Retrograde Percutaneous Recanalization of Chronic Total Occlusion of the Coronary Arteries

Transradial retrograde percutaneous coronary intervention of chronic total occlusion using a single guiding catheter: a case report

BACKGROUND

With the development of specialized equipment and the retrograde technique, success rates for percutaneous coronary intervention of chronic total occlusions have increased from 60 to 90% in the past 10 years. Performing percutaneous coronary intervention via a collateral channel from the contralateral artery, using two guiding catheters, is usually the preferred approach to retrograde chronic total occlusion-percutaneous coronary intervention. In the case described in this report, we performed successful retrograde revascularization of chronic total occlusion of dominant left circumflex artery via the ipsilateral septal collateral artery from the left anterior descending artery. The procedure was performed successfully through radial artery access using a single guiding catheter. An 85-year-old white Bulgarian Caucasian male patient, with a history of lateral and inferior myocardial infarction 20 years ago and previous percutaneous coronary intervention, underwent a planned coronary arteriography owing to his complaints of typical angina symptoms. Coronary angiography revealed three-vessel coronary artery disease with patent implanted drug-eluting stents in the mid-left anterior descending artery and in the proximal right coronary artery and chronic total occlusion of dominant left circumflex artery. A septal branch in the midsegment of left anterior descending artery was supplying the distal left circumflex artery retrogradely. After repeated failed attempts at antegrade percutaneous coronary intervention for the left circumflex artery's chronic total occlusion, the retrograde approach was tried. This intervention finally succeeded through the ipsilateral septal collateral. It was performed via a single radial artery access throughout the whole process. Postoperatively, the patient had no complications and was stable at the 6-month follow-up.

CONCLUSION

The transradial approach to retrograde percutaneous coronary intervention for chronic total occlusions via an ipsilateral septal collateral using a single guiding catheter is feasible and safe in appropriately selected cases.

Antegrade approach versus retrograde approach percutaneous coronary intervention for chronic total occlusion: An updated meta-analysis

BACKGROUND

Retrograde approach has notably improved success rates of chronic total occlusion (CTO) percutaneous coronary intervention (PCI). However, longer procedural time, increase use of fluoroscopy and contrast dye have been reported in retrograde techniques in CTO PCI. We aimed to study in-hospital and long-term outcomes of retrograde approach versus antegrade approach in CTO PCI.

METHODS

We searched PubMed, Scopus, WOS, and Cochrane Central until June 2023 to include all relevant studies that compared retrograde approach versus antegrade approach in patients with CTO PCI. We synthesized the outcome data using a random-effects model, expressing the effect estimates as odds ratios (OR) or mean difference (MD) with corresponding 95 % confidence intervals (CI).

RESULTS

A total of 18 studies comprising 21,276 patients were included in the analysis. Regarding in-hospital outcomes, antegrade approach was associated with lower odds of MACE (OR= 0.34, 95 % CI: 0.23 to 0.51), all-cause mortality (OR= 0.35, 95 % CI: 0.19 to 0.64), MI (OR= 0.36, 95 % CI: 0.25 to 0.53), urgent pericardiocentesis (OR= 0.27, 95 % CI: 0.16 to 0.46), CIN (OR= 0.46, 95 % CI: 0.33 to 0.65), procedural complications (OR= 0.52, 95 % CI: 0.33 to 0.83), target vessel perforation (OR= 0.45, 95 % CI: 0.32 to 0.64). while antegrade was associated with higher success rates (OR= 1.16, 95 % CI: 1.1 to 1.22).

CONCLUSION

Compared to antegrade technique, retrograde was associated with higher risk for in-hospital and long-term adverse events, and preferably should be performed in more complex CTO lesions.

Unlocking Success: Strategies for Preventing and Managing Complications in Chronic Total Occlusion Percutaneous Coronary Intervention Procedures

Complications in percutaneous coronary intervention (PCI), particularly in chronic total occlusion (CTO) cases, pose notable challenges, with a mortality rate of approximately 0.4% during hospitalization, mainly due to issues like perforation and tamponade. Although risk assessment tools can aid in evaluating periprocedural complication risk, prevention and preparedness take precedence. Guided by the "3 Ps" framework-prevention, preparedness, and planning-we navigate the complexities of managing complications in CTO PCI procedures. This emphasizes the importance of comprehensive patient discussions, adherence to appropriateness use criteria, and ensuring a well-trained team equipped with standardized equipment. Furthermore, it is crucial to extract valuable insights from encountered complications, turning potential setbacks into invaluable learning opportunities. This positive approach not only fosters individual growth but also contributes to the advancement of CTO PCI practices. Various complications specific to CTO PCI are addressed, including donor vessel injury, equipment loss/entrapment, radiation injury, and coronary perforation.

Dissection and Re-entry Techniques for Chronic Total Occlusion Percutaneous Coronary Intervention

Despite early stagnation in success rates for percutaneous coronary intervention for chronic total occlusion with the traditional antegrade wiring approach, the introduction of dissection/re-entry techniques and the retrograde approach opened new avenues for operators to tackle more complex occlusions. Dissection/re-entry techniques (both antegrade and retrograde) are commonly used in angiographic scenarios characterised by long, tortuous and calcified occlusions, as well as in those with proximal cap ambiguity. Familiarity and comfort using the extraplaque space (with either an antegrade or retrograde approach) have become fundamental to achieving safe and effective recanalisation of complex chronic total occlusions. This review provides an overview of different contemporary antegrade and retrograde dissection re-entry techniques and their acute and longer-term outcomes.

Intravascular Imaging-Guided Versus Coronary Angiography-Guided Complex PCI: A Meta-analysis of Randomized Controlled Trials

INTRODUCTION

Trials evaluating the role of intravascular imaging in percutaneous coronary intervention (PCI) for complex coronary artery disease have yielded mixed results. This study aimed to compare the outcomes of intravascular imaging specifically intravascular ultrasound (IVUS) with those from conventional coronary angiography in complex PCI.

METHODS

Comprehensive electronic search of MEDLINE, EMBASE, and Cochrane databases was performed until March 2023 for randomized clinical trials (RCTs) comparing intravascular imaging with coronary angiography in patients undergoing complex PCI. Complex PCI was defined per each study, and included PCI for American College of Cardiology/American Heart Association (ACC/AHA) type B2/C lesions, unprotected left main coronary artery disease, or multivessel stenting. The primary study outcome was major adverse clinical events (MACE).

RESULTS

The meta-analysis included 10 RCTs with a total of 6615 patients (3576 in the intravascular imaging group and 3039 in the coronary angiography group). The weighted mean-follow up was 28.9 months. Compared with coronary angiography, intravascular imaging reduced MACE (8% vs. 13.3%; relative risk [RR] 0.63; 95% confidence interval [CI] 0.54-0.73), cardiac death (RR 0.47; 95% CI 0.31-0.73), definite/probable stent thrombosis (RR 0.48; 95% CI 0.24-0.97), target vessel revascularization (RR 0.62; 95% CI 0.46-0.83), and target lesion revascularization (RR 0.61; 95% CI 0.47-0.79). There was no difference between both groups in all-cause death (RR 0.79; 95% CI 0.53-1.18) and myocardial infarction (RR 0.80; 95% CI 0.61-1.04).

CONCLUSION

In patients undergoing complex PCI, intravascular imaging-specifically IVUS-reduced MACE by decreasing the incidence of cardiac death, stent thrombosis, and target vessel and target lesion revascularization.

Controlled antegrade and retrograde subintimal tracking (CART) for recanalisation of chronic total occlusions

BACKGROUND

Controlled antegrade and retrograde subintimal tracking (CART) is rarely performed in contemporary chronic total occlusion (CTO) percutaneous coronary intervention (PCI).

AIMS

We aimed to analyse the indications, procedural characteristics, and outcomes of CART at a high-volume CTO programme.

METHODS

We included all patients undergoing a retrograde CTO PCI in which CART was performed at our institution between January 2019 and November 2023. The primary endpoint was technical success.

RESULTS

Of 1,582 CTO PCI, the retrograde approach was performed in 603 procedures (38.1%), and CART was used in 45 cases (7.5%). The mean age was 69.1±10.3 years, 93.3% were male, and prior coronary artery bypass graft surgery was present in 68.9%. The most common target CTO vessel was the right coronary artery (48.9%). Anatomical complexity was high (Multicentre CTO Registry of Japan [J-CTO] score of 3.6±0.9). The most common collateral used for CART was a saphenous vein graft (62.2%). Advanced calcium modification was required in 15.6% of cases. CART was successful in 73.3%. Technical and procedural success was 82.2%. Coronary perforation was diagnosed in 4 subjects (8.9%), but only 1 patient (2.2%) suffered tamponade and required pericardiocentesis. No other in-hospital major adverse cardiac events were diagnosed.

CONCLUSIONS

CART is a useful technique in selected, very complex CTOs tackled with the retrograde approach. Success rates were high, while complication rates were low, considering the high anatomical complexity and baseline patient risk.

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.

Collateral grading systems in retrograde percutaneous coronary intervention of chronic total occlusions

BACKGROUND

The Japanese Channel (J-Channel) score was introduced to aid in retrograde percutaneous coronary intervention (PCI) of chronic total coronary occlusions (CTOs). The predictive value of the J-Channel score has not been compared with established collateral grading systems such as the Rentrop classification and Werner grade.

AIMS

To investigate the predictive value of the J-Channel score, Rentrop classification and Werner grade for successful collateral channel (CC) guidewire crossing and technical CTO PCI success.

METHODS

A total of 600 prospectively recruited patients underwent CTO PCI. All grading systems were assessed under dual catheter injection. CC guidewire crossing was considered successful if the guidewire reached the distal segment of the CTO vessel through a retrograde approach. Technical CTO PCI success was defined as thrombolysis in myocardial infarction flow grade 3 and residual stenosis <30%.

RESULTS

Of 600 patients, 257 (43%) underwent CTO PCI through a retrograde approach. Successful CC guidewire crossing was achieved in 208 (81%) patients. The predictive value of the J-Channel score for CC guidewire crossing (area under curve 0.743) was comparable with the Rentrop classification (0.699, p = 0.094) and superior to the Werner grade (0.663, p = 0.002). Technical CTO PCI success was reported in 232 (90%) patients. The Rentrop classification exhibited a numerically higher discriminatory ability (0.676) compared to the J-Channel score (0.664) and Werner grade (0.589).

CONCLUSIONS

The J-channel score might aid in strategic collateral channel selection during retrograde CTO PCI. However, the J-Channel score, Rentrop classification, and Werner grade have limited value in predicting technical CTO PCI success.

Incidence, Predictors, and Strategies for Retrograde Wire Tracking Failure via Poor Septal Collateral Channels in Chronic Total Occlusion

Background

Retrograde guidewire (GW) tracking success via a poor septal collateral channel (CC) when an antegrade approach fails is crucial for successful revascularization of coronary chronic total occlusion (CTO) with poor septal CC. However, the incidence, predictors, and management strategies for retrograde GW tracking failure via poor septal CC remain unclear.

Methods

In total, 122 CTO patients who underwent retrograde septal percutaneous coronary intervention (PCI) with poor CC between January 2017 and May 2022 were retrospectively analyzed. Patients were divided into the retrograde GW tracking success group (success group) and the retrograde GW tracking failure group (failure group). Clinical and angiographic data were compared to investigate the predictors of retrograde GW tracking failure.

Results

The incidence of GW tracking failure was 22.1% (27/122). Patients in the failure group had a higher prevalence of left anterior descending artery (LAD) CTO (66.7% vs 37.9%; p = 0.009) and a higher incidence of well-developed non-septal collateral (66.7% vs 30.5%; p = 0.001). Patients with a septal CC diameter ≥ 1 mm (48.1% vs 70.5%; p = 0.040), ≥ 3 septal CCs (44.4% vs 66.3%; p = 0.046), and initial retrograde application of Guidezilla (37.0% vs 60.0%; p = 0.048) were significantly lower in the failure group than in the success group. The binary logistics regression model showed that a CC diameter < 1 mm, well-developed non-septal collateral, and LAD CTO were independent predictors for GW tracking failure in patients undergoing retrograde CTO PCI via poor septal CC.

Conclusion

The success rate of retrograde GW tracking via poor septal CC was high, with a relatively high procedural success rate. A CC diameter < 1 mm, well-developed non-septal collateral, and LAD CTO were independent predictors of GW tracking failure in patients undergoing retrograde CTO PCI via poor septal CC.

A Chinese scoring system for predicting successful retrograde collateral traverse in patients with chronic total coronary occlusion

BACKGROUND

Retrograde approach technique has been challenging in percutaneous coronary interventional treatment of chronic total occlusion (CTO) coronary disease. The present study endeavors to determine a novel Chinese scoring system for predicting successful collateral channels traverse via retrograde approach.

METHODS

The demographic characteristics and angiographic characteristics of 309 CTO patient were analyzed by univariable and multivariable analysis for selecting potential predictors. And the nomogram was used to establish the scoring system. Then it was evaluated by the internal and external validation.

RESULTS

The predictors of Age, Connections between collateral channels and recipient vessels, and Channel Tortuosity (ACT) were identified with univariable and multivariable analysis and employed to the ACT score system. With acceptable calibrations, the area under curve of the scoring system and the external validation were 0.826 and 0.816 respectively. Based on score, the predictors were divided into three risk categories and it showed a consistent prediction power in the validation cohort.

CONCLUSIONS

The novel Chinese ACT score is a reliable tool for predicting successful retrograde collateral traverse.

Retrograde Approach via Ipsilateral Septal Collateral Channel in Percutaneous Coronary Intervention for Coronary Chronic Total Occlusion: A Single-Center Experience

Background

The septal collateral channel (CC) is the preferred channel in retrograde percutaneous coronary intervention (PCI) for chronic total occlusion (CTO). However, reports on the utilization of the ipsilateral septal CC are limited.

Objective

To evaluate the feasibility and safety of the ipsilateral septal CC in retrograde CTO PCI.

Methods

Twenty-five patients with successful wire CC tracking via the ipsilateral septal CC in retrograde CTO PCI were retrospectively analyzed. All procedures were performed by experienced CTO operators. Procedures were divided into the left descending coronary artery (LAD)-septal-LAD group and the LAD-septal-left circumflex coronary artery (LCX) group. Procedural complications and in-hospital outcomes were ascertained.

Results

Both groups were similar with respect to risk factors and angiographic characteristics of the CTO, except for the collateral tortuosity (86.7% vs 20%, p=0.002). The success rate of microcatheter CC tracking was 96%. Both technical success and procedural success rates were 92%. Procedural complications were found in one case (septal perforation, 4%), which happened in the LAD-septal-LAD group (p=0.250). One postoperative adverse event (Q-wave myocardial infarction, 4%) was observed before discharge.

Conclusion

The retrograde approach via the ipsilateral septal CC was feasible, with high success rates and acceptable complications, in the hands of experienced operators.

Forewarned Is Forearmed: Machine Learning Algorithms for the Prediction of Catheter-Induced Coronary and Aortic Injuries

Catheter-induced dissections (CID) of coronary arteries and/or the aorta are among the most dangerous complications of percutaneous coronary procedures, yet the data on their risk factors are anecdotal. Logistic regression and five more advanced machine learning techniques were applied to determine the most significant predictors of dissection. Model performance comparison and feature importance ranking were evaluated. We identified 124 cases of CID in electronic databases containing 84,223 records of diagnostic and interventional coronary procedures from the years 2000-2022. Based on the f1-score, Extreme Gradient Boosting (XGBoost) was found to have the optimal balance between positive predictive value (precision) and sensitivity (recall). As by the XGBoost, the strongest predictors were the use of a guiding catheter (angioplasty), small/stenotic ostium, radial access, hypertension, acute myocardial infarction, prior angioplasty, female gender, chronic renal failure, atypical coronary origin, and chronic obstructive pulmonary disease. Risk prediction can be bolstered with machine learning algorithms and provide valuable clinical decision support. Based on the proposed model, a profile of 'a perfect dissection candidate' can be defined. In patients with 'a clustering' of dissection predictors, a less aggressive catheter and/or modification of the access site should be considered.

Operator experience and clinical outcomes of percutaneous coronary intervention for chronic total occlusion: insights from a pooled analysis of the Japanese CTO PCI Expert Registry and the Retrograde Summit General Registry

There have not been enough studies to examine the association between difference in operator experience and technical success rate in contemporary percutaneous coronary intervention for chronic total occlusion (CTO-PCI). The present study sought to provide insights into the impact of operator experience on clinical outcomes of CTO-PCI through a comparison of two largest Japanese CTO-PCI registries consisting of operators with different CTO-PCI experience. After combining clinical data from the Japanese CTO-PCI Expert Registry (ER) 2014-2016 (N = 4316) including CTO-PCI performed by highly experienced operators and the Retrograde Summit General Registry (RSGR) 2014-2016 (N = 2230) including CTO-PCI performed by less experienced operators, a pooled analysis was performed to compare clinical outcomes of CTO-PCI in 2 registries. The overall technical success rate and the incidence of in-hospital major adverse events were comparable between ER and RSGR (90.1% vs 88.9%, p = 0.133, 1.7% vs 1.5%, p = 0.606, respectively). Technical success rate in ER was significantly higher among the patients treated with primary antegrade approach (91.8% vs 89.5%, p = 0.009), whereas there was no significant difference among the patients treated with the primary retrograde approach (85.7% vs 85.3%, p = 0.857). Multivariate analysis suggested ER operator could not be an independent predictor for technical success. CTO-PCI performed by less experienced but appropriately trained operators could achieve similarly high technical success rate with comparable safety compared with those performed by highly experienced specialists in contemporary Japanese context.

One 6-F Guiding Catheter and One Microcatheter to Accomplish a Retrograde Chronic Total Occlusion Approach: The “Reverse Tip-In” or “Introspect” Technique

The retrograde approach has significantly increased the overall success rate of chronic total occlusion (CTO) percutaneous coronary intervention (PCI), up to 90% in the hands of experienced CTO operators. The “tip-in” technique involves inserting an antegrade microcatheter over the retrograde guidewire, allowing for antegrade intervention on the CTO segment. Through the presentation of the following case, we want to illustrate how to undertake a retrograde approach to bridge the occluded segment via the “reverse tip-in” or “introspect” technique, using a single guiding catheter with one microcatheter inside.

Retrograde Chronic Total Occlusion Percutaneous Coronary Interventions: Predictors of Procedural Success From the ERCTO Registry

OBJECTIVES

The aim of this study was to identify independent predictors of procedural success after retrograde chronic total occlusion (CTO) percutaneous coronary intervention (PCI).

BACKGROUND

Retrograde CTO PCI is an established technique, but predictors of success remain poorly understood.

METHODS

A multivariable logistic regression model was used to analyze potentially important demographic, clinical, anatomical, and technical aspects of retrograde CTO PCI cases uploaded to the multicenter European CTO (ERCTO) Club Registry.

RESULTS

In calendar years 2018 and 2019, 2,364 retrograde CTO PCI cases constituted the primary analysis cohort. A primary retrograde strategy was used in 1,953 cases (82.6%), and an initial antegrade approach was converted to retrograde in 411 cases (17.4%). Procedural success was achieved in 1,820 cases (77.0%) and was more likely to occur after a primary retrograde attempt versus conversion from an initial antegrade approach (80.9% vs 58.4%; P < 0.0001). After multivariable analysis, an absence of lesion calcification (OR: 1.86; 95% CI: 1.37-2.51; P < 0.0001), a higher degree of distal vessel opacification (OR: 2.47; 95% CI: 1.72-3.55; P < 0.0001), little or no proximal target vessel tortuosity (OR: 1.84; 95% CI: 1.28-2.64; P = 0.001), Werner collateral connection CC1 (OR: 4.87; 95% CI: 2.90-8.19; P < 0.0001) or CC2 (OR: 5.33; 95% CI: 3.02-9.42; P < 0.0001), and the top tertile of operator volume (>120 cases over 2 years) (OR: 1.88; 95% CI: 1.26-2.79; P = 0.002) were associated with the greatest chance of achieving angiographic success.

CONCLUSIONS

Less calcification with good distal vessel opacification, little or absent proximal vessel tortuosity, and visible collateral connections, along with high-volume operator status, were all independently predictive of angiographically successful retrograde CTO PCI.

Transradial Retrograde Percutaneous Coronary Intervention of Chronic Total Occlusion via an Ipsilateral Septal Collateral Using a Single Guiding Catheter: A Case Report

Background

With the development of specialized equipment and the retrograde technique, success rates for percutaneous coronary intervention (PCI) of chronic total occlusions (CTOs) have increased from 60 to 90% in the past 10 years. Performing PCI via a collateral channel from the contralateral artery, using two guiding catheters, is usually the preferred approach to retrograde CTO-PCI. In the case described in this report, only the ipsilateral septal collateral artery from the proximal occluded left anterior descending (LAD) artery was available. The procedure can be performed successfully from radial artery access using a single guiding catheter.

Case Summary

A 57-year-old patient, with a history of anterior and inferior myocardial infarction and previous PCI, underwent a planned coronary arteriography due to his complaints of typical angina symptoms. Coronary angiography revealed stent occlusion located mid-LAD and severe in-stent restenosis in the distal right coronary artery (RCA). A proximal septal branch was supplying the distal LAD retrogradely. After repeated failed attempts at antegrade PCI for the LAD's CTO, the retrograde approach was tried. This intervention finally succeeded through the ipsilateral septal collateral. It was performed via a single radial-artery access throughout the whole process. Post-operatively, the patient had no complications and was stable at 1-year follow-up.

Conclusion

The transradial approach to retrograde PCI for CTO via an ipsilateral septal collateral using a single guiding catheter is feasible and safe in appropriately selected cases.

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.

Overview of Contemporary Chronic Total Occlusion Percutaneous Coronary Intervention Techniques: A Narrative Systematic Review

BACKGROUND

Despite the abundance of coronary chronic total occlusions (CTO) percutaneous coronary intervention (PCI) studies, the literature is not easy to digest for both general PCI operators and CTO PCI specialists because of the many varied terms used for approaches and inconsistency in terminology. This inconsistency makes it challenging to understand the advantages and disadvantages of these different approaches and, most importantly, their downstream clinical outcomes. Accordingly, we conducted a systematic review of all published studies on CTO PCI to describe techniques and algorithms used in the last decade to provide an overview on the efficacy and safety of contemporary CTO PCI techniques.

METHODS

We performed a comprehensive search of the PubMed, EMBASE, and the Cochrane library databases for manuscripts about PCI of CTOs. We included studies published between the years 2005 and 2019. We categorized studies into those using a single approach (antegrade, retrograde) and those with a prespecified algorithm (ie, hybrid approach).

RESULTS

Fifty-five observational studies including 28,907 patients who underwent CTO were included in this review. CTO PCI generally carries low risk of major procedural complications, with angiographic success rates being higher in studies that used an algorithmic vs single technical approach.

CONCLUSIONS

This systematic review highlights the wide variation in definitions and practices in CTO PCI and calls for standardization in terminology and practice.

Simplified Dual-Lumen Catheter-Facilitated Reverse Wire Technique for Markedly Angulated Collateral Channel Entry in Retrograde Chronic Total Occlusion Intervention

The retrograde approach has significantly improved the success rates in complex coronary total occlusion (CTO) lesions. It has also become the predominant and important strategy in CTO recanalization. However, unsuccessful crossing of the collateral channels is the strongest predictor of retrograde failure, and adverse collateral channel morphology, including large channel entry angle, could reduce the success rate of collateral channel crossing. Reverse wire technique (RWT) was specifically developed for bifurcation lesions with an extremely angulated side branch, and nowadays, this can be achieved by the support of a dual-lumen catheter (DLC). We report a novel method named "simplified dual-lumen catheter-facilitated RWT" to facilitate markedly angulated collateral channel entry in retrograde CTO intervention. This new technique is simplified by making the reverse bend with the support of a DLC in the aorta instead of outside the guiding catheter, which is feasible, effective, and safe for markedly angulated collateral channel entry in retrograde CTO percutaneous coronary intervention (PCI).

Safety of Percutaneous Coronary Intervention for Chronic Total Occlusion in Patients With Multi-Vesel Disease: Sub-Analysis of the Japanese Retrograde Summit Registry

BACKGROUND

The success rate of percutaneous coronary intervention (PCI) for chronic total occlusion (CTO) has gradually increased thanks to the continuous development of devices and techniques. However, the impact of multi-vessel disease (MVD) on its success rate and safety is not well known.

METHODS

The clinical records of 5009 patients enrolled in the Japanese Retrograde Summit Registry and who had undergone PCI for CTO at 65 centers between 2012 and 2015 were reviewed. We compared the outcome for patients with and without MVD.

RESULTS

Two thousand nine hundred and seventy-eight patients (59%) had MVD. Although there was no significant difference in the J-CTO score between the two groups [MVD group 1.51 ± 1.07 vs. SVD group 1.48 ± 1.07, p = 0.48], the procedural success rate of CTO-PCI in the MVD group was significantly lower than that in the SVD group (87.2% vs. 90.2%, p = 0.001). However, occurrence of procedure-related adverse events (4% vs. 5%, p = 0.11), total fluoroscopy (70 ± 45 min vs. 69 ± 50 min, p = 0.75) and procedural time (154 ± 86 min vs. 151 ± 89 min, p = 0.36), and total amount of contrast media (219 ± 102 mL vs. 222 ± 105 mL, p = 0.33) did not differ between the two groups.

CONCLUSIONS

Although MVD had an impact on the success rate of CTO-PCI, it did not affect procedure-related adverse events.

Incidence, Predictors, and Strategies for Failure of Retrograde Microcatheter Tracking After Successful Wiring of Septal Collateral Channels in Chronic Total Occlusions

Background

Retrograde microcatheter collateral channel (CC) tracking after successful wiring of septal CC is crucial for retrograde revascularization of coronary chronic total occlusion (CTO). However, the incidence, predictors, and strategies for failure of retrograde microcatheter CC tracking after successful wiring of septal CC remain unclear.

Methods

In total, 298 patients with CTO who underwent retrograde septal CC PCI between January 2015 and May 2019 were retrospectively analyzed. Clinical data were compared to investigate the predictors of initial microcatheter tracking failure.

Results

The initial and final microcatheter tracking success rates were 79.2% (236/298) and 96.6% (288/298), respectively. The procedural success rate was 94.0% (280/298). The right coronary artery-to-left anterior descending artery septal ratio (48.4% vs 33.1%, p=0.037) and CC tortuosity (34.6% vs 20.8%, p=0.045) were significantly higher in the initial microcatheter CC tracking failure group than in the successful tracking group. Multivariate logistic regression analysis revealed that severe collateral tortuosity (odds ratio [OR]: 13.241, 95% confidence interval [CI]: 3.429–27.057, p=0.038), CC entry angle of <90° (OR:4.921, 95% CI: 1.128–9.997, p=0.002), CC exit angle of <90° (OR:5.037, 95% CI: 2.237–11.182, p=0.004), use of Finecross MG as initial microcatheter (OR:1.826, 95% CI: 1.127–3.067, p=0.035), and shunning initial retrograde application of Guidezilla (OR:0.321, 95% CI: 0.267–0.915, p=0.024) were variables independently associated with initial microcatheter CC tracking failure in patients with CTO undergoing retrograde septal CC PCI.

Conclusion

The overall initial microcatheter CC tracking failure was 20.8%. Severecollateral tortuosity, CC entry, and exit angle of <90°, use of Finecross MG as initial microcatheter, and shunning initial retrograde application of Guidezilla were variables independently associated with initial microcatheter CC tracking failure in patients with CTO undergoing retrograde septal PCI.

The hybrid algorithm in treatment of coronary chronic total occlusions - MSWiA Lublin CTO 5-year registry

INTRODUCTION

Treatment of chronic total occlusions (CTO) despite improvement in techniques and results over the last years still seems to be limited to a small number of centres and operators. Application of the hybrid strategy may support further spread of CTO percutaneous coronary intervention (PCI) and increase procedural success rates.

AIM

Our single-centre prospective ongoing registry aims to provide details and results of recanalizations of coronary CTO performed according to the hybrid algorithm in a series of consecutive patients.

MATERIAL AND METHODS

Between January 2015 and September 2019 the clinical and procedural data of CTO PCI procedures on consecutive patients were collected. Lesion complexity was assessed according to the Multicenter CTO Registry of Japan (J-CTO) score: 0 - easy, 1 - intermediate, 2 - difficult, ≥ 3 - very difficult and PROGRESS score. Strategies applied were classified as: antegrade wire escalation (AWE), antegrade dissection and re-entry (ADR), retrograde wire escalation (RWE) and retrograde dissection and re-entry (RDR). Angiographic success was defined as < 30% residual stenosis with TIMI 3 flow. Angiographic and clinical complications were reported.

RESULTS

Two hundred sixty-six patients were included and 285 procedures were performed in total. Success rate was 87.7% (calculated per procedure) and 92.5% (calculated per patient). Four patients underwent successful staged double CTO recanalization. Fifteen patients out of 31 primary failures underwent a second attempt with a 73% success rate (11/15). Fifty-two patients (18.2%) were referred for a second attempt from other institutions. Mean J-CTO score was 2.6 (13 cases with J-CTO of 0, 41 cases with J-CTO of 1, 80 cases with J-CTO of 2, and 151 cases with J-CTO ≥ 3) and the success rate was respectively 92.3%, 95.1%, 91.3% and 83.4%. Higher complexity of occlusion required a higher number of applied strategies including retrograde access in over a quarter of cases. Complete revascularization was achieved in 215 (75.4%) cases. In-hospital MACCE rate was 3.5% - 1 patient died due to acute kidney injury complications, 9 (3.2%) patients sustained myocardial infarction (1 STEMI due to side branch occlusion). All 7 (2.5%) coronary perforations (Ellis 1 and Ellis 2) were treated conservatively and we recognised 10 (3.5%) cases of acute kidney injury (one dialysis).

CONCLUSIONS

The hybrid algorithm in CTO PCI can be successfully applied with good early results and low complication rates. Higher complexity CTOs require more procedural strategies with a significantly lower success rate in very difficult cases.

Active Retrograde Extra Backup with a Mother-and-Child Catheter to Facilitate Retrograde Microcatheter Collateral Channel Tracking in Recanalization of Coronary Chronic Total Occlusion

OBJECTIVE

To explore the feasibility and safety of the active retrograde backup (ARB) for treatment of chronic total occlusion (CTO) during retrograde percutaneous coronary intervention (PCI).

BACKGROUND

Guiding support plays an important role in guidewire and microcatheter coronary channel (CC) tracking in retrograde PCI therapy for patients with CTO. However, the feasibility and safety of retrograde active use of a mother-and-child catheter are still unclear. Patients and Methods. A total of 271 consecutive patients with CTO who underwent retrograde PCI between January 2015 and January 2020 were retrospectively analyzed. Clinical data of two groups were compared to evaluate the feasibility and safety of ARB.

RESULTS

Of the 271 patients, 69.0% (187/271) underwent therapy through the septal branch, 31.0% (84/271) through the epicardial collateral channel, and 47.6% (129/271) through active retrograde extra backup with a mother-and-child catheter to facilitate retrograde microcatheter collateral CC tracking. The time of wire CC tracking was shorter in the ARB group than that in the non-ARB group (25.4 ± 8.5 vs 26.4 ± 9.7, p=0.348), but there was no significant difference. The duration of the retrograde microcatheter tracking (10.2 ± 3.8 vs 15.5 ± 6.8, p=0.012) and the retrograde approach (62.8 ± 20.3 vs 70.4 ± 24.3, p=0.026) in the ARB group was significantly shorter than that in the non-ARB group. The radiation dose (223.6 ± 112.7 vs. 295.2 ± 129.3, p=0.028), fluoroscopy time (50.6 ± 21.3 vs 62.3 ± 32.1, p=0.030), and contrast volume (301.8 ± 146.7 vs 352.2 ± 179.5, p=0.032) in the ARB group were significantly lower than that in the non-ARB group. There were no life-threatening procedural complications in either group. Complications unrelated to ARB included two cases of donor-vessel dissection, one case of CC perforation, and two cases of target-vessel perforation. There was no statistically significant difference in major adverse cardiac and cerebrovascular events between the groups during hospitalization (p > 0.05).

CONCLUSION

ARB is feasible, safe, and conducive to guidewire and microcatheter CC tracking in the recanalization of coronary CTO. It improves procedural efficiency and is worthy of further promotion.

Equipment utilization in chronic total occlusion percutaneous coronary interventions: Insights from the PROGRESS-CTO registry

BACKGROUND

We examined guidewire and microcatheter utilization during chronic total occlusion (CTO) percutaneous coronary intervention (PCI).

METHODS

We examined device utilization in 2,968 CTO PCIs performed in 2,936 patients at 19 US and two international center between January 2016 and January 2019.

RESULTS

The median number of antegrade guidewires used per case declined (5 in 2016 vs 3 in 2019) and was higher in higher complexity lesions (2 in J-CTO 0 vs. 8 in J-CTO 4 or 5 score). In antegrade-only procedures, the most frequently used guidewires were the Pilot 200 (Abbott Vascular, 37%), Fielder XT (Asahi Intecc, 25%) and Gaia third (Asahi Intecc, 18%), while the most commonly used microcatheters were the Turnpike Spiral (Vascular Solutions, 18%) and Turnpike (Vascular Solutions, 16%). Compared with 2012-2015, during 2016-2019 use of novel equipment such as the Gaia guidewires and the Turnpike microcatheters led to decreased use of Confianza Pro 12 (Asahi Intecc) wire and Corsair (Asahi Intecc) family of microcatheters. In retrograde cases, the guidewires most commonly used were the Sion (44%), Pilot 200 (27%) and Fielder FC (26%), while the Corsair/Corsair Pro, Turnpike LP (Vascular Solutions) and Caravel (Asahi Intecc) were the most frequently used microcatheters for collateral crossing (29%, 26% and 22%, respectively).

CONCLUSIONS

The most commonly used guidewires during CTO PCI are polymer-jacketed guidewires and the most commonly used microcatheters are torquable microcatheters.

Collateral Channel Size and Tortuosity Predict Retrograde Percutaneous Coronary Intervention Success for Chronic Total Occlusion

BACKGROUND

There is little evidence on how to select an interventional collateral channel (CC) in retrograde chronic total occlusion (CTO) percutaneous coronary intervention. We aimed to identify independent angiographic predictors of CC tracking and technical success in retrograde CTO percutaneous coronary intervention.

METHODS AND RESULTS

From January 2012 to December 2015, a total of 216 consecutive retrograde CTO percutaneous coronary intervention attempts by a high-volume operator in a tertiary university-affiliated hospital were enrolled. The clinical, angiographic, and procedural details were collected. The characteristics analyzed included channel type, size, tortuosity, angle of attack, length to emerging point, and the Multicenter CTO Registry of Japan score. The Multicenter CTO Registry of Japan score was 4.2±0.8. A total of 242 CCs were attempted for intervention. CC tracking success rate was 83.5%, and the technical success rate (per CC) was 81.4%. The per-patient technical success rate was 91.2%, and the major procedural complication rate was 4.6%. The atrioventricular groove, epicardial, and septal CCs were used in 36 (14.9%), 84 (34.7%), and 122 (50.4%) tracking attempts, respectively. In multivariable analysis, only large channel size and lack of tortuosity were significant independent predictors of CC tracking and technical success. A new scoring system was developed, while large size was given 1 point and lack of tortuosity was given 2 points. The receiver-operating characteristic area by the new model to predict CC tracking and technical success were 0.800 and 0.752, respectively.

CONCLUSIONS

In retrograde CTO percutaneous coronary intervention, only size and tortuosity of a CC are independent angiographic predictors of CC tracking and technical success.

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.

Microcatheter collateral channel tracking failure in retrograde percutaneous coronary intervention for chronic total occlusion: incidence, predictors, and management

AIMS

This study sought to demonstrate the incidence, predictors, and management of microcatheter collateral channel (CC) tracking failure in retrograde percutaneous coronary intervention (PCI) for chronic total occlusion (CTO) lesions.

METHODS AND RESULTS

Prospectively collected data from 371 consecutive retrograde CTO-PCI procedures between March 2015 and January 2018 were retrospectively analysed. The incidence of initial microcatheter CC tracking failure was 22.5% in 280 procedures with wire CC tracking success. For septal collaterals, CC grade 0-1 collaterals (odds ratio [OR]: 8.3; p<0.001), channel entry angle <90° (OR: 13.0; p=0.001), channel exit angle <90° (OR: 44.3; p=0.004), and Finecross MG as initial microcatheter (OR: 2.7; p=0.032) were independently related to initial microcatheter CC tracking failure. Meanwhile, the only predictor for epicardial collaterals was CC 1 collaterals (OR: 26.9; p<0.001). Frequently applied solutions included microcatheter switching (61.9%), and microcatheter switching combined with GUIDEZILLA (14.3%) or anchoring balloon technique (6.3%).

CONCLUSIONS

Initial microcatheter CC tracking failure was found in nearly one quarter of procedures after wire CC tracking success. Independent angiographic predictors of initial microcatheter CC tracking failure included CC 0-1 collaterals, channel entry angle <90°, and channel exit angle <90° for septal collaterals, and CC 1 collaterals for epicardial collaterals.

Recanalization of Chronic Total Occlusions Using Modern Endovascular Techniques

PURPOSE

to assess results of percutaneous coronary intervention (PCI) with contemporary endovascular techniques of recanalization of chronic total coronary artery occlusions (CTO) in patients with ischemic heart disease (IHD). Occlusion (CTO) he procedural and in-hospital outcomes of consecutive patients undergoing chronic total occlusion percutaneous coronary intervention.

MATERIALS AND METHODS

We retrospectively analyzed data from 456 consecutive patients (mean age 59.9±7.1 years, 18.2 % women) who underwent CTO PCI procedures (n=477) during 2014-2016 in the E. N. Meshalkin National Medical Research Center. CTO was localized in the right (61.2 %), left anterior descending (23.2 %) and left circumflex (15.3 %) coronary arteries. In one patient CTO was located in the left main coronary artery. According to the J-CTO score, 30 % of lesions were classified as easy, 36.4 % intermediate, 23.7 % difficult, and 18.9 % very difficult.

RESULTS

Technical and procedural successes were achieved in 374 (78.4 %) and 366 patients (76.7 %), respectively. Antegrade approach was used in 378 (79.2 %), retrograde approach - in 99 (20.7 %) cases. Retrograde approach as primary strategy was used in 27 cases (5.7 %). Most frequent access for CTO PCI was radial artery, contralateral injection was used in 151 cases (31.6 %). Total number of stents per lesion was 1.6±0.98. The mean fluoroscopy time was 36.2±31 min.

CONCLUSIONS

The rate of procedural adverse events in our study was low and similar to the non-CTO PCI series. However, despite the large number of CTO PCIs, the procedural success rate was still lower than in centers with dedicated programs for the management of such patients. Thus, further work is required to overcome this difference. Possible solution of this problem might be development and introduction in clinical practice of an algorithm for CTO recanalization.

Predictors, treatment, and long-term outcomes of coronary perforation during retrograde percutaneous coronary intervention via epicardial collaterals for recanalization of chronic coronary total occlusion

OBJECTIVE

To investigate predictors, treatment, and long-term outcomes associated with coronary perforation (CP) in patients who underwent retrograde percutaneous coronary intervention (PCI) through epicardial collaterals for chronic total occlusion (CTO).

BACKGROUND

Data regarding CP during retrograde PCI through epicardial collaterals for CTO are scarce.

METHODS

We included 155 patients who underwent retrograde CTO PCI through epicardial collaterals at Guangdong Cardiovascular Institute from August 2011 to December 2017. The median follow-up was 2.5 years. Major adverse cardiac events (MACEs) were analyzed using the Kaplan-Meier method, and independent predictors of long-term MACE were determined using a multivariable Cox model.

RESULTS

CP occurred in 24 (15.5%) patients, with the frequency of Ellis classes 1 or 2 and 3 being 41.7% and 58.3%, respectively. Seven (4.5%) patients had tamponade, which was effectively managed using coil embolization and pericardiocentesis. Renal dysfunction (odds ratio [OR]: 5.27; 95% confidence interval [CI]: 1.47-18.88; P = 0.011), right coronary artery (RCA) CTO (OR: 4.34; 95% CI: 1.29-14.63; P = 0.018), and Epi-CTO score ≥ 2 (OR: 3.27; 95% CI: 1.12-9.58; P = 0.030) were independent predictors of CP. At the 7-year follow-up, 17 patients had MACE. Multivariable analysis revealed that CP was not associated with worse long-term clinical outcomes (hazard ratio: 1.55; 95% CI: 0.45-5.32, P = 0.484).

CONCLUSIONS

Retrograde CTO PCI through epicardial collaterals is at increased risk of CP, which is associated with renal dysfunction, RCA CTO, and Epi-CTO score ≥ 2. Prompt and proper management of CP is important. CP is not significantly associated with adverse clinical outcomes.

Contemporary Approach to Chronic Total Occlusion Interventions

PURPOSE OF REVIEW

Chronic total occlusion (CTO) poses one of the greatest technical challenges to interventional cardiologists. Despite recent advancements in techniques and clinical trials showing significant benefits of CTO percutaneous coronary interventions (PCI), the proportion of patients with untreated CTOs remains high. We therefore aim to perform a comprehensive review of the various techniques available, recent advancements, benefits, and complications associated with CTO PCI.

RECENT FINDINGS

Three randomized clinical trials examining the benefits of CTO PCI have recently been presented. Scoring systems have been developed to facilitate pre-procedural estimation of success and complications of CTO PCI. Technological enhancements in coronary wires and other interventional equipment along with dedicated training for CTO operators have improved the likelihood of successful recanalization of CTOs. CTO PCI has been shown to improve patient symptoms and quality of life. It is therefore important to have an in-depth knowledge of the various CTO techniques, appropriate equipment, and complications when performing these complex procedures. Clinicians should weigh the risks and benefits and choose the appropriate patient population who may benefit from revascularization.

The Wire Rendezvous and Chasing Wire Technique in the Bidirectional Approach for the Percutaneous Coronary Intervention for Chronic Total Occlusion with a Single Guiding Catheter

A bidirectional approach for percutaneous coronary intervention for chronic total occlusion (CTO-PCI) using ipsilateral collaterals with a single guiding catheter limits procedural choices. The CTO of the left circumflex artery with ipsilateral collateral artery was treated by the bidirectional approach using a single guiding catheter. While the retrograde wire directly crossed the CTO lesion, the microcatheter could not pass the CTO lesion despite the conventional strategies. Therefore, we performed the wire rendezvous and chasing wire techniques. The wire rendezvous technique enables deeper retrograde guidewire progression, and the antegrade microcatheter can reach the CTO entry. The chasing wire technique enables the antegrade guidewire to pass the route made by the retrograde guidewire. These techniques might offer a possible solution for bidirectional CTO-PCI using a single guiding catheter. However, this technique should be considered as a last resort because of the risk of rapid reocclusion.

A step-by-step guide to mastering retrograde coronary chronic total occlusion intervention in 2018: The author's perspective

Chronic total occlusion remains one of the most challenging subsets and represents the "last frontier" of percutaneous coronary intervention. Retrograde recanalization is one of the most significant amendments of the technique and has become an important complement to the classical antegrade approach. It yields a high success rate even in most complex patients. With emergence of important iterations, this approach has become safer, faster, and more successful. The author proposes a step-by-step guide to the retrograde approach with alternatives to various steps for operators wishing to embark on this strategy.

Imaging during percutaneous coronary intervention for optimizing outcomes

Angiography is the current gold standard for imaging during percutaneous coronary interventions but has significant limitations. Catheter-based intravascular imaging techniques such as intravascular ultrasound and the more recent optical coherence tomography have the potential to overcome these limitations and thus optimize clinical outcomes. In this update, we discussed the current applications of the available imaging techniques, existing evidence, continuing unmet needs, and potential areas for further research.

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.

Diagnostic accuracy of multi-slice computed tomography in identifying lesion characteristics in coronary total occlusion

We performed this study to compare the sensitivity and specificity of multi-slice computed tomography (MSCT) to coronary angiography (CA) in detecting coronary total occlusion (CTO) lesion characteristics. Moreover, we analyzed the association between these characteristics and the risk of revascularization failure. Fifty patients with confirmed CTO diagnosis were tried for revascularization using the antegrade (all 50) or retrograde (in failed nine antegrade interventions) approaches. Each patient underwent CA and MSCT before the intervention and data from both modalities were compared using the SPSS software. Successful revascularization occurred in 36 (72%) and 6 (66.7%) patients of the antegrade and retrograde groups, respectively. Compared to CA, MSCT exhibited high sensitivity in detecting CTO segment calcification (100%), size of the affected vessel (100%, area under the curve [AUC] = 0.82), distal filling of the affected segment (97.7%) and side-branching at the CTO segment (93.3%). However, it had lower sensitivity in detecting collaterals (75%) and the length of the affected segment (87.5%, AUC = 0.77). According to MSCT data, increased occlusion length > 18 mm (p = 0.01), atherosclerotic vessel wall (p = 0.02), small distal vessel size ≤ 2.75 mm (p = 0.002), proximal side-branching (p = 0.01) and calcification of the proximal cap (p = 0.007) or distal stump (p = 0.01) were associated with an increased risk of revascularization failure. MSCT exhibited high sensitivity in identifying several CTO lesion characteristics, such as lesional calcification and size of the affected vessel. However, further research is needed to improve the diagnostic accuracy of this modality and define the predictors of revascularization failure in CTO patients.

The Hybrid Approach to Chronic Total Occlusion Percutaneous Coronary Intervention: Update From the PROGRESS CTO Registry

OBJECTIVES

The aim of this study was to determine the techniques and outcomes of hybrid chronic total occlusion (CTO) percutaneous coronary intervention (PCI) in a diverse group of patients and operators on 2 continents.

BACKGROUND

CTO PCI has been evolving with constant improvement of equipment and techniques.

METHODS

Contemporary outcomes of CTO PCI were examined by analyzing the clinical, angiographic, and procedural characteristics of 3,122 CTO interventions performed in 3,055 patients at 20 centers in the United States, Europe, and Russia.

RESULTS

The mean age was 65 ± 10 years, and 85% of the patients were men, with high prevalence of diabetes (43%), prior myocardial infarction (46%), prior coronary artery bypass graft surgery (33%), and prior PCI (65%). The CTO target vessels were the right coronary artery (55%), left anterior descending coronary artery (24%), and left circumflex coronary artery (20%). The mean J-CTO (Multicenter Chronic Total Occlusion Registry of Japan) and PROGRESS CTO (Prospective Global Registry for the Study of Chronic Total Occlusion Intervention) scores were 2.4 ± 1.3 and 1.3 ± 1.0, respectively. The overall technical and procedural success rate was 87% and 85%, respectively, and the rate of in-hospital major complications was 3.0%. The final successful crossing strategy was antegrade wire escalation in 52.0%, retrograde in 27.1%, and antegrade dissection re-entry in 20.9%; >1 crossing strategy was required in 40.9%. Median contrast volume, air kerma radiation dose, and procedure and fluoroscopy time were 270 ml (interquartile range: 200 to 360 ml), 2.9 Gy (interquartile range: 1.7 to 4.7 Gy), 123 min (interquartile range: 81 to 188 min) and 47 min (interquartile range: 29 to 77 min), respectively.

CONCLUSIONS

CTO PCI is currently being performed with high success and acceptable complication rates among various experienced centers in the United States, Europe, and Russia. (Prospective Global Registry for the Study of Chronic Total Occlusion Intervention [PROGRESS CTO]; NCT02061436).

Epicardial collateral channel for retrograded recanalization of chronic total occlusion percutaneous coronary intervention: Predictors of failure and procedural outcome

OBJECTIVES

This study set out to identify significant lesion features of chronic total occlusion (CTO) that predict successful retrograde recanalization via epicardial collateral channels (CCs).

BACKGROUND

Epicardial CCs remain essential in retrograde percutaneous coronary intervention (PCI) of CTO. However, the unpredictability of success and occurrence of complications limit the application of epicardial CCs for retrograde PCI technique for CTO.

METHODS

103 retro-recanalization cases were analyzed using epicardial CCs with successful recanalization as an end point. Clinical and angiography data were collected.

RESULTS

The total success rate was 76.3%. Independent predictors associated with technical success included CCs tortuosity, side branch at CCs tortuosity, inadequate CCs Size and inadequate CCs exit location. Assigning a score of one for each variable, four levels of difficulty were obtained and formed the EPI-CTO score (Epicardial CTO). This score had significant predictive value for the likelihood of successful recanalization (AUC: 0.94, 95%CI: 0.89-0.98). Coronary and CCs perforation occurred in 6 and 10 cases respectively. Four cases including two coronary and two CCs perforations had tamponade that needed pericardiocentesis.

CONCLUSIONS

Using epicardial CCs for retrograde approach of CTO PCI is effective. Complication rate was acceptable. We found four independent predictors relative to procedure success.

Predictors of poor clinical outcomes after successful chronic total occlusion intervention with drug-eluting stents

BACKGROUND

The aim of this study was to identify the prognostic predictors for the worse clinical outcomes after a successful chronic total occlusion (CTO) intervention with drug-eluting stents.

PATIENTS AND RESULTS

A total of 2334 patients in the multicenter Korean CTO registry who underwent a successful CTO intervention with drug-eluting stents (first generation, 1367, new generation, 967) were enrolled. The primary endpoint was the composite of cardiac death, myocardial infarction, and stent thrombosis.The cumulative incidence of the primary endpoint was 2.5% (median follow-up duration: 22 months). In multivariate analysis, age above 65 years [hazard ratio (HR)=1.769, 95% confidence interval (CI)=1.025-3.052, P=0.041], heart failure (HR=4.242, 95% CI=2.335-7.705, P<0.001), and diabetes (HR=1.773, 95% CI=1.043-3.012, P=0.034) were the significant predictors. The cumulative incidence of the primary endpoint was significantly higher in patients with three risk factors (19.1%) than in those with one (2.2%) or two (3.0%) risk factors (P=0.001). The cumulative target-vessel revascularization rate was 8.4%, with the significant predictors being a diffuse long lesion (HR=1.626, 95% CI=1.129-2.340, P=0.009) and at least three implanted stents (HR=1.964, 95% CI=1.301-2.965, P=0.001).

CONCLUSION

Clinical parameters such as age, diabetes, and heart failure were independent predictors of the composite of cardiac death, myocardial infarction, and stent thrombosis, whereas angiographic or procedural parameters such as lesion length and number of implanted stents were predictors of target-vessel revascularization. Clinical outcomes after CTO intervention were worse in patients with multiple risk factors.

Influence about the flow of distal branch after intervention of the right coronary artery chronic total occlusion

OBJECTIVE

Limited data are available for the clinical outcomes after the recanalization of right coronary artery (RCA) chronic total occlusion (CTO). The study aims to assess the clinical outcomes in the antegrade flow of the distal branch after successful RCA CTO percutaneous coronary intervention (PCI).

METHODS

Between January 2002 and December 2012, 538 patients who underwent RCA CTO PCI were enrolled. The clinical outcomes as myocardial infarction (MI), target vessel revascularization, cardiac death, major adverse cardiac events, and all-cause mortality, were compared to the antegrade flow of distal branch after successful RCA CTO PCI.

RESULTS

The CTOs were located in proximal segments (57.6%), mid segments (27.5%) and distal segments (14.9%). The average Syntax score was 18.4±9.6 and 47.8% patients had a Syntax score greater than 27.5. A total of 62.8% patients had final thrombolysis of myocardial infarction (TIMI)-3 flow of distal branch, 16.9% patients had final TIMI-3 flow of only one major branch, 11.3% patients had TIMI-1-2 flow, and 8.9% patients had no antegrade flow. The incidence of periprocedural MI was lower in both side branches were preserved (13.9% vs. 23.0% and 18.8%, p=0.01). The clinical outcomes were similar between the groups with and without good antegrade flow of distal side branch. End stage renal disease (ESRD) and left ventricular ejection fraction (LVEF) <40% predicted three-year cardiac death.

CONCLUSIONS

There is no significant difference of clinical outcomes when distal side branches of RCA are recanalized successfully. ESRD and LVEF <40% were the predictors for three-year cardiac death.