Utility of Intravascular Ultrasound in Percutaneous Revascularization of Chronic Total Occlusions: An Overview

The Role of Coronary Imaging in Chronic Total Occlusions: Applications and Future Possibilities

Chronic total occlusions (CTOs) represent a challenging scenario in coronary artery disease (CAD). The prevalence of CTOS in patients undergoing coronary angiography underscores the need for effective diagnostic and therapeutic strategies. Coronary angiography, while essential, offers limited insights into lesion morphology, vessel course, and myocardial viability. In contrast, coronary imaging techniques-including optical coherence tomography (OCT), intravascular ultrasound (IVUS), and coronary computed tomography angiography (CCTA)-provide comprehensive insights for each stage of CTO percutaneous coronary intervention (PCI). OCT facilitates the assessment of plaque morphology and stent optimization, despite low evidence and several limitations in CTO-PCI. IVUS offers deeper penetration, allowing managing proximal cap scenarios and guiding subintimal navigation. CCTA provides a non-invasive, three-dimensional view of coronary anatomy, enabling the precise evaluation of myocardial mass at risk and detailed procedural planning. Despite their individual limitations, these imaging modalities have enhanced the success rates of CTO-PCI, thus reducing procedural and long-term complications and improving patient outcomes. The future of CTO management lies in further technological advancements, including hybrid imaging, artificial intelligence (AI) integration, and improved fusion imaging. These innovations promise to refine procedural precision and personalize interventions, ultimately improving the care of patients with complex coronary artery disease.

Case report: intravascular ultrasound-guided entry to an anomalous highly angulated circumflex coronary artery originating from the right sinus of Valsalva

Background

Anomalous coronary arteries originating from the contralateral sinus of Valsalva constitute a rare congenital anomaly. Most of such anomalous coronary arteries exhibit slit-like orifice that are often compounded by external compressive factors. Consequently, percutaneous coronary intervention (PCI) of these vessels poses considerable challenges, both in terms of cannulation but also intervention in often acutely angulated vessels.

Case summary

A 61-year-old man, with a history of previous coronary artery bypass graft surgery and PCI presented with a history consistent with unstable angina. Notably, the left circumflex artery (LCX) in this individual exhibited an anomalous origin. Due to unfavourable anatomy and ambiguous LCX ostium take-off, previous operators had elected PCI of the saphenous vein graft (SVG) anastomosed to the obtuse marginal branch. A computed tomography scan on this occasion confirmed occlusion of the SVG and defined precise origin of anomalous coronary artery. Real-time live intravascular ultrasound (IVUS) positioned in the ascending aorta, in the right sinus of Valsalva, allowed visualization of the origin and wiring of the anomalous circumflex coronary artery and also facilitated successful PCI.

Discussion

As far as we are aware, this is the first description of IVUS assisted wiring of an anomalous coronary artery. Intravascular ultrasound also facilitated decision making in this complex angioplasty of an angulated and heavily diseased circumflex coronary artery.

Development and validation of a nomogram for major adverse cardiovascular events after chronic total occlusion percutaneous coronary intervention for ischemic heart failure

BACKGROUND

Chronic total occlusion percutaneous coronary intervention (CTO-PCI) is an available means of revascularization in patients with ischemic heart failure (IHF). However, the prognosis of IHF patients undergoing CTO-PCI remains unclear due to the lack of reliable clinical predictive tools.

AIM

This study aimed to establish a nomogram for major adverse cardiovascular events (MACE) after CTO-PCI in IHF patients.

METHODS

Sixty-seven potential predictive variables for MACE in 560 IHF patients undergoing CTO-PCI were screened using least absolute shrinkage and selection operator regression. A nomogram was constructed based on multivariable Cox regression to visualize the risk of MACE, and then evaluation was carried out using the concordance index (C-index), time-independent receiver operating characteristic (timeROC) curves, calibration curves, and decision curve analysis (DCA).

RESULTS

During a median follow-up of 32.0 months, there were 208 MACE occurrences. Seven variables were selected for nomogram construction: age, left ventricular ejection fraction, left ventricular end-diastolic diameter, N-terminal precursor B-type diuretic peptide, bending, and use of intravascular ultrasound and beta-blockers. The C-index was 0.715 (0.680-0.750) and the internal validation result was 0.715 (0.676-0.748). The timeROC area under the curve at 6 months, 1 year, and 2 years was 0.750 (0.653-0.846), 0.747 (0.690-0.804), and 0.753 (0.708-0.798), respectively. The calibration curves and DCA showed the nomogram had acceptable calibration and clinical applicability.

CONCLUSIONS

We developed a simple and efficient nomogram for MACE after CTO-PCI in IHF patients, which helps in early risk stratification and postoperative management optimization.

Impact of Bifurcation Involvement and Location in Chronic Total Occlusion Percutaneous Coronary Intervention: Insights From the EuroCTO Registry

Bifurcation involvement close to or within the occluded segment poses increasing difficulties for chronic total occlusion (CTO)-percutaneous coronary intervention (PCI). However, this variable is not considered in the angiography-based CTO scoring systems nor has been extensively investigated in large multicenter series. Accordingly, we analyzed a CTO-PCI registry involving 92 European centers to explore the incidence, angiographic and procedural characteristics, and outcomes specific to CTO-PCIs with bifurcation involvement. A total of 3,948 procedures performed between January and November 2023 were examined (33% with bifurcation involvement). Among bifurcation lesions, 38% and 37% were located within 5 mm of the proximal and distal cap, respectively, 16% within the CTO body, and in 9% of cases proximal and distal bifurcations coexisted. When compared with lesions without bifurcation involvement, CTO bifurcation lesions had higher complexity (J-CTO 2.33 ± 1.21 vs 2.11 ± 1.27, p <0.001) and were associated with higher use of additional devices (dual-lumen microcatheter in 27.6% vs 8.4%, p <0.001, and intravascular ultrasound in 32.2% vs 21.7%, p <0.001). Radiation dose (1,544 [836 to 2,819] vs 1,298.5 [699.1 to 2,386.6] mGy, p <0.001) and contrast volume (230 [160 to 300] vs 190 [130 to 250] ml, p <0.001) were also higher. Technical success was similar (91.5% with bifurcation involvement vs 90.4% without bifurcation involvement, p = 0.271). However, the bifurcation lesions within the CTO segment (intralesion) were associated with lower technical success than the other bifurcation-location subgroups (83.7% vs 93.3% proximal, 93.4% distal, and 89.0% proximal and distal, p <0.001). On multivariable analysis, the presence of an intralesion bifurcation was independently associated with technical failure (odds ratio 2.04, 95% confidence interval 1.24 to 3.35, p = 0.005). In conclusion, bifurcations are present in approximately one-third of CTOs who underwent PCI. PCI of CTOs with bifurcation can be achieved with high success rates except for bifurcations within the occluded segment, which were associated with higher technical failure.

Antegrade Wire Tracking of the Retrograde Tract (ATRT): A Novel Technique for Percutaneous Coronary Intervention for Chronic Total Occlusion

BACKGROUND

Chronic total occlusion (CTO) lesions are the most challenging subset of coronary lesions. For lesions with a failed antegrade approach, the initial retrograde, followed by a combined retrograde and antegrade approach, remains the mainstay of therapy.

OBJECTIVE

The study evaluated a technique of initial retrograde followed by an antegrade approach to treat lesions with a failed antegrade approach.

METHODS

We have adopted this technique to treat 31 CTO lesions with a failed antegrade approach, where a floppy wire was advanced antegrade through the tract created by a retrograde balloon advanced over the retrograde wire (antegrade wire tracking of the retrograde tract (ATRT)), which was advanced into the aorta retrogradely.

RESULT

In 31 patients with failed antegrade approaches, the ATRT technique was tried, which was successful in 25 patients (the success rate was 80.6%). There was a failure to cross the microchannel in four patients, although angiographically, it looked promising. In two patients, it was impossible to advance the microcatheter or the smallest profile balloon retrogradely until the entire length of the CTO body. So, a reverse controlled antegrade and retrograde subintimal tracking (CART) was performed on these two patients excluded from the study.

CONCLUSION

ATRT is a useful technique for CTO percutaneous coronary intervention (PCI) for patients with failed antegrade approaches with acceptable success rates. The procedure is safe in terms of procedural complications.

Intravascular Imaging in the Diagnosis and Management of Patients With Suspected Intracoronary Pathologies: A CJC White Paper

Intravascular imaging has become an integral part of the diagnostic and management strategies for intracoronary pathologies. In this White Paper we summarize current evidence and its implications on the use of intravascular imaging in interventional cardiology practice. The areas addressed are planning and optimization of percutaneous coronary intervention, management of stent failure, and evaluation of ambiguous coronary lesions and myocardial infarction with nonobstructive coronary disease. The findings presented followed the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system in an expert consensus process that involved a diverse writing group vetted by a review group. Expert consensus was achieved around 9 statements. Use of intravascular imaging in guiding percutaneous revascularization is supported by high-quality evidence, particularly for lesions with increased risk of recurrent events or stent failure. Specific considerations for intravascular imaging guidance of intervention in left main lesions, chronic occlusion lesions, and in patients at high risk of contrast nephropathy are explored. Use of intravascular imaging to identify pathologies associated with stent failure and guide repeat intervention, resolve ambiguities in lesion assessment, and establish diagnoses in patients who present with myocardial infarction with nonobstructive coronary disease is supported by moderate- to low-quality evidence. Each topic is accompanied by clinical pointers to aid the practicing interventional cardiologist in implementation of the White Paper findings. The findings presented in this White Paper will help to guide the use of intravascular imaging toward situations in which the balance of efficacy, safety, and cost are most optimal.

Contemporary outcomes of chronic total occlusion percutaneous coronary intervention in Europe: the ERCTO registry

BACKGROUND

Percutaneous coronary interventions (PCI) of chronic total occlusions (CTO) have reached high procedural success rates thanks to dedicated equipment, evolving techniques, and worldwide adoption of state-of-the-art crossing algorithms.

AIMS

We report the contemporary results of CTO PCIs performed by a large European community of experienced interventionalists. Furthermore, we investigated the impact of different risk factors for procedural major adverse cardiac and cerebrovascular events (MACCE) and trends of employment of specific devices like dual lumen microcatheters, guiding catheter extensions, intravascular ultrasound and calcium-modifying tools.

METHODS

We evaluated data from 8,673 CTO PCIs included in the European Registry of Chronic Total Occlusion (ERCTO) between January 2021 and October 2022.

RESULTS

The overall technical success rate was 89.1% and was higher in antegrade as compared with retrograde cases (92.8% vs 79.3%; p<0.001). Compared with antegrade procedures, retrograde procedures had a higher complexity of attempted lesions (Japanese CTO [J-CTO] score: 3.0±1.0 vs 1.9±1.2; p<0.001), a higher procedural and in-hospital MACCE rate (3.1% vs 1.2%; p<0.018) and a higher perforation rate with and without tamponade (1.5% vs 0.4% and 8.3% vs 2.1%, respectively; p<0.001). As compared with mid-volume operators, high-volume operators had a higher technical success rate in antegrade and retrograde procedures (93.4% vs 91.2% and 81.5% vs 69.0%, respectively; p<0.001), and had a lower MACCE rate (1.47% vs 2.41%; p<0.001) despite a higher mean complexity of the attempted lesions (J-CTO score: 2.42±1.28 vs 2.15±1.27; p<0.001).

CONCLUSIONS

The adoption of different recanalisation techniques, operator experience and the use of specific devices have contributed to a high procedural success rate despite the high complexity of the lesions documented in the ERCTO.

SCAI Expert Consensus Statement on the Management of Calcified Coronary Lesions

The prevalence of calcification in obstructive coronary artery disease is on the rise. Percutaneous coronary intervention of these calcified lesions is associated with increased short-term and long-term risks. To optimize percutaneous coronary intervention results, there is an expanding array of treatment modalities geared toward calcium modification prior to stent implantation. The Society for Cardiovascular Angiography and Interventions, herein, puts forth an expert consensus document regarding methods to identify types of calcified coronary lesions, a central algorithm to help guide use of the various calcium modification strategies, tips for when using each treatment modality, and a look at future studies and trials for treating this challenging lesion subset.

Contemporary In-Hospital Outcomes of Chronic Total Occlusion Percutaneous Coronary Interventions: Insights from the MENATA (Middle East, North Africa, Turkey, and Asia) Chapter of the PROGRESS-CTO Registry

Chronic total occlusion (CTO) percutaneous coronary intervention (PCI) has been rapidly evolving in different parts of the world. We examined the clinical and angiographic characteristics and procedural outcomes of 1,079 consecutive CTO PCIs performed in 1,063 patients at 10 centers in the Middle East, North Africa, Turkey, and Asia regions between 2018 and 2022. The mean age was 61 ± 10 years and 82% of the patients were men. The prevalence of diabetes (49%) and previous PCI (50%) was high. The most common target vessel was the right coronary artery (51%), followed by the left anterior descending artery (33%) and the circumflex artery (15%). The mean Japanese CTO score was 2.1 ± 1.2 and mean PROGRESS-CTO (Prospective Global Registry for the Study of Chronic Total Occlusion Intervention) score was 1.2 ± 1.0. The technical and procedural success rates were high (91% and 90%, respectively) with a low incidence (1.6%) of in-hospital major adverse cardiac events. The incidence of perforation was 4.6% (n = 50): guidewire exit was the most common mechanism of perforation (48%) and 14 patients required pericardiocentesis (28%). Antegrade wire escalation was the most common crossing strategy used (91%), followed by retrograde approach (24%) and antegrade dissection and re-entry (12%). Median contrast volume, air kerma radiation dose, and fluoroscopy time were 300 (200 to 400) ml, 3.7 (2.0 to 6.3) Gy, and 40 (25 to 65) minutes, respectively. In conclusion, high success and acceptable complication rates are currently achieved at experienced centers in the Middle East, North Africa, Turkey, and Asia regions using a combination of crossing strategies.

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

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

CTO and Bifurcation Lesions: An Expert Consensus From the European Bifurcation Club and EuroCTO Club

Knowledge in the field of bifurcation lesions and chronic total occlusions (CTOs) has progressively improved over the past 20 years. Therefore, the European Bifurcation Club and the EuroCTO Club have decided to write a joint consensus statement to share general knowledge and practical approaches in this complex field. When percutaneously treating CTOs, bifurcation lesions with relevant side branches (SBs) are found in approximately one-third of cases (35% at the proximal cap, 38% at the distal cap, and 27% within the CTO body). Occlusion of a relevant SB is not rare and has been shown to be associated with procedural complications and adverse outcomes. Simple bifurcation rules are very useful to prevent SB occlusion, and provisional SB stenting is the recommended approach in the majority of cases: protect the SB as soon as possible by wiring it, respect the fractal anatomy of the bifurcation by using the 3-diameter rule, and avoid using dissection and re-entry techniques. A systematic 2-stent approach can be used if needed or sometimes to connect both branches of the bifurcation. The retrograde approach can be very useful to save a relevant SB, especially in the case of a bifurcation at the distal cap or within the CTO body. Intravascular ultrasound is also a very important tool to address the difficulties with bifurcations at the proximal or distal cap and sometimes also within the CTO segment. Double-lumen microcatheters and angulated microcatheters are crucial tools to resolve access difficulties to the SB or the main branch.

Utility of Guiding Catheter Extensions for Recanalization of Chronic Total Occlusions: A EuroCTO Club Expert Panel Report

Guiding catheter extensions (GCEs) have become indispensable tools in the modern approach to percutaneous coronary intervention (PCI). The support offered during complex PCI of uncrossable, or tortuous lesions is particularly valuable in the setting of chronic total occlusions (CTO), both for conventional anterograde wire escalation and for anterograde or retrograde dissection and re-entry techniques. This EuroCTO consensus document describes the use of GCE during CTO recanalization and provides a practical guide to anatomies and techniques in which these devices are applicable. We describe the peculiar features of the most-used device and the practical technique for GCE delivery in standard PCI; further specific indications for antegrade and retrograde CTO PCI are discussed in a specific section. In the antegrade approach, the GCEs may be useful to increase support or facilitate antegrade dissection and re-entry techniques, while in the retrograde approach for reverse controlled antegrade and retrograde tracking, to increase retrograde support for gear delivery, for treatment of CTO in bifurcation and ipsilateral externalization with a single guide catheter. The last section of the paper describes GCE-related complications, challenges, limitations, and future perspectives.

Percutaneous Coronary Intervention for Chronic Total Occlusion-Contemporary Approach and Future Directions

In the aging society, the issue of coronary chronic total occlusion (CTO) has become a challenge for invasive cardiologists. Despite the lack of clear indications in European and American guidelines, the rates of percutaneous coronary interventions (PCI) for CTO increased over the last years. Well-conducted randomized clinical trials (RCT) and large observational studies brought significant and substantial progress in many CTO blind spots. However, the results regarding the rationale behind revascularization and the long-term benefit of CTO are inconclusive. Knowing the uncertainties regarding PCI CTO, our work sought to sum up and provide a comprehensive review of the latest evidence on percutaneous recanalization of coronary artery chronic total occlusion.

Impact of proximal cap ambiguity on the procedural techniques and outcomes of chronic total occlusion percutaneous coronary intervention: Insights from the PROGRESS-CTO Registry

BACKGROUND

Proximal cap ambiguity is a key parameter in the global chronic total occlusion (CTO) percutaneous coronary intervention (PCI) crossing algorithm.

METHODS

We examined the baseline characteristics and procedural outcomes of 9718 CTO PCIs performed in 9498 patients at 41 US and non-US centers between 2012 and 2022.

RESULTS

Proximal cap ambiguity was present in 35% of CTO lesions. Patients whose lesions had proximal cap ambiguity were more likely to have had prior coronary artery bypass graft surgery (37% vs. 24%; p < 0.001). Lesions with proximal cap ambiguity were more complex with higher J-CTO score (3.1 ± 1.0 vs. 2.0 ± 1.2; p < 0.001) and lower technical (79% vs. 90%; p < 0.001) and procedural (77% vs. 89%; p < 0.001) success rates compared with nonambiguous CTO lesions. The incidence of major adverse cardiovascular events (MACE) was higher in cases with proximal cap ambiguity (2.5% vs. 1.7%; p < 0.001). The retrograde approach was more commonly used among cases with ambiguous proximal cap (50% vs. 21%; p < 0.001) and was more likely to be the final successful crossing strategy (29% vs. 13%; p < 0.001). The antegrade dissection and re-entry (ADR) "move-the-cap" techniques were also more common among cases with proximal cap ambiguity.

CONCLUSIONS

Proximal cap ambiguity in CTO lesions is associated with higher utilization of the retrograde approach and ADR, lower technical and procedural success rates, and higher incidence of in-hospital MACE.

Intravascular Imaging During Percutaneous Coronary Intervention: JACC State-of-the-Art Review

Coronary angiography has historically served as the gold standard for diagnosis of coronary artery disease and guidance of percutaneous coronary intervention (PCI). Adjunctive use of contemporary intravascular imaging (IVI) technologies has emerged as a complement to conventional angiography-to further characterize plaque morphology and optimize the performance of PCI. IVI has utility for preintervention lesion and vessel assessment, periprocedural guidance of lesion preparation and stent deployment, and postintervention assessment of optimal endpoints and exclusion of complications. The role of IVI in reducing major adverse cardiac events in complex lesion subsets is emerging, and further studies evaluating broader use are underway or in development. This paper provides an overview of currently available IVI technologies, reviews data supporting their utilization for PCI guidance and optimization across a variety of lesion subsets, proposes best practices, and advocates for broader use of these technologies as a part of contemporary practice.

[Contribution of intracoronary imaging in CTO PCI]

The interest in revascularization of chronic total occlusions (CTO) of the coronary arteries during the last decade has not waned. It is one of the latest challenges for percutaneous coronary interventions (PCI), requiring a specific organization of the patient pathway, dedicated equipment, and targeted medical expertise, now establishing CTO as a new discipline in interventional cardiology. Despite technical progress, the success rate of CTO-PCI is still lower than that of non-CTO-PCI, mainly due to guidewire failure. What can be the place of IVUS in CTO recanalization? IVUS offers a real-time cross-sectional image of the lumen and the vessel wall and meets all the criteria for assisting guidewire crossing. In addition, and as in any angioplasty of long and calcified complex lesions, IVUS participates in an optimal sizing of the stent and ensures its proper expansion. Optical coherence tomography (OCT) has no place, for multiple reasons, in the management of a CTO procedure but can help on remote control to ensure an optimal result, to validate the interest of a technique. Endocoronary imaging in CTO as in other complex situations is likely to optimize procedural results, to validate strategic options with the ultimate goal of improving clinical results.

Recanalisation of coronary chronic total occlusions

Percutaneous treatment of coronary chronic total occlusions (CTO) has advanced greatly since its advent in the late 1970s through the development of dedicated wires and microcatheters, the improved skills of highly experienced operators and the adoption of new sophisticated strategies to guide procedural planning. The contemporary procedural success rate is 80-90% with a reduction in complications. Although there has been no improvement in prognosis in randomised trials to date, they, and other controlled registries of thousands of patients, confirm the pivotal role of CTO recanalisation in the treatment of angina and dyspnoea and an improvement in quality of life. Despite this evidence, CTO recanalisation is grossly underutilised. This review reports a detailed overview of the history, indications and treatment strategies for CTO recanalisation and hopes to increase interest among new, and especially young, operators in this demanding, rapidly evolving field of interventional cardiology.

Use of intravascular ultrasound for optimal vessel sizing in chronic total occlusion percutaneous coronary intervention

Aim

The aim of this study is to provide evidence on how use of standardized intravascular ultrasound (IVUS) use impacts stent size choice in the setting of chronic total occlusion (CTO) percutaneous coronary intervention (PCI) compared to visual estimation.

Methods and results

Data of 82 consecutive patients who had successfully undergone IVUS-guided revascularization of CTO at the University Medical Center Mainz were analyzed. Angiography-based stent size prediction for the proximal and distal vessels was compared to the implanted stent diameter after IVUS assessment. Angiography-based stent size prediction for the proximal vessel was 3.09 ± 0.41, whereas IVUS use demonstrated larger vessel diameter, resulting in larger implanted stent diameter (3.24 ± 0.45, p &lt; 0.001). Proximal vessel stent size prediction was underestimated in the majority of patients by angiographic estimation. Angiography-based stent size prediction for the distal vessel was 2.79 ± 0.38, whereas IVUS use demonstrated larger vessel diameter, resulting in larger implanted stent diameter (2.92 ± 0.39, p &lt; 0.001).

Conclusion

Pre-stent IVUS assessment in CTO PCI provides important information on vessel morphology and size. Angiography-based stent size prediction for the proximal and distal vessels was frequently underestimated, IVUS use demonstrated larger vessel diameter, resulting in significantly larger implanted stent diameter.

Electric-Field-Based Guidance for Percutaneous Catheter Vessel Crossing

Percutaneous procedures to divert blood flow from one blood vessel to another can be performed with intravascular catheters but demand a method to align a crossing needle from one vessel to another. Fluoroscopic imaging alone is not adequate, and it is preferable to have a sensor on one catheter that detects the correct alignment of an incoming needle. This can be implemented by generating dipole electric fields from the crossing catheter which are detected by a receiving catheter in the target vessel and, thus, can calculate and display the degree of alignment, permitting the operator to rotate the crossing catheter to guarantee alignment when deploying a crossing needle. Catheters were built using this concept and evaluated in vitro. The results show that accurate alignment is achieved, and a successful crossing can be made. The concept is being further developed for further clinical evaluation.

The retrograde technique for recanalization of chronically occluded coronary arteries: Case series report

Introduction. Chronic total occlusion (CTO) of the coronary artery still represents one of the most challenging lesion subsets in the field of interventional cardiology. Considering the complexity and increased risk posed by the retrograde approach, it is most often performed after a failed antegrade approach. Case report. We present a series of cases describing the retrograde approach as a special technique for treating CTO of the coronary artery. All cases had some special characteristics that are part of a dedicated portfolio in every catheterization lab today. In our series of cases, all three percutaneous coronary interventions (PCI) with a different strategies of the retrograde approach and supported with rotational atherectomy or intravascular ultrasound finished with successful recanalization of CTO. Conclusion. In cases where there is the presence of ?interventional? collaterals, as well as when the antegrade approach is very difficult, the retrograde approach can increase the success rate of procedures. The retrograde approach requires a long learning curve as well as very skilled and experienced operators who are able to per-form the procedure independently.

CTO in Contemporary PCI

Percutaneous Coronary Intervention (PCI) of Chronic Total Occlusions (CTO) represents the most challenging procedure in modern endovascular treatments. In recent years, the success rate of CTO PCI has substantially improved, owing to increasing operator expertise and advancements in CTO equipment and algorithms as well as the development of expert consensus documents. In this review, we summarize existing evidence for CTO PCI, its success/ risk prediction scoring tools, procedural principles and complications and provide an insight into the future role of CTO PCI.

[Technical armamentarium for chronic total occlusion of coronary vessels]

Percutaneous revascularization of chronic total occlusion (CTO) of coronary vessels represents a major challenge for contemporary interventional cardiologists. In the last decade there has been an unprecedented effort towards the standardization of revascularization procedures for CTO of coronary vessels. This endeavour has been possible by virtue of the growing interest of various cardiological societies for this patient group. Along with supportive endovascular technologies and percutaneous devices specifically dedicated to this interventional target, the increasing experience of interventionalists enabled continuously growing success for revascularization of CTO of coronary vessels. This review article highlights the currently available tools as well as technologies, techniques and strategies for the percutaneous recanalization of CTO of coronary vessels.

Healing of iatrogenic double-barrel left main coronary artery dissection extending to the left anterior descending artery

Iatrogenic left main coronary artery (LMCA) dissection is a complication inadvertently caused by the interventional cardiologist and can have significant consequences. A 38-year-old man presented to hospital with non-ST-elevation myocardial infarction. Coronary angiography (CAG) revealed an obstructed proximal left circumflex artery (LCx) that was successfully treated with revascularization using a drug-eluting stent (DES). However, CAG after recanalization of the LCx demonstrated a spiral dissection of the left coronary artery from the mid-LMCA to the left anterior descending (LAD) artery and LCx. The dissection was classified as National Heart, Lung and Blood Institute type D in LAD and type F in LCx. Immediate exclusion stenting of the dissection flap by another DES and thrombolysis in myocardial infarction 3 flow were achieved in the LAD and LCx. The patient achieved hemodynamic stability with improvement in symptoms, despite residual dissection in the LAD. We, therefore, preferred careful observation over revascularization. The false lumen remained visible with a double-barrel appearance in the LAD on 6-month follow-up CAG, which disappeared at the 2-year follow-up. We report a rare case of a large double-barrel dissection that spontaneously occluded over time without any aggressive interventions. <Learning objective: Iatrogenic left main coronary artery (LMCA) dissection is a rare but potentially life-threatening complication, with the associated risk of serious outcomes. Immediately after suffering a LMCA dissection, treatment strategies (conservative therapy, percutaneous coronary intervention, or coronary bypass grafting etc.) should be determined according to patient's symptoms and hemodynamic status. However, treatment strategies for chronic LMCA dissection are uncertain. Our case indicates that conservative therapy appears to be a potential option for the treatment of chronic asymptomatic and hemodynamically stable LMCA dissection.>.

A Clinical Analysis of the Treatment of Chronic Coronary Artery Occlusion With Antegrade Dissection Reentry

Objective: This study aimed to investigate the efficacy and safety of antegrade dissection re-entry (ADR) technique in the percutaneous coronary intervention (PCI) to open chronic total occlusion (CTO) lesions. Methods: The baseline, angiographic results, PCI success rate, and major adverse cardiac events (MACE) during the 12 months of follow-up were compared between 48 patients who did not use ADR in the treatment of CTO lesions (control group) and 50 patients who used ADR (treatment group). Results: The control group comprised 48 patients who had 52 CTO lesions, and the treatment group comprised 50 patients who had 58 CTO lesions. The success rate of PCI in the treatment group (89.7 vs. 71.2%, P = 0.047) was significantly higher than in the control group, where six patients had in-stent restenosis (ISR, ISR-CTO) that were all recanalized. The mean PCI time (71 ± 25 min vs. 95 ± 33 min, P = 0.041), X-ray exposure time (42 ± 17 min vs. 71 ± 22 min, P = 0.032), contrast agent dosage (98 ± 26 ml vs. 178 ± 63 ml, P = 0.029), MACE incidence during the 12 months of follow-up (22.0 vs. 41.7%, P = 0.046) and recurrent myocardial infarction incidence (10.0 vs. 27.1%, P = 0.047) were significantly lower in the treatment group than in the control group. The differences were all statistically significant. Conclusion: It is safe and effective to use the ADR technique in PCI for coronary artery CTO lesions. The technique shortens the operation time, reduces the radiation dose of doctors and patients and the use dose of contrast agents, and improves patients' prognoses.

In-Stent CTO Percutaneous Coronary Intervention: Individual Patient Data Pooled Analysis of 4 Multicenter Registries

OBJECTIVES

The authors sought to examine the outcomes of percutaneous coronary intervention (PCI) for in-stent restenosis (ISR) chronic total occlusions (CTOs).

BACKGROUND

The outcomes of PCI for ISR CTOs have received limited study.

METHODS

The authors examined the clinical and angiographic characteristics and procedural outcomes of 11,961 CTO PCIs performed in 11,728 patients at 107 centers in Europe, North America, Latin America, and Asia between 2012 and 2020, pooling patient-level data from 4 multicenter registries. In-hospital major adverse cardiovascular events (MACE) included death, myocardial infarction, stroke, and tamponade. Long-term MACE were defined as the composite of all-cause death, myocardial infarction, and target vessel revascularization.

RESULTS

ISR represented 15% of the CTOs (n = 1,755). Patients with ISR CTOs had higher prevalence of diabetes (44% vs. 38%; p < 0.0001) and prior coronary artery bypass graft surgery (27% vs. 24%; p = 0.03). Mean J-CTO (Multicenter CTO Registry in Japan) score was 2.32 ± 1.27 in the ISR group and 2.22 ± 1.27 in the de novo group (p = 0.01). Technical (85% vs. 85%; p = 0.75) and procedural (84% vs. 84%; p = 0.82) success was similar for ISR and de novo CTOs, as was the incidence of in-hospital MACE (1.7% vs. 2.2%; p = 0.25). Antegrade wiring was the most common successful strategy, in 70% of ISR and 60% of de novo CTOs, followed by retrograde crossing (16% vs. 23%) and antegrade dissection and re-entry (15% vs. 16%; p < 0.0001). At 12 months, patients with ISR CTOs had a higher incidence of MACE (hazard ratio: 1.31; 95% confidence interval: 1.01 to 1.70; p = 0.04).

CONCLUSIONS

ISR CTOs represent 15% of all CTO PCIs and can be recanalized with similar success and in-hospital MACE as de novo CTOs.

Distal Re-Entry to Treat Lower Limb Chronic Total Occlusions Using a Novel Electrically Guided Re-Entry Catheter

Introduction

Endovascular treatment of challenging infra-inguinal peripheral vascular disease is increasingly common because of new techniques and improved tools. The use of a novel electrically guided 5 F re-entry catheter is presented. By emitting a minute electrical field, detected by a target wire inserted from an opposing access, the catheter's orientation is accurately displayed to the operator, allowing precise re-entry without the need for fluoroscopic alignment.

Report

An 84 year old man with tissue loss was treated for a long occlusion of the superficial femoral artery and tibial vessels. Successful subintimal recanalisation was achieved with the help of the ePATH re-entry catheter, restoring inline flow to the foot.

Conclusion

This re-entry catheter benefits from an intuitive alignment method, smaller profile, and operator adjustable needle travel, making it a versatile tool for endovascular cases.

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Heavily calcified CTOs are challenging to treat endovascularly.

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A novel electrically guided re-entry catheter is presented.

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This 5F device doesn’t need fluoroscopic alignment and needle is adjustable in length.

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The re-entry system requires bidirectional approach to safely cross into true lumen.

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The first in human use of this device in a complex popliteal occlusion is described.

Safety and outcomes of combined carbon dioxide angiography and OCT-guided femoro-popliteal chronic total occlusion crossing and directional atherectomy in patients with chronic kidney disease

BACKGROUND

Carbon dioxide angiography with addition of optical coherence tomography imaging may improve procedural success and clinical outcomes in patients with peripheral artery disease and chronic kidney disease.

METHODS

Single-center, retrospective analysis of patients with chronic kidney disease who underwent carbon dioxide angiography and optical coherence tomography-guided chronic total occlusion crossing and/or optical coherence tomography-guided directional atherectomy was performed. Patient and procedure-related characteristics, along with peri- and one-year post-procedural major adverse events, were analyzed.

RESULTS

A total of 18 vessels in 11 patients, with mean age 70 years were treated. All had co-morbidities such as hypertension, hyperlipidemia, had history or were current smokers with baseline peripheral artery disease. Majority were diabetic with coronary disease (82%); 55% baseline chronic kidney disease IV, 55% Rutherford class III and 45% class IV. Contrast was used in only two patients. Mean total fluoroscopy time and radiation dose was 24.1 min and 249.2 mGY, respectively. Half of the lesions were femoro-popliteal chronic total occlusions, and Ocelot catheter was used to cross seven of nine chronic total occlusions and was successful in six. Adjunctive optical coherence tomography-guided directional atherectomy was performed in 8 of 11 patients. Only two adverse events occurred: one clinically significant event of slow-flow intra-procedurally and one target limb revascularization within one year of index procedure in a vessel different than prior treated. Optical coherence tomography imaging in both chronic total occlusion-crossing and atherectomy resulted in 10-min mean fluoroscopy reduction time and 32 mGY reduction in radiation dose.

CONCLUSION

Carbon dioxide angiography with the addition of optical coherence tomography imaging for chronic total occlusion crossing and/or optical coherence tomography-guided directional atherectomy reduced the need for contrast agents, total fluoroscopy time, and radiation exposure in patients with peripheral artery disease and baseline chronic kidney disease.

Impact of Guidewire Route on Severe Dissection After Balloon Angioplasty for Femoropopliteal Chronic Total Occlusion Lesions: An Intravascular Ultrasound Analysis

OBJECTIVE

To determine the impact of the guidewire route on severe dissection after balloon angioplasty for femoropopliteal chronic total occlusion (CTO) lesions using a new intravascular ultrasound (IVUS) assessed classification scheme corresponding to a conventional angiographic classification scheme.

METHODS

Images for 21 femoropopliteal CTO lesions treated endovascularly between May 2018 and December 2019 were used for analysis. IVUS images after guidewire passage and those after balloon angioplasty were evaluated at 1 cm intervals. Cross sectional images were obtained (n = 219) and divided into two groups by the guidewire route: those in which the guidewire passed through the inner half of the luminal radius (central wiring group, 139 cross sectional images) and those in which the guidewire passed through the outer half of the luminal radius (eccentric wiring group, 80 cross sectional images). Angiographically severe dissection was defined as Type C or greater according to the National Heart, Lung, and Blood Institute classification, to which six dissection morphology patterns were applied based on IVUS images (Types A - E2).

RESULTS

Central wiring was achieved in an average of 69.6 ± 28.0% of the CTO length from per limb analysis. Among the IVUS assessed dissection morphology patterns, Types D - E2 were more frequently correlated with angiographically severe dissection than were Types A - C (57.5% vs. 13.7%, p < .001). Multivariable analysis showed that soft plaque was a predictive factor for (odds ratio [OR] 2.14; 95% confidence interval [CI] 1.007 - 4.72; p = .048) and central wiring was a protective factor (OR 0.27; 95% CI 0.14 - 0.49; p < .001) against Type D - E2 dissection patterns assessed by IVUS after balloon angioplasty.

CONCLUSION

Lesions with Type D - E2 dissection patterns assessed by IVUS were correlated with angiographically severe dissection. Central wiring may be useful for preventing severe dissection after balloon angioplasty for femoropopliteal CTO lesions.

Impact of intravascular ultrasound on chronic total occlusion percutaneous revascularization

AIM

We sought to investigate the impact of IVUS use on chronic total occlusion (CTO) PCI using data from a contemporary registry of consecutive patients and applying a propensity score matching analysis.

METHODS AND RESULTS

We evaluated 514 successful CTO-PCIs, median age: 67 years (IQR: 58-73), 83.5% males. IVUS-guided PCI was performed in 184 (35.8%) of cases. After using 1:1 propensity matching score analysis, two groups of 182 patients each (IVUS-guided vs. angiography-guided CTO-PCI group) were produced to form the study population. In the IVUS-guided group the median maximum stent diameter was larger and the median total stented segment was longer compared to the angiography-guided group [(3.5 mm, IQR: 3.0-4.0 vs. 3.2 mm, IQR: 3.0-3.5, p < 0.001) and (60.0 mm, IQR: 38.0-91.3 vs. 38.0 mm, IQR: 32.0-70.5, p < 0.001), respectively]. In the IVUS-guided group, retrograde recanalization was more frequently encountered compared to the angiography-guided PCI group (30.2% vs. 20.9%, p = 0.04). Procedural time was significantly longer in the IVUS-guided group, without any difference in fluoroscopy time, radiation dose and contrast volume. Multivariate linear regression analysis showed that IVUS use was the strongest independent factor associated with larger maximum diameter stents (p < 0.001) and a strong independent predictor for total stented segment length during CTO-PCI (p < 0.001). Up to 8 years follow-up, there was no difference in the incidence of the composite endpoint of all-cause death, cardiac death, myocardial infarction and target vessel revascularization between the IVUS-guided PCI and the angiography-guided PCI groups (hazard ratio: 13.7% vs. 15.9%, respectively, log-rank: p = 0.67, median follow-up time: 49.0 months, IQR: 33.0-67.0).

CONCLUSIONS

Use of IVUS in CTO-PCI was associated with larger stent diameter and longer stented segments. Despite more frequent use of IVUS in retrograde CTO-PCI, there was no difference in long-term adverse events between IVUS and angiography CTO-PCI groups; nevertheless, the study was not powered to assess clinical outcomes.

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

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

Intravascular Imaging-Guided Percutaneous Coronary Intervention

Despite consistent clinical data supporting the use of intravascular imaging with percutaneous coronary intervention, utilization remains low. A practical and standardized approach to incorporating intravascular imaging with percutaneous coronary intervention may overcome the barriers to utilization. This review focuses on basic image interpretation with intravascular ultrasound and optical coherence tomography and proposes an algorithmic approach to stent sizing and optimization. Incorporation of this strategic method for percutaneous coronary intervention may aid in the greater adoption of intravascular imaging for percutaneous coronary intervention.

Fundamentals and role of intravascular ultrasound in percutaneous coronary intervention

Intravascular ultrasound (IVUS) is a catheter-based invasive imaging modality that has become an essential adjunctive tool to percutaneous coronary intervention (PCI) over the past 20 years. Clinical applications of IVUS in PCI include assessment of lesion severity, characterizing plaque morphology, optimization of acute stent results and clarification of mechanisms of stent failure. Numerous meta-analyses of large observational and randomized studies support the role of IVUS-guided PCI in reducing short and long-term adverse outcomes, including mortality and stent failure, particularly in patients receiving drug-eluting stents (DESs) and in complex lesion subsets. The current review provides a summary of the fundamental aspects and current clinical roles of IVUS in coronary intervention.

Efficacy of Coronary Computed Tomography Angiography for the De Novo Detection of Chronic Total Occlusion Prior to Coronary Angiography: A Preliminary and Retrospective Study

Coronary computed tomography angiography (CCTA) offers high-resolution anatomic characterization of the coronary vasculature but may be suboptimal for lesions dependent on real-time visualization of flow including chronic total occlusion (CTO). In CTOs, heavy calcification and distal vessel opacification from collateralization may confound luminal assessment. Several studies have examined the role of CCTA in characterizing known CTOs to guide percutaneous coronary intervention (PCI). However, the efficacy of CCTA in the de novo diagnosis of CTOs prior to coronary angiography (CAG) has not been demonstrated. A total of 233 consecutive patients who presented for CAG within a 3-month period of having CCTA were retrospectively reviewed. Those patients with prior diagnosis of CTO or prior bypass of the occluded vessels were excluded. Sensitivity and specificity analysis of CCTA in identifying CTOs using CAG as the gold standard was performed. The prevalence of CTO was 21.11% in the population that met criteria for analysis (n = 199). The sensitivity of CCTA in predicting CTO was 57.1%, while the specificity was 96.8%. The positive predictive value and negative predictive value of CCTA in detection of CTO were 82.8 and 89.4%, respectively. Our study shows that CCTA has excellent specificity but poor sensitivity in the detection of CTO thus limiting its clinical use in de novo diagnosis. Further studies to determine the effect of de novo CTO diagnosis on clinically important procedural factors, such as radiation exposure, contrast use, and need for repeat procedures, are warranted and may implicate a role for CCTA in this setting.

Long-Term Outcomes of Coronary Stenting With and Without Use of Intravascular Ultrasound

OBJECTIVES

This study sought to explore if intravascular ultrasound (IVUS) use in real-world patients is associated with improved long-term outcomes of percutaneous coronary intervention (PCI).

BACKGROUND

The benefit of IVUS use with PCI in real world is uncertain.

METHODS

We identified Medicare patients who underwent PCI from 2009 to 2017 and evaluated the association of IVUS use with long-term risk of mortality, myocardial infarction (MI), and repeat revascularization. We used propensity score matching and inverse probability weighting to adjust for baseline characteristics. To account for hospital effects, patients undergoing IVUS-guided PCI were matched to non-IVUS patients in the same hospital and year. Sensitivity analyses comparing outcomes with and without IVUS in stable coronary artery disease and acute coronary syndrome, PCI with bare-metal stents and drug-eluting stents, complex and noncomplex PCI, and facilities with 1% to 5%, 5% to 10%, and >10% IVUS use were performed.

RESULTS

Overall, IVUS was used in 5.6% of all PCI patients (105,787 out of 1,877,177 patients). Patients with IVUS-guided PCI had a higher prevalence of most comorbidities. In the propensity matched analysis, IVUS-guided PCI was associated with lower 1-year mortality (11.5% vs. 12.3%), MI (4.9% vs. 5.2%), and repeat revascularization (6.1% vs. 6.7%) (p < 0.001 for all). In inverse probability weighting analysis with a median follow-up of 3.7 years (interquartile range: 1.7 to 6.4 years), IVUS-guided PCI was associated with a lower risk of mortality (adjusted hazard ratio [aHR]: 0.903; 95% confidence interval [CI]: 0.885 to 0.922), MI (aHR: 0.899; 95% CI: 0.893 to 0.904), and repeat revascularization (aHR: 0.893; 95% CI: 0.887 to 0.898) (p < 0.001 for all). These findings were consistent in all subgroups in sensitivity analyses.

CONCLUSIONS

In this contemporary U.S. Medicare cohort, the use of IVUS guidance in PCI remains low. Use of IVUS is associated with lower long-term mortality, MI, and repeat revascularization.

Magnetically Actuated Forward-Looking Interventional Ultrasound Imaging: Feasibility Studies

OBJECTIVE

Interventional ultrasound imaging is a prerequisite for guiding implants and treatment within the hearts and blood vessels. Due to limitations on the catheter's diameter, interventional ultrasonic transducers have side-looking structures although forward-looking imaging may provide more intuitive and real time guidance in treating diseased sites ahead of catheters. To address the issue, a magnetically actuated forward-looking interventional ultrasound imaging device is implemented for the first time.

METHODS

A forward-looking catheter containing a 1 mm ring type focused 35 MHz ultrasound transducer and a micro magnet, was fabricated. For imaging, the transducer was placed at the center of four electromagnetic coils positioned on four sides of a squared acrylic housing. By modifying the magnetic field, the catheter tip could be remotely translated for sector scanning.

RESULTS

The scanning angle could reach up to 3° in 1 Hz with 15 mT, while wider angles of 5° could be achieved with a higher magnetic field of 25 mT for ex-vivo imaging. The position of the transducer could be detected by monitoring the motion with a CCD camera, mimicking clinical X-ray imaging. In the wire target and tissue mimicking phantom studies, the measured hole size, spatial resolution and distance between wires by the proposed system were comparable with the values from a linear scanner. Multi-frame real time data acquisition was demonstrated via ex-vivo imaging on a pig's coronary artery.

CONCLUSION/SIGNIFICANCE

The feasibility of magnetically actuated forward-looking interventional ultrasound imaging was demonstrated. The remote-controlled scanning method may allow to simplify the structures of forward-looking interventional ultrasound imaging catheters.

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.

Current clinical use of intravascular ultrasound imaging to guide percutaneous coronary interventions

During the past three decades, since the invention of intravascular ultrasound (IVUS), it has become increasingly important as daily clinical applications. However, it evolved with no Japanese standards for the measurement of images, the index of percutaneous coronary intervention (PCI) procedures, and the reporting of results. Accordingly, the purpose of this review article is to provide an optimal and consistent approach to IVUS usage during PCI for clinicians and investigators.

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.

The antegrade dissection and re-entry technique as preparation of intravascular ultrasound guided re-wiring

Although the antegrade dissection and re-entry technique (ADR) with Stingray system is one of the procedures for percutaneous coronary intervention (PCI) of chronic total occlusion (CTO), it has some risk of side-branch occlusion. This article reports a CTO case in the left circumflex artery successfully treated with combination use of ADR subintimal tracking and intravascular ultrasound (IVUS)-guided re-wiring without side-branch occlusion. Antegrade approach with single-wire and parallel-wire technique was failed. Retrograde approach through ipsilateral collateral was also failed. Therefore, the ADR was attempted and Stingray wire crossed through at the distal site of posterolateral (PL) branch. To avoid PL branch occlusion, IVUS-guided re-wiring to the true lumen was attempted. Finally, the CTO lesion was recanalized without any complication and 1 year follow-up angiography had good result. ADR as preparation of IVUS-guided re-wiring might be one of the useful procedures for those complex CTO cases.

Percutaneous Coronary Intervention in Chronic Total Occlusion

Percutaneous coronary intervention in chronic total occlusion is a rapidly evolving area, being considered the last frontier of interventional cardiology. In recent years, the development of new techniques and equipment, as well as the training of specialized personnel, increased their success rates, making it the most predictable procedure available. Although the number of randomized and controlled studies is still limited, results from large multicentered registries allow us to safely offer this intervention to patients, as another treatment option along with the optimized drug treatment and myocardial revascularization surgery. This review summarizes the last and most relevant publications in the subject in order to provide an overall view of the field’s current status.