Impact of proctoring on success rates for percutaneous revascularisation of coronary chronic total occlusions

Chronic Total Occlusions: A State-of-the-Art Review

The percutaneous management of chronic total occlusions (CTO) is a well-established sub-specialty of Interventional Cardiology, requiring specialist equipment, training, and techniques. The heterogeneity of approaches in CTO has led to the generation of multiple algorithms to guide operators in their management. The evidence base for management of CTOs has suffered from inconsistent descriptive and quantitative terminology in defining the nature of lesions and techniques utilised, as well as seemingly contradictory data about improvement in ventricular function, symptoms of angina, and mortality from large-scale registries and randomised controlled trials. Through this review, we explore the history of CTO management and its supporting evidence in detail, with an outline of limitations of CTO-percutaneous coronary intervention and a look at the future of this growing field within cardiology.

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.

The Utility of CT Coronary Angiography in Chronic Total Occlusion Percutaneous Coronary Intervention

Chronic total occlusion (CTO) of the coronary arteries is a relatively common finding in routine coronary angiography. Of late, there has been considerable improvement in the success rate of percutaneous intervention for coronary CTO, attributed to technological advancement and skills development. CT coronary angiogram (CTCA) is a simple, non-invasive, and cost-effective test that aids in the diagnosis and management of coronary artery disease, including CTOs. The development of multi-slice CT and the use of 3D volume rendering images has revolutionised the diagnostic abilities of CTCA, with improvements in imaging quality and detailed anatomical and morphological characterisation of the plaque disease. In CTO percutaneous intervention, CTCA is used in pre-procedural planning, applying scoring systems to predict the likely success of the intervention as well as the post-procedural evaluation and follow-up. This review examines the different uses of CTCA in CTO intervention, its impact on successful recanalisation and the areas for future consideration.

Institutional Volume and Initial Results for Endovascular Treatment for Chronic Occlusive Lower-Extremity Artery Disease: A Report From the Japanese Nationwide Registry

PURPOSE

Chronic total occlusion (CTO) remains as a major target for endovascular treatment (EVT) in improving symptomatic lower-extremity artery disease (LEAD). However, despite the technical demand and learning curve for the procedure, volume-outcome relationship of EVT targeted for CTO in symptomatic LEAD remains unclear.

MATERIALS AND METHODS

Data were obtained from a nationwide registry for EVT procedures limited to the Japanese Association of Cardiovascular Intervention and Therapeutics between January 2018 and December 2020 from 660 cardiovascular centers in Japan. In total, 96 099 patients underwent EVT for symptomatic LEAD, and 41 900 (43.6%) underwent CTO-targeted EVTs during the study period. Institutional volume was classified into quartiles. The association of institutional volumes with short-term outcomes was explored using the generalized linear mixed model using a logit link function, in which, interinstitution variability was used as a random effect.

RESULTS

The median institutional volume for all EVT cases per quartile was 29, 68, 125, and 299 cases/year for the first, second, third, and fourth quartiles, respectively. With each model analysis, the adjusted odds ratios (ORs) for technical success were significantly lower in patients who underwent EVT in institutions within the first quartile (<52 cases/year) than in the other quartiles (P < .01, respectively). On the contrary, the adjusted ORs for procedural complications were significantly higher in the first and second quartiles than in the third and fourth quartiles (P < .01, respectively).

CONCLUSION

In contemporary Japanese EVT practice, a higher institutional volume but not operator volume was associated with a higher technical success rate and a lower procedural complication rate in patients with symptomatic LEAD involving CTO lesions.

CLINICAL IMPACT

EVT for CTO lesions is still challenging for clinicians because of difficulties of wire/devise crossing or high procedural complications rate. Our study demonstrated that a higher institutional volume but not operator volume was associated with a higher technical success rate and a lower procedural complication rate in patients with symptomatic LEAD involving CTO lesions. In contemporary Japanese practice, a higher institutional experience has better impacts on short-term clinical outcomes. Future research should determine the relationship between institutional volume and long-term clinical outcomes.

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.

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.

Sex-Based Differences in Coronary and Structural Percutaneous Interventions

In the current state of interventional cardiology, the ability to offer advanced therapies to patients who historically were not surgical candidates has grown exponentially in the last few decades. As therapies have expanded in complex coronary and structural interventions, the nuances of treating certain populations have emerged. In particular, the role of sex-based anatomic and outcome differences has been increasingly recognized. As guidelines for cardiovascular prevention and treatment for certain conditions may vary by sex, therapeutic interventions in the structural and percutaneous coronary areas may also vary. In this review, we aim to discuss these differences, the current literature available on these topics, and areas of focus for the future.

The impact of incomplete revascularization on early and late outcomes in ST-elevation myocardial infarction

BACKGROUND

In ST-elevation myocardial infarction (STEMI) in patients with multivessel disease, there is a lack of consensus regarding the importance of complete revascularization and the timing of treatment of nonculprit stenoses. Our objective was to investigate the impact of incomplete revascularization in STEMI patients using the residual Synergy Between PCI with TAXUS and Cardiac Surgery score (rSS) to define completeness of revascularization.

METHODS

This study examined associations between incomplete revascularization, determined by the rSS, and the combined outcome of cardiac death and myocardial infarction (MI). Patients were divided into groups: rSS = 0 (complete revascularization), rSS = 1-8 (incomplete revascularization with a low burden of residual disease), or rSS >8 (incomplete revascularization with a high burden of residual disease).

RESULTS

The rSS score was calculated in 589 consecutive patients; 25% had an rSS of 0, 42% rSS 1-8, and 33% rSS >8. At median follow-up of 3.5 years, cardiac death and MI occurred in 5% of rSS = 0 patients, 15% rSS = 1-8, and 26% with rSS >8 (P < .001). The rSS was powerful independent predictor of cardiac death and MI (hazard ratio 5.05, CI 2.89-12.00, rSS >8 vs rSS 0, P < .001 and hazard ratio 2.96, CI 1.31-6.69, rSS = 1-8 vs rSS = 0, P = .009), respectively, and an independent predictor of mortality, MI, unplanned revascularization, and major adverse cardiovascular events.

CONCLUSIONS

In patients with STEMI, the rSS independently predicts cardiac death and MI. Patients with an rSS >8 had substantially higher rates of cardiac death or MI. The rSS can be used to define incomplete revascularization in STEMI and predict adverse outcomes.

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.

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).

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.

Rapid initiation of fetal therapy services with a system of learner-centred training under proctorship: the National University Hospital (Singapore) experience

INTRODUCTION

Management of complicated monochorionic twins and certain intrauterine structural anomalies is a pressing challenge in communities that still lack advanced fetal therapy. We describe our efforts to rapidly initiate selective feticide using radiofrequency ablation (RFA) and selective fetoscopic laser photocoagulation (SFLP) for twin-to-twin transfusion syndrome (TTTS), and present the latter as a potential model for aspiring fetal therapy units.

METHODS

Five pregnancies with fetal complications were identified for RFA. Three pregnancies with Stage II TTTS were selected for SFLP. While RFA techniques utilising ultrasonography skills were quickly mastered, SFLP required stepwise technical learning with an overseas-based proctor, who provided real-time hands-off supervision.

RESULTS

All co-twins were live-born following selective feticide; one singleton pregnancy was lost. Fetoscopy techniques were learned in a stepwise manner and procedures were performed by a novice team of surgeons under proctorship. Dichorionisation was completed in only one patient. Five of six twins were live-born near term. One pregnancy developed twin anaemia-polycythaemia sequence, while another was complicated by co-twin demise.

DISCUSSION

Proctor-supervised directed learning facilitated the rapid provision of basic fetal therapy services by our unit. While traditional apprenticeship is important for building individual expertise, this system is complementary and may benefit other small units committed to providing these services.

Comparison of Characteristics and Complications in Men Versus Women Undergoing Chronic Total Occlusion Percutaneous Intervention

Gender differences exist in clinical outcomes after routine percutaneous coronary intervention (PCI), but studies reporting such outcomes after chronic total occlusion (CTO) PCI are limited. We assessed the characteristics and outcomes of female patients undergoing CTO PCI. We retrospectively analyzed a dedicated national (United Kingdom) prospective CTO database from 2011 to 2015 for outcomes and characteristics of female patients undergoing CTO PCI (unmatched and propensity matched). Female patients constituted 20.5% (n = 260 of 1,271) of the unmatched cohort and 33.3% (n = 233 of 699) of the matched cohort and were more likely to be older (women aged >70 years, 48% in the unmatched and 45% in the matched cohort). An increased inhospital complication rate was observed in female patients (unmatched: 10% women vs 4.45% men, p = 0.0012, and matched 9.87% women vs 3.86% men, p = 0.0032). Coronary perforation, bleeding, and contrast-induced nephropathy were more frequently observed in female patients. Femoral access site with >6 French sheath was associated with an increased risk of bleeding. Presence of calcification in the CTO artery was associated with coronary perforation (grade III) in female patients in the matched cohort (p = 0.007). Female patients undergoing CTO PCI were older and experienced increased of inhospital complications. Increased awareness of these complications could influence the selection of access site and sheath size, the need for prehydration, judicious choice of balloon size, collateral selection, and wire placement in female patients undergoing CTO PCI.

Hybrid Approach to Percutaneous Coronary Intervention to Treat Chronic Total Occlusions

The hybrid approach is a systematic algorithm-led percutaneous coronary intervention strategy based on the identification of key anatomical features on coronary angiography to treat chronic total occlusions. The aims of this approach are to provide a standardised tool for physician training and programme development, avoiding futile strategies to improve safety, procedural success and reduce the contrast and radiation required to complete the case.