to lesion preparation and stenting technique, often requiring intracoronary imaging, is required to ensure optimum stent expansion and minimize the risk of short- and long-term adverse events. These principles have been widely adopted by experienced CTO-PCI operators and centers currently achieving high success and acceptable complication rates. Outcomes are less optimal at less experienced centers, highlighting the need for broader adoption of the aforementioned 7 guiding principles along with the development of additional simple and safe CTO crossing and revascularization strategies through ongoing research, education, and training.

Overview and proposed terminology for the reverse controlled antegrade and retrograde tracking (reverse CART) techniques

During recent years, equipment and techniques for percutaneous coronary intervention (PCI) of chronic total occlusions (CTO) have improved significantly. The retrograde approach remains critical to the improved success of CTO PCI. Currently, the reverse controlled antegrade and retrograde tracking (CART) technique has become the dominant retrograde wire crossing technique. In this article, we propose a standardised terminology and classification for this technique divided into three subtypes: a) conventional reverse CART, usually involving the use of large balloons on the antegrade wire to achieve re-entry within the CTO segment; b) "directed" reverse CART, which is characterised by small antegrade balloon size and more active, intentional vessel tracking and penetration with a controllable retrograde wire, still within the CTO segment; and c) "extended" reverse CART, in which the intimal/subintimal dissection is extended proximal or distal to the CTO segment, achieving re-entry outside the CTO segment. The proposed standardised terminology will facilitate the communication, teaching and adoption of the reverse CART techniques.

Chronic Total Occlusion Wiring: A State-of-the-Art Guide From The Asia Pacific Chronic Total Occlusion Club

OBJECTIVE

Despite the advances in wire technology and development of algorithm-driven methodology for chronic total occlusion (CTO) intervention, there is a void in the literature about the technical aspects of CTO wiring. The Asia Pacific CTO Club, a group of 10 experienced operators in the Asia Pacific region, has tried to fill this void with this state-of-the-art review on CTO wiring.

METHODS

This review explains, for proximal cap puncture: choices of wires, shaping of the wire, use of dual lumen catheter, and method of step-down of wire penetration force for successful wiring. In wiring the CTO body, the techniques of loose tissue tracking, intentional intimal plaque tracking, and intentional subintimal wiring are described in detail. For distal lumen wiring, a blunt distal cap, presence of a distal cap side branch, calcium, and sharp tapered distal stump predict cap toughness, and wire penetration force should be stepped-up in these cases. The importance of choosing between redirection, parallel wiring, and Stingray (Boston Scientific, Marlborough, MA, USA) for angiographic guidance is discussed along with which will be more successful. On the retrograde side, the problems encountered with distal cap puncture and methods to overcome these problems are explained. The method of wiring the CTO body through a retrograde approach depending on the morphology of the CTO is described. Different reverse controlled antegrade and retrograde tracking (CART) wiring methods - including end balloon wiring, side balloon entry, and conventional reverse CART - are explained in detail.

CONCLUSION

This is a systematic CTO wiring review, which is believed to be beneficial for CTO operators worldwide.

Retrograde algorithm for chronic total occlusion from the Asia Pacific Chronic Total Occlusion club

Retrograde CTO PCI is an effective method to improve the success rate of CTO PCI. Despite several comprehensive and detailed descriptive papers on the retrograde techniques, retrograde CTO PCI remains difficult for many interventionists. We, the Asia Pacific CTO club, propose a new retrograde CTO PCI algorithm, which focuses on three specific problems in the retrograde approach. First, how to overcome the tough proximal cap. Then, how to cross the collateral channels safely and efficiently. Finally, how to cross the CTO and, in particular, the problems of reverse CART. We explain our new philosophy of contemporary reverse CART. We hope that this algorithm will provide the tools for operators to overcome the difficulties of retrograde CTO PCI and that it will become a platform for discussion, training, and proctoring for the retrograde approach.

A New Algorithm for Crossing Chronic Total Occlusions From the Asia Pacific Chronic Total Occlusion Club

Although the hybrid chronic total occlusion (CTO) algorithm had many excellent recommendations, there has been infrequent adoption in the Asia Pacific region. The Asia Pacific CTO club propose an algorithm for case selection based on the Japan-CTO score and a new CTO algorithm, which is applicable globally. This algorithm allows for differing skill sets and equipment availability and contains practical teaching for CTO percutaneous coronary intervention. Similar to the hybrid algorithm there are 3 main questions that determine whether the primary approach is antegrade or retrograde: 1) is there proximal cap ambiguity; 2) is the distal vessel of poor quality; and 3) are there interventional collaterals present. In contrast to the hybrid algorithm occlusion length alone does not determine the choice of either a wire escalation strategy or a dissection re-entry strategy. Rather a combination of factors including ambiguity of the vessel course, severe calcification, tortuosity, length, and previous failure are used to determine this. The role of intravascular ultrasound-guided entry to overcome proximal cap ambiguity and the CrossBoss catheter in occlusive in-stent restenosis are highlighted in the algorithm. Both the parallel wire technique and dissection re-entry with the Stingray system have been included as options when the initial antegrade wire passage fails. Intravascular ultrasound-guided wiring along with limited subintimal tracking and re-entry are included as final options in the algorithm. Finally, the algorithm incorporates guidance on when to stop the procedure. It is hoped that this algorithm will serve as the basis for future CTO percutaneous coronary intervention proctoring and training.

In vivo tissue characterization of human atherosclerotic plaques by optical coherence tomography: A directional coronary atherectomy study with histopathologic confirmation

BACKGROUND

The histopathological validation of optical coherence tomography (OCT) in visualizing atherosclerotic plaques has been reported only in ex vivo studies. We sought to evaluate the accuracy of OCT in tissue characterization in vivo.

METHODS AND RESULTS

A total of 25 patients with stable angina pectoris who underwent directional coronary atherectomy (DCA) were included in the investigation, whereby OCT was performed before and after a single debulking. The debulked region was determined on OCT and classified into fibrous tissue, lipid, calcification, thrombus, and macrophage accumulation, which were compared with histology. Changes in OCT signal intensity in the deeper intimal region after DCA were also visually evaluated. Fibrous tissues were detected in all cases, while thrombus was identified only in 1 case, by both OCT and histology. The sensitivity, specificity, positive and negative predictive values, and predictive accuracy for lipid detection by OCT were 88.9%, 75.0%, 66.7%, 92.3%, and 80.0%; those for calcification were 50.0%, 100%, 100%, 91.3%, and 92.0%; and those for macrophage accumulation were 85.7%, 88.9%, 75.0%, 94.1%, and 88.0%, respectively. The false positive diagnoses for lipid were mostly attributed to the extracellular matrix accumulation containing less collagen. The false negative diagnoses for calcification were explained by the presence of lipid around the calcification. The OCT signal intensity in the deeper intimal region substantially increased after DCA in all cases.

CONCLUSIONS

The current study showed excellent predictive accuracy of in vivo OCT in tissue characterization, whereas the limitations of OCT were highlighted by an over-detection of lipid, under-detection of calcification, and underestimation of the deeper intimal matrix.

Novel proctorship effectively teaches interventionists coronary artery chronic total occlusion lesions

BACKGROUND

Interventionists' experience and skills are essential factors for successful chronic total occlusion-percutaneous coronary intervention (CTO-PCI). However, the construction of theoretical strategy independent from interventionists' procedure may also improve it. We sought to assess the feasibility of CTO-PCI using an educational system supported by a single expert proctor.

METHODS

A total of 160 patients underwent CTO-PCI between 2009 and 2016 at 92 Japanese centers in the Hands-on proctorship project. The CTO-PCI strategy was discussed with all participants and their specialists, before and during the procedure. We divided patients into 2 groups based on the CTO-PCI experience of their interventionist: (1) the less experienced group (CTO-PCI ≤50 cases, n=65) and (2) the more experienced group (CTO-PCI >50 cases, n=95). Baseline characteristics, procedural complications, and clinical outcomes were compared between groups.

RESULTS

No significant differences in patient age, sex, prevalence for coronary risk factors, and lesion complexity was observed between groups. The retrograde approach was used equivalently between groups (55.4% vs. 60.0%, p=0.56), and procedural success rates were similar (96.9% vs. 90.5%, p=0.12). The rate of proctor's bailout for recanalization were not frequent between groups (4.6% vs. 5.3%, p=0.85). No procedure-related mortality was noted in either group. In addition, no significant differences in procedural cardiac complications, including coronary dissection, perforation, or tamponade, were observed between groups (10.8% vs. 14.7%, p=0.47).

CONCLUSIONS

The expert-supported CTO-PCI maintained high success rates regardless of interventionists' experience. This highlights the importance of theoretical strategy for the management patients undergoing CTO-PCI.