Subintimal dissection/reentry strategies in coronary chronic total occlusion interventions

PET evaluation of myocardial perfusion function after percutaneous coronary intervention in patients with chronic total occlusion: a systematic review and meta-analysis

Objective. The benefit of percutaneous coronary intervention (PCI) in chronic complete coronary artery occlusion (CTO) remains controversial. PCI is currently indicated only for symptom and myocardial ischemia abolition, but large chronically occluded vessels with extensive afferent myocardial territories may benefit most from this procedure. The noninvasive evaluation of myocardial perfusion is critical before and after revascularization, and positron emission tomography (PET) can determine absolute myocardial perfusion. Here, we aimed to explore and compare myocardial perfusion in CTO territories and their remote associated areas before and after PCI. Design. We searched for relevant articles published before November 28, 2022, in the Cochrane Library and PubMed. We calculated 95% confidence intervals (CIs) and standardized mean differences (SMDs) for parameters related to myocardial perfusion in CTO territories and remote areas in CTO patients before and after PCI. Results. We included five studies published between 2017 and 2022, with a total of 592 patients. Stress myocardial blood flow (MBF) was increased in CTO territories after PCI when compared to pre-PCI (mean difference [MD]: 1.70, 95% confidence interval [CI] 1.33-2.08, p < 0.001). Coronary flow reserve (CFR) in CTO regions was also higher after PCI (MD 1.37,95% [CI]1.13-1.61, p < 0.001). Stress MBF in remote regions was also increased after PCI (MD 0.27,95% [CI]0.99 ∼ 0.45, p = 0.004), as was CFR in remote regions (MD 0.32,95% [CI] 0.14-0.5, p = 0.001). Conclusions. According to our pooled analysis of current literature, there was an increase in stress MBF and CFR in both CTOs and remote regions after PCI, suggesting that patients with CTO have widespread recovery of blood perfusion after the procedure. These results provide evidence that patients with CTO arteries and high ischemic burdens would indeed benefit from CTO-PCI. Future research on the correlation of ischemia burden reduction with hard clinical endpoints would contribute to a clearer demarcation of the role of CTO PCI with prognostic potential.

The limited antegrade subintimal tracking technique to retrieve a trapped rotablator burr: a case report

Background

Burr entrapment is a rare, but potentially serious complication of rotablation. This report describes the percutaneous options available for Rota burr retrieval.

Case summary

A 62-year-old Caucasian man with stable angina presented for percutaneous coronary intervention. Attempted rotablation with a 1.75 mm burr resulted in Rota burr entrapment, in the heavily calcified proximal right coronary artery. A chronic total occlusion angioplasty technique (limited antegrade subintimal tracking) was successfully used to remove the trapped Rota burr, by enabling subintimal dilatation to externally crush plaque and dislodge the burr. The angioplasty procedure was then completed using the wire that had a short subintimal passage, before re-entering the true lumen.

Discussion

The mechanism for Rota burr entrapment, in this case, was initiating rotablation on the heavily calcified lesion and not more proximal to allow a pecking motion. The learning points are (i) to start the rotablator several millimetres proximal to the actual lesion, and (ii) if unable to wire alongside a trapped Rota burr in the true lumen, then subintimal crossing and balloon dilatation in the subintimal space may work to dislodge the burr.

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

Background

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

Case summary

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

Discussion

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

Use of the Carlino Technique in Chronic Total Occlusion Percutaneous Coronary Intervention

We examined the outcomes of the Carlino technique in chronic total occlusion (CTO) percutaneous coronary interventions (PCIs). We analyzed the baseline clinical and angiographic characteristics and outcomes of 128 CTO PCIs that included the Carlino technique at 22 US and no-US centers between 2016 and 2023. The Carlino technique was used in 128 (2.8%) of 4,508 cases that used anterograde dissection and reentry (78.9%) or the retrograde approach (21.1%) during the study period, and it increased steadily over time (from 0.0% in 2016 to 8.3% in 2023). The mean patient age was 65.6 ± 9.7 years, and 88.7% of the patients were men with high prevalence of hypertension (89.1%) and dyslipidemia (80.2%). The Carlino technique was more commonly used in cases with moderate to severe calcification (77.2% vs 55.5%, p <0.001) with higher J-CTO (3.3 ± 0.9 vs 3.0 ± 1.1, p = 0.007), Prospective Global Registry for the Study of Chronic Total Occlusion Intervention (PROGRESS-CTO) (1.7 ± 1.0 vs 1.4 ± 1.0, p = 0.001), PROGRESS-CTO Mortality (2.6 ± 0.9 vs 2.0 ± 0.9, p = 0.013) and PROGRESS-CTO Perforation (3.7 ± 1.1 vs 3.5 ± 1.0, p = 0.029) scores. Carlino cases had longer procedure and fluoroscopy time, and higher contrast volume and radiation dose. Carlino cases had lower technical (65.6% vs 78.5%, p <0.001) and procedural (63.3% vs 76.3%, p <0.001) success, similar major adverse cardiac events (6.2% vs 3.2%, p = 0.101) and higher incidence of pericardiocentesis (3.9% vs 1.3%, p = 0.042), perforation (18.0% vs 8.9%, p = 0.001) and contrast-induced acute kidney injury (2.3% vs 0.4%, p = 0.012). The Carlino technique was associated with higher procedural success when used for retrograde crossing (81.5% vs 58.4%, p = 0.047). The Carlino technique is increasingly being used in CTO PCI especially for higher complexity lesions.

Wire-based antegrade dissection re-entry technique for coronary chronic total occlusions percutaneous revascularization: Experience from the ERCTO Registry

BACKGROUND

The recent development and widespread adoption of antegrade dissection re-entry (ADR) techniques have been underlined as one of the antegrade strategies in all worldwide CTO consensus documents. However, historical wire-based ADR experience has suffered from disappointing long-term outcomes.

AIMS

Compare technical success, procedural success, and long-term outcome of patients who underwent wire-based ADR technique versus antegrade wiring (AW).

METHODS

One thousand seven hundred and ten patients, from the prospective European Registry of Chronic Total Occlusions (ERCTO), underwent 1806 CTO procedures between January 2018 and December 2021, at 13 high-volume ADR centers. Among all 1806 lesions attempted by the antegrade approach, 72% were approached with AW techniques and 28% with wire-based ADR techniques.

RESULTS

Technical and procedural success rates were lower in wire-based ADR than in AW (90.3% vs. 96.4%, p < 0.001; 87.7% vs. 95.4%, p < 0.001, respectively); however, wire-based ADR was used successfully more often in complex lesions as compared to AW (p = 0.017). Wire-based ADR was used in most cases (85%) after failure of AW or retrograde procedures. At a mean clinical follow-up of 21 ± 15 months, major adverse cardiac and cerebrovascular events (MACCEs) did not differ between AW and wire-based ADR (12% vs. 15.1%, p = 0.106); both AW and wire-based ADR procedures were associated with significant symptom improvements.

CONCLUSIONS

As compared to AW, wire-based ADR is a reliable and effective strategy successfully used in more complex lesions and often after the failure of other techniques. At long-term follow-up, patient's MACCEs and symptoms improvement were similar in both antegrade techniques.

Balloon-assisted subintimal entry (BASE) in chronic total occlusion percutaneous coronary interventions

BACKGROUND

There is limited data on the use of the balloon-assisted subintimal entry (BASE) technique in chronic total occlusion (CTO) percutaneous coronary intervention (PCI).

METHODS

We analyzed the baseline clinical and angiographic characteristics and outcomes of 155 CTO PCIs that utilized the BASE technique at 31 US and non-US centers between 2016 and 2023.

RESULTS

The BASE technique was used in 155 (7.9%) of 1968 antegrade dissection and re-entry (ADR) cases performed during the study period. The mean age was 66 ± 10 years, 88.9% of the patients were men, and the prevalence of diabetes (44.6%), hypertension (90.5%), and dyslipidemia (88.7%) was high. Compared with 1813 ADR cases that did not use BASE, the target vessel of the BASE cases was more commonly the RCA and less commonly the LAD. Lesions requiring BASE had longer occlusion length (42 ± 23 vs. 37 ± 23 mm, p = 0.011), higher Japanese CTO (J-CTO) (3.4 ± 1.0 vs. 3.0 ± 1.1, p < 0.001) and PROGRESS-CTO (Prospective Global Registry for the Study of Chronic Total Occlusion Intervention chronic total occlusion) (1.8 ± 1.0 vs. 1.5 ± 1.0, p = 0.008) scores, and were more likely to have proximal cap ambiguity, side branch at the proximal cap, blunt/no stump, moderate to severe calcification, and proximal tortuosity. Technical (71.6% vs. 75.5%, p = 0.334) and procedural success (71.6% vs. 72.8%, p = 0.821), as well as major adverse cardiac events (MACE) (1.3% vs. 4.1%, p = 0.124), were similar in ADR cases that used BASE and those that did not.

CONCLUSIONS

The BASE technique is used in CTOs with longer occlusion length, higher J-CTO score, and more complex angiographic characteristics, and is associated with moderate success but also low MACE.

Trends and Inhospital Outcomes of Intravascular Imaging on Single-Vessel Coronary Chronic Total Occlusion Treated With Percutaneous Coronary Intervention

Intravascular imaging (IVI), including intravascular ultrasound (IVUS) and optical coherence tomography (OCT), improves outcomes of percutaneous coronary intervention (PCI) for chronic total occlusions (CTOs). We sought to quantify temporal trends in the uptake of IVI for CTO-PCI in the United States. We identified adults who underwent single-vessel PCI for CTO between 2008 and 2020. We quantified yearly trends in the number of IVUS-guided and OCT-guided single-vessel CTO-PCIs by Cochran-Armitage and linear regression tests. We also examined the rates of inhospital mortality and other prespecified inhospital outcomes in patients who underwent CTO-PCIs with and without IVI, using logistic regression. Our study included a total of 151,998 PCIs on single-vessel CTOs, with the absolute number of CTO-PCIs decreasing from 12,345 in 2008 to 8,525 in 2020 (p trend <0.001). IVUS use has increased dramatically from 6% in 2008 to 18% in 2020 for single-vessel CTO-PCIs (p trend <0.001). Rates of OCT use have increased as well, from 0% in 2008 to 7% in 2020 (p trend <0.001). There was no difference in inhospital mortality between patients who underwent CTO-PCI with and without IVI (p logistic = 0.60). In the largest national analysis of single-vessel CTO-PCI trends to date, we found that the use of IVUS has increased substantially accompanied by a similar but lesser increase in the use of OCT. There were no differences in rates of inhospital mortality between patients who underwent single-vessel CTO-PCIs with and without IVI.

Subintimal recanalization for non-acute occlusion of intracranial vertebral artery in an emergency endovascular procedure: A case report

BACKGROUND

Endovascular recanalization of non-acute intracranial artery occlusion is technically difficult, particularly when the microwire enters the subintima. Although the subintimal tracking and re-entry technique has been well established in the endovascular treatment of coronary artery occlusion, there is limited experience with its use in intracranial occlusion due to anatomical variations and a lack of dedicated devices.

CASE SUMMARY

A 74-year-old man was admitted to the hospital two days after experiencing acute weakness in both lower extremities, poor speech, and dizziness. After admission, imaging revealed acute ischemic stroke and non-acute occlusion of bilateral intracranial vertebral arteries (ICVAs). On the fourth day of admission, the patient's condition deteriorated and an emergency endovascular recanalization of the left ICVA was performed. During this procedure, a microwire was advanced in the subintima of the vessel wall and successfully reentered the distal true lumen. Two stents were implanted in the subintima. The patient's Modified Rankin Scale was 1 at three months postoperatively.

CONCLUSION

We present a technical case of subintimal recanalization for non-acute ICVA occlusion in an emergency endovascular procedure. However, we emphasize the necessity for caution when applying the subintimal tracking approach in intracranial occlusion due to the significant dangers involved.

Changes in absolute flow, myocardial resistance and FFR after chronic total occlusion percutaneous coronary intervention

BACKGROUND

Randomised studies of percutaneous coronary intervention (PCI) in patients with chronic total occlusion (CTO) have shown inconsistent outcomes, suggesting incomplete understanding of this cohort and their coronary physiology. To address this shortcoming, we designed a prospective observational study to measure the recovery of absolute coronary blood flow following successful CTO PCI Aims: We sought to identify patient and procedural characteristics associated with a favourable physiological outcome after CTO PCI.

METHODS

Consecutive patients with a CTO subtending viable myocardium underwent PCI utilising contemporary techniques and the hybrid algorithm. Immediately after PCI, and at 3-month follow-up, physiological measurements were performed utilising continuous thermodilution.

RESULTS

A total of 81 patients were included with a mean age of 63.6±8.9 years, and 66 (81.5%) were male. Physiological measurements of absolute coronary blood flow in the CTO vessel increased by 30% (p<0.001) and microvascular resistance reduced by 16% (p<0.001) from immediately post-CTO PCI to follow-up assessment. Fractional flow reserve increased by 0.02 (p=0.015) in the same period. Prior coronary artery bypass graft (CABG) and a higher estimated glomerular filtration rate (eGFR) were associated with a larger change in absolute flow. An extraplaque strategy was associated with a smaller change in absolute flow.

CONCLUSIONS

Post-CTO PCI, there is a continued augmentation in absolute coronary blood flow and reduction in microvascular resistance from baseline to follow-up at 3 months. Prior CABG and a higher baseline eGFR were predictors of a larger change in absolute coronary flow, whilst an extraplaque final wire path strategy predicted a smaller change. Lastly, the patient characteristics and comorbidities had a larger influence than procedural factors on the observed change in absolute flow.

Acute coronary complications in chronic total occlusion interventions

Chronic total occlusion (CTO) interventions are among the most complex procedures within the panorama of percutaneous coronary intervention (PCI). Awareness of potential complications, adequate procedural planning in order to avoid them, and prompt recognition and management should any occur are at the cornerstone of a successful CTO programme. Complications can be acute or late after the procedure and can be cardiac or non-cardiac. Acute cardiac complications can occur directly at the coronary artery level or can have other strictly non-coronary manifestations, such as hypotension, myocardial infarction, arrhythmias, or tamponade. In this review, we focus on acute coronary complications of CTO PCI, in particular their causes, prevention, and management strategies.

Role of the retrograde Carlino technique for chronic total occlusion percutaneous coronary intervention

BACKGROUND

There is scarce data on the outcomes of the Carlino technique for chronic total occlusion (CTO) percutaneous coronary intervention (PCI). We aimed to investigate the indications and outcomes of the Carlino technique as performed in the context of the retrograde approach.

METHODS

We pooled CTO PCI cases where a retrograde Carlino technique was performed from high-volume operators at four centers. The Carlino technique was characterized according to its indication (achieving plaque/cap modification, clarifying microcatheter location within the vessel, resolving distal cap ambiguity) and was considered successful when it led to the desired outcome.

RESULTS

A total of 43 patients were included. Occlusion complexity was very high (mean J-CTO score 3.3 ± 0.8). The two most common indications were understanding the anatomy of the occlusion and clarifying gear location (37.2%) and impenetrable distal cap (34.9%). The Carlino technique was successful in 88.4% of cases. Overall technical and procedural success was 86.0%. The most common successful crossing technique was reverse controlled antegrade and retrograde subintimal tracking (70.3%). No complications were attributed to the Carlino technique.

CONCLUSIONS

We observed a high success rate of the retrograde Carlino technique, as well as overall technical and procedural success rates. No Carlino technique-related complications were observed. Additional data from larger registries are warranted to further confirm the safety and efficacy of this technique.

Development and validation of a scoring system for predicting clinical coronary artery perforation during percutaneous coronary intervention of chronic total occlusions: the PROGRESS-CTO perforation score

BACKGROUND

Coronary artery perforation is a feared complication of chronic total occlusion (CTO) percutaneous coronary intervention (PCI) and often leads to serious adverse clinical events.

AIMS

We sought to develop a risk score to predict clinical coronary artery perforation in patients undergoing CTO PCI.

METHODS

We analysed clinical and angiographic parameters from 9,618 CTO PCIs in the Prospective Global Registry for the Study of Chronic Total Occlusion Intervention (PROGRESS-CTO). Logistic regression prediction modelling was used to identify variables independently associated with clinical perforation, and the model was internally validated with bootstrapping. Clinical coronary artery perforation was defined as any perforation requiring treatment.

RESULTS

The incidence of clinical coronary perforation was 3.8% (n=367). Five factors were independently associated with perforation and were included in the score: patient age ≥65 years +1 point (odds ratio [OR] 1.79, 95% confidence interval [CI]: 1.37-2.33), moderate/severe calcification +1 point (OR 1.85, 95% CI: 1.41-2.42), blunt/no stump +1 point (OR 1.45, 95% CI: 1.10-1.92), use of antegrade dissection and re-entry +1 point (OR 2.43, 95% CI: 1.61-3.69), and use of the retrograde approach +2 points (OR 4.02, 95% CI: 2.95-5.46). The resulting score showed acceptable performance on receiver operating characteristic (ROC) curve (area under the curve [AUC]: 0.741, 95% CI: 0.712-0.773). The Hosmer-Lemeshow test indicated a good fit (p=0.991), and internal validation with bootstrapping demonstrated good agreement with the model with observed AUC: 0.736 (95% bias-corrected CI: 0.706-0.767).

CONCLUSIONS

The PROGRESS-CTO perforation score may be a useful tool for predicting clinical coronary perforation during CTO PCI.

Coronary intravascular brachytherapy for in-stent restenosis: A review of the contemporary literature

Intracoronary stent restenosis (ISR) is a clinically relevant challenge in the modern era. Heterogeneity in patient- and lesion-specific factors can further compound this clinical challenge. Coronary intravascular brachytherapy (IVBT) was the standard therapeutic approach for ISR prior to the advent of drug-eluting stents (DES). Despite prospective data describing the superiority of DES over IVBT for treating de novo ISR, IVBT remains a treatment option for patients with complex disease. The purpose of this review is to evaluate the historical and contemporary literature surrounding IVBT in order to elucidate its role in modern cardiac care and to describe opportunities for future investigations to improve patient selection. Herein, we provide a review of the contemporary literature describing IVBT as a safe and effective treatment option for patients with recurrent, refractory ISR after multilayer DES and no good surgical or mechanical option. Combination therapy with emerging technologies such as DCBs may further increase efficacy.

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

Background

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

Case summary

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

Discussion

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

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.

Complications during chronic total occlusion percutaneous coronary intervention: a sign- and symptom-based approach to early diagnosis and treatment

Coronary chronic total occlusions (CTO) are frequently found in patients undergoing coronary angiography. Despite their high prevalence and indication for revascularization in a relevant proportion of cases, CTO recanalization is attempted only in a minority of cases. This is due to higher risk of procedural complications compared to non-CTO interventions and because the CTO-PCIs are the most complex procedures in interventional cardiology. In particular, the perceived higher risk of complications during CTO intervention might discourage new operators from engaging in this challenging field. The aim of this work is to review the potential complications of CTO percutaneous coronary intervention, and to provide an algorithmic, sign- and symptom-based approach to facilitate early recognition and effective management.

Subintimal shift at the bifurcation: A cause of side branch occlusion in chronic total occlusion intervention

Bifurcation lesions are frequently found in chronic total occlusion (CTO) percutaneous coronary intervention and are associated with lower procedural success and higher rates of complications, including side branch loss. In this report, we describe a poorly understood mechanism for side branch loss in CTO PCI: subintimal shift. This involves the extension of a dissection plane caused by subintimal (extraplaque) crossing in the main branch at the level of the side branch ostium, causing exclusion of the latter upon vessel preparation or stent placement. Subintimal shift (as compared to carina shift in non-CTO bifurcation intervention) appears to be under-recognized, and CTO operators should be aware that, from a technical standpoint, ballooning of the side branch is unlikely to restore and maintain flow, and a two-stent strategy is indicated to preserve the bifurcation.

Current challenges and prevention strategies for chronic total occlusion (CTO) complications

Introduction: Percutaneous coronary intervention (PCI) of chronic total occlusion (CTO) can be challenging, but high success rates (85-90%) are currently achieved at experienced centers with approximately 3% risk for a major periprocedural complication.Areas covered: CTO PCI complications can be categorized according to location such as cardiac and non-cardiac (vascular access complications, thromboembolic complications, contrast-related and radiation injury) complications. Cardiac complications are further subdivided into coronary (acute closure, perforation, and equipment loss or entrapment) and non-coronary (hypotension, myocardial infarction, tamponade, arrhythmias).Expert opinion: In this article, we review strategies to prevent and treat CTO PCI complications. Careful monitoring throughout the case enables prevention and early detection of a complication. If a complication occurs, rapid implementation of treatment using an algorithmic approach can minimize its adverse impact.

Clinical Outcomes in Chronic Total Occlusion Revascularization Versus No Chronic Total Occlusion Revascularization: Variability by Target Vessel

We aimed to investigate the impact of target vessel on clinical outcomes in chronic total occlusion (CTO) revascularization versus no CTO revascularization. This multicenter, retrospective, cohort study involves patients with ≥1 CTO. After classification based on different CTO target vessels or multiple CTOs, patients were further categorized as the CTO revascularization group and the no CTO revascularization group based on treatment received. The primary outcome was a composite of death, myocardial infarction, stroke, repeated revascularization, and hospital admission due to ischemic symptoms. From August 2016 to August 2017, 1712 eligible patients were consecutively enrolled. Chronic total occlusion revascularization was associated with lower risk of 1-year major adverse cardiovascular and cerebrovascular events (MACCEs; adjusted hazard ratio [HR]: 0.36; 95% CI: 0.20-0.67; P = .001) compared with no CTO revascularization in left anterior descending (LAD) CTO patients. The benefit of CTO revascularization was not evident among those with left circumflex (LCX; adjusted HR: 0.51; 95% CI: 0.23-1.10; P = .087), right coronary artery (RCA; adjusted HR: 1.17; 95% CI: 0.59-2.33; P = .648), and multiple CTOs (adjusted HR: 1.00; 95% CI: 0.41-2.44; P = .994). Revascularization for LAD CTO, but not LCX, RCA, or multiple CTOs, was associated with lower risk of 1-year MACCEs compared with no CTO revascularization.

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

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

Knuckle wire technique in percutaneous coronary intervention of chronic total occlusion: Knuckle wire technique

In percutaneous coronary intervention, the knuckle wire technique is one of the approaches to cross the long and ambiguous course of the occluded segment. However, this technique is generally used as a last alternative, when all other techniques fail. Although knuckle wiring expedites chronic total occlusion crossing, it can also complicate the percutaneous coronary intervention strategy irreversibly. Therefore, understanding the various aspects of the knuckle wire technique is a prerequisite in a chronic total occlusion setting. The authors herein intend to describe in detail the knuckle wire technique and its safe and effective approach in various chronic total occlusion wiring strategies, while befitting to the scope of a mainstream interventionist.

Association of Acute Procedural Results With Long-Term Outcomes After CTO PCI

OBJECTIVES

The aim of this study was to determine the association of procedural outcomes with long-term mortality and myocardial infarction (MI) after chronic total occlusion (CTO) percutaneous coronary intervention (PCI).

BACKGROUND

The association between acute procedural results and subsequent outcomes has received limited study.

METHODS

Between January 2010 and December 2013, a total of 2,659 CTO PCI patients were consecutively enrolled. Procedural results were categorized into 3 groups: 1) optimal recanalization, with reperfusion of the occluded vessel and side branches (if any) with TIMI (Thrombolysis In Myocardial Infarction) flow grade 3; 2) suboptimal recanalization, meeting any of the following criteria: persistence of significant side branch occlusion, final TIMI flow grade 1 or 2, or residual percentage diameter stenosis >30%; and 3) procedural failure (i.e., failure to cross a lesion with a balloon angioplasty catheter). The primary outcome was the 5-year composite endpoint of cardiac death and MI.

RESULTS

Overall, optimal recanalization was achieved in 1,562 patients (58.7%), suboptimal recanalization was achieved in 399 patients (15.0%), and recanalization failed in 698 patients (26.3%). The 5-year incidence of the primary outcome was significantly higher in the suboptimal recanalization group compared with the optimal recanalization and the failure groups (10.1% vs. 6.5% vs. 6.3%; p = 0.046), which was driven mainly by higher risk for MI. In subgroup analysis, significant side branch occlusion was associated with numerically higher risk for 5-year MI (hazard ratio: 1.55; 95% confidence interval: 0.99 to 2.43; p = 0.054).

CONCLUSIONS

In this large cohort of CTO PCI patients, suboptimal recanalization was associated with significantly higher long-term incidence of cardiac death and MI compared with optimal recanalization or procedural failure.

Complications of chronic total occlusion percutaneous coronary intervention

Chronic total occlusion percutaneous coronary interventions can be highly complex and are associated with an increased risk of complications, such as perforation, acute vessel closure (which can lead to rapid haemodynamic compromise if it involves the donor vessel), and equipment loss or entrapment. Awareness of the potential complications and meticulous attention to equipment position and patient monitoring can help minimise the risk of complications and allow prompt treatment should they occur.

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.

Outcomes after percutaneous coronary intervention and comparison among scoring systems in predicting procedural success in elderly patients (≥ 75 years) with chronic total occlusion

BACKGROUND

Evidence-based data on percutaneous coronary intervention in elderly patients with chronic total occlusion (CTO) and comparison among different scoring systems have not been well established.

PATIENTS AND METHODS

A total of 246 consecutive patients were stratified into two groups according to the age: elderly group (age≥ 75 years, n = 68) and nonelderly group (age < 75 years, n = 178). Clinical and angiographic characteristics including the Synergy Between PCI With TAXUS and Cardiac Surgery score, in-hospital major adverse cardiac events, procedural success rates, and predictive capacity of four scoring systems [J-CTO, Prospective Global Registry for the Study of Chronic Total Occlusion Intervention (PROGRESS CTO), clinical and lesion-related (CL), and ostial location, Rentrop grade < 2, age ≥ 75 years (ORA) scores] were examined.

RESULTS

Triple-vessel disease and the Synergy Between PCI With TAXUS and Cardiac Surgery score in the elderly group were significantly higher than those in the nonelderly group (73.53 vs. 53.93%, P = 0.005; 31.39 ± 7.68 vs. 27.85 ± 7.16, P = 0.001, respectively). The in-hospital major adverse cardiac event rates, vascular access complication rates, and major bleeding rates were similar between the elderly and the nonelderly group (2.94 vs. 2.25%, P = 0.669; 1.47 vs. 0.56%, P = 0.477; 2.94 vs. 1.12%, P = 0.306, respectively). By contrast, the procedural success rate was statistically lower in the elderly group than that in the nonelderly group (73.53 vs. 84.83%, P = 0.040). All the four scoring systems showed a moderate predictive capacity [area under the curve (AUC) for J-CTO score: 0.806, P < 0.0001; AUC for PROGRESS CTO score: 0.727, P < 0.0001; AUC for CL score: 0.800, P < 0.0001; AUC for ORA score: 0.672, P < 0.0001, respectively]. Compared with the ORA score, the J-CTO score, and the CL score showed a significant advantage in predicting procedural success among overall patients (ΔAUC = 0.134, P = 0.0122; ΔAUC = 0.128, P = 0.0233, respectively).

CONCLUSION

Despite the lower procedural success rate, percutaneous coronary intervention in elderly patients with CTO is feasible and safe. J-CTO, PROGRESS, ORA, and CL scoring systems have moderate discriminatory capacity.

The Cupidon's Strike Technique: How to Never Miss a Rendezvous While Going on SAFARI

One of the difficulties of the subintimal arterial flossing with antegrade-retrograde intervention technique (SAFARI) technique is to properly achieve a rendezvous between both antegrade and retrograde accesses. We propose a new technique to overcome this difficulty. It consists of directly percutaneously puncturing 2 loop snares, placed via each access, which are then both used to snare an externally introduced guidewire introduced through the needle. The snares are then moved en bloc, bringing both snares and the wire into the same channel.

Procedural outcomes of chronic total occlusion percutaneous coronary intervention in patients with dissection and reentry versus wire escalation techniques: a meta-analysis

BACKGROUND

The procedural safety of dissection and reentry (DR) techniques in chronic total occlusion (CTO) percutaneous coronary intervention (PCI) remains controversial, when compared with conventional wire escalation (WE) techniques. The meta-analysis was performed to evaluate the impact of DR techniques vs. WE techniques on periprocedural outcomes in patients with CTO undergoing PCI.

METHODS

Studies were searched in electronic database from inception to December 2018. Results were pooled using random effects model and fixed effects model.

RESULTS

The pooled analyses revealed that DR techniques increased risks of periprocedural complications in patients with CTO PCI, including higher coronary perforation rate [risk ratio (RR) = 2.10, 95% confidence interval (CI) 1.24-3.55], periprocedural myocardial infarction (RR = 1.85, 95% CI 1.23-2.78), branch occlusion (RR = 2.69; 95% CI 1.92-3.77) and coronary hematoma (RR = 3.06; 95% CI 2.45-3.82) detected by intravascular ultrasound, when compared to those with WE techniques. However, DR techniques were more applied in patients with higher complexity CTO lesions, which was evidenced by higher J-CTO score [standard mean differences (SMD) = 0.71, 95% CI 0.51-0.91] and longer fluoroscopy time (SMD = 0.93, 95% CI 0.70-1.16), that may explain the higher complications rates in the DR techniques group as compared with WE techniques.

CONCLUSION

The present meta-analysis suggests that the DR technique is relatively frequently used during contemporary CTO PCI, especially for challenging more complex CTO lesions. However, it is associated with higher, yet acceptable, rates of periprocedural adverse events as compared with a conventional WE strategy. Further refinement of DR techniques and evidence from large RCTs is needed to define the optimal role of DR in hybrid CTO PCI.

Antegrade Chronic Total Occlusion Strategies: A Technical Focus for 2020

Chronic total occlusions (CTOs) are common in patients with ischaemic heart disease. In many countries, patients with CTOs are underserved by percutaneous coronary intervention (PCI). One of the barriers to CTO PCI is the technical challenges of these procedures. Improvements in technique and dedicated devices for CTO PCI, combined with advances in procedural strategy, have resulted in a dramatic increase in procedural success and outcomes. Antegrade wiring (AW) is the preferred initial strategy in short CTOs, where the proximal cap and course of the vessel is understood. For many longer, more complex occlusions, AW has a low probability of success. Dissection and re-entry techniques allow longer CTOs and those with ambiguous anatomy to be crossed safely and efficiently, and CTO operators must also be familiar with these strategies. The CrossBoss and Stingray system is currently the primary targeted re-entry device used during antegrade dissection and re-entry (ADR), and there continues to be an evolution in its use to increase procedural efficiency. In contrast to older ADR techniques, targeted re-entry allows preservation of important side-branches, and there is no difference in outcomes compared to intraplaque stenting.

Stuck Between a Rock and a Hard Place: Management of an Entrapped Rotablator Burr

Burr entrapment remains a serious complication of rotational atherectomy. This report describes an advanced technique for the management of entrapped atherectomy burrs. Commonly strategies were unsuccessful. A chronic total occlusion angioplasty technique was used successfully: the subintimal dilation and "external crushing" plaque modification technique. (Level of Difficulty: Advanced.).

Outcomes with retrograde versus antegrade chronic total occlusion revascularization

OBJECTIVES

The aim of the study was to evaluate the outcomes of retrograde versus antegrade approach in chronic total occlusion (CTO) percutaneous coronary intervention (PCI).

BACKGROUND

The retrograde approach has increased the success rate of CTO PCI but has been associated with a higher risk for complications.

METHODS

We conducted a meta-analysis of studies published between 2000 and August 2019 comparing the in-hospital and long-term outcomes with retrograde versus antegrade CTO PCI.

RESULTS

Twelve observational studies (10,240 patients) met our inclusion criteria (retrograde approach 2,789 patients, antegrade approach 7,451 patients). Lesions treated with the retrograde approach had higher J-CTO score (2.8 vs. 1.9, p < .001). Retrograde CTO PCI was associated with a lower success rate (80.9% vs. 87.4%, p < .001). Both approaches had similar in-hospital mortality, urgent revascularization, and cerebrovascular events. Retrograde CTO PCI was associated with higher risk of in-hospital myocardial infarction (MI; odds ratio [OR] 2.37, 95% confidence intervals [CI] 1.7, 3.32, p < .001), urgent pericardiocentesis (OR 2.53, 95% CI 1.41-4.51, p = .002), and contrast-induced nephropathy (OR 2.12, 95% CI 1.47-3.08; p < .001). During a mean follow-up of 48 ± 31 months retrograde crossing had similar mortality (OR 1.79, 95% CI 0.84-3.81, p = .13), but a higher incidence of MI (OR 2.07, 95% CI 1.1-3.88, p = .02), target vessel revascularization (OR 1.92, 95% CI 1.49-2.46, p < .001), and target lesion revascularization (OR 2.08, 95% CI 1.33-3.28, p = .001).

CONCLUSIONS

Compared with antegrade CTO PCI, retrograde CTO PCI is performed in more complex lesions and is associated with a higher risk for acute and long-term adverse events.

Animal chronic total occlusion models: A review of the current literature and future goals

Coronary chronic total occlusions (CTOs) are commonly found in patients undergoing coronary angiography and is associated with poorer prognosis than in those patients with other forms of stable coronary artery disease. As such, with an increasing appreciation of this clinical entity, there is a need to identify, firstly the pathophysiological process driving its formation, as well as new percutaneous strategies for revascularisation with long term durability and improved outcomes. An appropriate, reliable and reproducible animal model is vital for both of these objectives. We review the prevalence of spontaneous collaterals in different species, as well as review the current literature with respect to animal models of CTOs, and compare and contrast the advantages and disadvantages of these differing models. Whilst both extrinsic compression models and endoluminal procedures may create situations analogous to a CTO in a human, the ideal animal model of a CTO will include an occluded artery, functional collaterals and a viable myocardium. This would allow study of the process driving collateral formation and arteriogenesis as well as percutaneous intervention strategies for both acute and long term benefits.

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.

Long Chronic Total Occlusions: Revascularization Strategies

The treatment of chronic total occlusions (CTO) in patients with peripheral arterial disease (PAD) is a complex topic with multiple treatment techniques and treatment strategies. The interventionalist treating patients with PAD should have both a defined treatment algorithm and multiple techniques available for crossing these challenging lesions. This article will cover techniques for treating CTOs and provide an overview of current available evidence.

Clinical and angiographic outcomes of true vs. false lumen stenting of coronary chronic total occlusions: Insights from intravascular ultrasound

OBJECTIVES

The clinical implications of subintimal stenting (SS) of the recanalized chronic total occlusion (CTO) segment have not been characterized. We evaluated the in-hospital and the long-term clinical and angiographic outcomes of drug-eluting stents (DESs) deployed in true vs. false lumen of successfully recanalized CTO.

METHODS AND RESULTS

Two independent reviewers analyzed the intravascular ultrasound (IVUS) images of 173 successfully recanalized CTO lesions (157 patients), between August 2011 and October 2012. After successful guidewire (GW) crossing, lesions were classified according to IVUS evaluation into two groups: (1) true lumen (TL) stenting group and (2) SS group; and compared with regards to in-hospital and long-term clinical outcomes. In 154 lesions, DESs were deployed in the TL; and in 19 (11%) lesions, DESs were deployed in the subintimal space (95% confidence interval: 6.3-15.6%). False GW tracking in the SS group resulted in increased rates of IVUS-detected dissection flaps (84% vs. 42.6%, P ≤ 0.001), intramural hematoma (32 vs. 11%, P = 0.01), and minor perforations 6/19 (31.6% vs. 8.4%, P = 0.002). At 1-year follow-up, both groups had similar cumulative rates of binary restenosis and target lesion revascularization (P = 0.73 and P = 0.97, respectively). Six patients (4.6%, 6/129 patients) in the TL group and none in the subintimal group died at 1 year.

CONCLUSIONS

Acknowledging some limitations, our observations may suggest that, subintimal stent deployment in a recanalized CTO segments, using second generation DES and IVUS guidance, might have a comparable success rate and long-term angiographic and clinical outcomes as TL stenting.

Assessing the landscape of percutaneous coronary chronic total occlusion treatment in Belgium and Luxembourg: the Belgian Working Group on Chronic Total Occlusions (BWGCTO) registry

Background: Important developments in materials, devices, and techniques have improved outcomes of chronic total occlusion (CTO) percutaneous coronary intervention (PCI), and resulted in a growing interest in CTO-PCI. The Belgian Working Group on Chronic Total Occlusions (BWGCTO) working group aims to assess the evolution within the CTO-PCI landscape over the next years. Methods: From May 2016 onwards, patients undergoing CTO-PCI were included in the BWGCTO registry by 15 centres in Belgium and Luxemburg. Baseline, angiographic, and procedural data were collected. Here, we report on the one-year in-hospital outcomes. Results: Over the course of one year, 411 procedures in 388 patients were included with a mean age of 64 ± 11 years. The majority were male (81%). Relatively complex CTOs were treated (Japanese CTO score =2.2 ± 1.2) with a high procedure success rate (82%). Patient- and lesion-wise success rates were 83 and 85%, respectively. Major adverse in-hospital events were acceptably low (3.4%). Antegrade wire escalation technique was applied most frequently (82%). On the other hand, antegrade dissection and re-entry and retrograde strategies were more frequently applied in higher volume centres and successful for lesions with higher complexity. Conclusion: Satisfactory procedural outcomes and a low rate of adverse events were obtained in a complex CTO population, treated by operators with variable experience levels. Antegrade wire escalation was the preferred strategy, regardless of operator volume.

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).