The safety and feasibility of live-stream proctoring for CTO procedures.

OBJECTIVE: To assess the technical feasibility of a new method of educational training, based on audio-video (AV) communication between an interventional cardiologist and the cath lab staff members in one location and a remote expert proctor. METHODS: Overall, 9 patients underwent a percutaneous coronary intervention (PCI) targeting a chronic total occlusion (CTO) between June 2021 and January 2022 at a single Belgian center using the virtual proctoring approach. For this assessment, the strategic planning of the CTO PCI and all the decisions throughout the intervention were the responsibility of the proctor. The operator was guided via an AV link, by the proctor throughout the procedure. RESULTS: The operator performed each procedural step, guided by the remote proctor, who had continuous access to all relevant interventional details. No major adverse cardiac events (MACE) occurred during the index hospitalization or within 6 months follow-up. CONCLUSIONS: A new method of virtual proctoring based on live AV communication is feasible, even in the case of highly complex CTO PCI procedures. This strategy also appears safe and may provide the patient the benefit of incremental expertise. This approach is facilitated by advances in AV communication and allows physicians to share expertise irrespective of location. It could increase global interaction between colleagues and facilitate sharing of knowledge, which are both key aspects in the development of CTO PCI. This preliminary experience could serve as a basis for future large studies to study the potential role and benefits of virtual proctoring for complex CTO PCI procedures.

IRIDIA-AF, a large paroxysmal atrial fibrillation long-term electrocardiogram monitoring database.

Atrial fibrillation (AF) is the most common sustained heart arrhythmia in adults. Holter monitoring, a long-term 2-lead electrocardiogram (ECG), is a key tool available to cardiologists for AF diagnosis. Machine learning (ML) and deep learning (DL) models have shown great capacity to automatically detect AF in ECG and their use as medical decision support tool is growing. Training these models rely on a few open and annotated databases. We present a new Holter monitoring database from patients with paroxysmal AF with 167 records from 152 patients, acquired from an outpatient cardiology clinic from 2006 to 2017 in Belgium. AF episodes were manually annotated and reviewed by an expert cardiologist and a specialist cardiac nurse. Records last from 19 hours up to 95 hours, divided into 24-hour files. In total, it represents 24 million seconds of annotated Holter monitoring, sampled at 200 Hz. This dataset aims at expanding the available options for researchers and offers a valuable resource for advancing ML and DL use in the field of cardiac arrhythmia diagnosis.

Microcatheter-versus wire-based measurement of the fractional flow reserve.

BACKGROUND: Fractional flow reserve (FFR) guided-percutaneous interventions is nowadays the gold standard for optimal coronary artery revascularization. While multiple pressure guidewires have been validated, the use of microcatheter for FFR measurements is still a matter of debate. OBJECTIVE: The aim of this study was to investigate the crossing profile characteristics of the NAVVUS® microcatheter as compared with the COMETTM pressure wire. At the same time, we compared non-hyperaemic pressure ratio (NHPR) and FFR measurements of both systems. METHOD/MATERIALS: In this retrospective study, all angiographically intermediate coronary artery stenoses each month were assessed, using either the NAVVUS® or the COMETTM pressure system, to receive coronary artery physiology assessment with NHPR and FFR measurements. The crossing profile of both systems was compared regarding objective coronary artery lesion characteristics using quantitative coronary analysis evaluation. RESULTS: Over a period of 4.5 years, we evaluated 213 coronary artery stenoses using one of the two coronary tools. We found a 9.2% crossing profile failure rate using the microcatheter, compared to 0.7% in the pressure wire group (p < .001). The crossing failure was significantly correlated with the presence of coronary artery calcifications and angulation (p = .042, p = .049, respectively). FFR values were comparable be- tween the two groups and were significantly lower in the presence of coronary calcifications and proportional to the degree of stenosis (p = .036, p = .010). Pressure drift was comparable. CONCLUSION: Our observations are in line with other studies reporting the poor crossing profile of the NAVVUS® microcatheter. NHPR and FFR measures of both systems were well correlated.

The Interplay between Atherosclerosis and Cancer: Breast Cancer Cells Increase the Expression of Endothelial Cell Adhesion Markers.

Cardiovascular diseases are the leading causes of death worldwide, closely followed by cancer. To investigate the impact of breast cancer cell lines (SKBR3, MCF-7, and MDA-MB-231) on endothelial cell adhesion, a blended medium containing 30% breast-cancer-conditioned medium was prepared. This medium was then exposed to human umbilical vein endothelial cells (HUVECs) and monocytes (THP-1) for 48 h. Homemade oxidized low-density lipoproteins (oxLDL) were optionally added to the blended medium. Immunofluorescence was performed to assess the expression of E-selectin, connexin-43, and ICAM-1 on HUVECs, as well as LOX-1, CD36, and CD162 on THP-1. Additionally, unoxidized LDL was exposed to the three breast cancer cell lines for 48 h, and the formation of oxLDL was quantified. Our results revealed an upregulation of all six adhesion markers involved in the initiation of atherosclerosis when HUVECs and THP-1 were exposed to the breast-cancer-conditioned medium. Furthermore, this expression was further increased by exposure to oxLDL. We also observed a significant elevation in oxLDL levels when LDL was exposed to breast cancer cells. In conclusion, our findings successfully demonstrate an increased LDL oxidation in the presence of breast cancer cells, accompanied by an augmented expression of receptors involved in atherosclerosis initiation. These findings shed new light on the clinically observed interplay between atherosclerosis and cancer.

Bioresorbable Magnesium-Based Stent: Real-World Clinical Experience and Feasibility of Follow-Up by Coronary Computed Tomography: A New Window to Look at New Scaffolds.

(1) Background: The diagnostic accuracy of coronary computed tomography angiography (CCTA) for coronary artery disease (CAD) has greatly improved so CCTA represents a transition in the care of patients suffering from CAD. Magnesium-based bioresorbable stents (Mg-BRS) secure acute percutaneous coronary intervention (PCI) results without leaving, in the long term, a metallic caging effect. The purpose of this real-world study was to assess clinical and CCTA medium- and long-term follow-up of all our patients with implanted Mg-BRS. (2) Methods: The patency of 52 Mg-BRS implanted in 44 patients with de novo lesions (24 of which had acute coronary syndrome (ACS)) was evaluated by CCTA and compared to quantitative coronary angiography (QCA) post-implantation. (3) Results: ten events including four deaths occurred during a median follow-up of 48 months. CCTA was interpretable and in-stent measurements were successful at follow-up without being hindered by the stent strut's "blooming effect". Minimal in-stent diameters on CCTA were found to be 1.03 ± 0.60 mm smaller than the expected diameter after post-dilation on implantation (p < 0.05), a difference not found in comparing CCTA and QCA. (4) Conclusions: CCTA follow-up of implanted Mg-BRS is fully interpretable and we confirm the long-term Mg-BRS safety profile.

High Fidelity Pressure Wires Provide Accurate Validation of Non-Invasive Central Blood Pressure and Pulse Wave Velocity Measurements.

Central blood pressure (cBP) is known to be a better predictor of the damage caused by hypertension in comparison with peripheral blood pressure. During cardiac catheterization, we measured cBP in the ascending aorta with a fluid-filled guiding catheter (FF) in 75 patients and with a high-fidelity micromanometer tipped wire (FFR) in 20 patients. The wire was withdrawn into the brachial artery and aorto-brachial pulse wave velocity (abPWV) was calculated from the length of the pullback and the time delay between the ascending aorta and the brachial artery pulse waves by gating to the R-wave of the ECG for both measurements. In 23 patients, a cuff was inflated around the calf and an aorta-tibial pulse wave velocity (atPWV) was calculated from the distance between the cuff around the leg and the axillary notch and the time delay between the ascending aorta and the tibial pulse waves. Brachial BP was measured non-invasively and cBP was estimated using a new suprasystolic oscillometric technology. The mean differences between invasively measured cBP by FFR and non-invasive estimation were -0.4 ± 5.7 mmHg and by FF 5.4 ± 9.4 mmHg in 52 patients. Diastolic and mean cBP were both overestimated by oscillometry, with mean differences of -8.9 ± 5.5 mmHg and -6.4 ± 5.1 mmHg compared with the FFR and -10.6 ± 6.3 mmHg and -5.9 ± 6.2 mmHg with the FF. Non-invasive systolic cBP compared accurately with the high-fidelity FFR measurements, demonstrating a low bias (≤5 mmHg) and high precision (SD ≤ 8 mmHg). These criteria were not met when using the FF measurements. Invasively derived average Ao-brachial abPWV was 7.0 ± 1.4 m/s and that of Ao-tibial atPWV was 9.1 ± 1.8 m/s. Non-invasively estimated PWV based on the reflected wave transit time did not correlate with abPWV or with atPWV. In conclusion, we demonstrate the advantages of a novel method of validation for non-invasive cBP monitoring devices using acknowledged gold standard FFR wire transducers and the possibility to easily measure PWV during coronary angiography with the impact of cardiovascular risk factors.

Fractional flow reserve and non-hyperemic indices: Essential tools for percutaneous coronary interventions.

Hemodynamical evaluation of a coronary artery lesion is an important diagnostic step to assess its functional impact. Fractional flow reserve (FFR) received a class IA recommendation from the European Society of Cardiology for the assessment of angiographically moderate stenosis. FFR evaluation of coronary artery disease offers improvement of the therapeutic strategy, deferring unnecessary procedures for lesions with a FFR > 0.8, improving patients' management and clinical outcome. Post intervention, an optimal FFR > 0.9 post stenting should be reached and > 0.8 post drug eluting balloons. Non-hyperemic pressure ratio measurements have been validated in previous studies with a common threshold of 0.89. They might overestimate the hemodynamic significance of some lesions but remain useful whenever hyperemic agents are contraindicated. FFR remains the gold standard reference for invasive assessment of ischemia. We illustrate this review with two cases introducing the possibility to estimate also non-invasively FFR from reconstructed 3-D angiograms by quantitative flow ratio. We conclude introducing a hybrid approach to intermediate lesions (DFR 0.85-0.95) potentially maximizing clinical decision from all measurements.

iFR/FFR/IVUS Discordance and Clinical Implications: Results From the Prospective Left Main Physiology Registry.

OBJECTIVES: This study aimed to assess discordance between results of instantaneous wave-free ratio (iFR), fractional flow reserve (FFR), and intravascular ultrasound (IVUS) in intermediate left main coronary (LM) lesions, and its impact on clinical decision making and outcome. METHODS: We enrolled 250 patients with a 40%-80% LM stenosis in a prospective, multicenter registry. These patients underwent both iFR and FFR measurements. Of these, 86 underwent IVUS and assessment of the minimal lumen area (MLA), with a 6 mm2 cutoff for significance. RESULTS: Isolated LM disease was recognized in 95 patients (38.0%), while 155 patients (62.0%) had both LM disease and downstream disease. In 53.2% of iFR+ and 56.7% of FFR+ LM lesions, the measurement was positive in only one daughter vessel. iFR/FFR discordance occurred in 25.0% of patients with isolated LM disease and 36.2% of patients with concomitant downstream disease (P=.049). In patients with isolated LM disease, discordance was significantly more common in the left anterior descending artery and younger age was an independent predictor of iFR-/FFR+ discordance. iFR/MLA and FFR/MLA discordance occurred in 37.0% and 29.4%, respectively. Within 1 year of follow-up, major cardiac adverse events (MACE) occurred in 8.5% and 9.7% (P=.763) of patients whose LM lesion was deferred or revascularized, respectively. Discordance was not an independent predictor of MACE. CONCLUSIONS: Current methods of estimating LM lesion significance often yield discrepant findings, complicating therapeutic decision-making.

Autonomic nervous system assessment using heart rate variability.

The role of the autonomic nervous system in the onset of supraventricular and ventricular arrhythmias is well established. It can be analysed by the spontaneous behaviour of the heart rate with ambulatory ECG recordings, through heart rate variability measurements. Input of heart rate variability parameters into artificial intelligence models to make predictions regarding the detection or forecast of rhythm disorders is becoming routine and neuromodulation techniques are now increasingly used for their treatment. All this warrants a reappraisal of the use of heart rate variability for autonomic nervous system assessment.Measurements performed over long periods such as 24H-variance, total power, deceleration capacity, and turbulence are suitable for estimating the individual basal autonomic status. Spectral measurements performed over short periods provide information on the dynamics of systems that disrupt this basal balance and may be part of the triggers of arrhythmias, as well as premature atrial or ventricular beats. All heart rate variability measurements essentially reflect the modulations of the parasympathetic nervous system which are superimposed on the impulses of the adrenergic system. Although heart rate variability parameters have been shown to be useful for risk stratification in patients with myocardial infarction and patients with heart failure, they are not part of the criteria for prophylactic implantation of an intracardiac defibrillator, because of their high variability and the improved treatment of myocardial infarction. Graphical methods such as Poincaré plots allow quick screening of atrial fibrillation and are set to play an important role in the e-cardiology networks. Although mathematical and computational techniques allow manipulation of the ECG signal to extract information and permit their use in predictive models for individual cardiac risk stratification, their explicability remains difficult and making inferences about the activity of the ANS from these models must remain cautious.

Development of a Method for Producing oxLDL: Characterization of Their Effects on HPV-Positive Head and Neck Cancer Cells.

Cardiovascular diseases (CVD) and cancers are the two main causes of death worldwide. The initiation and progression of atherosclerosis is, in large part, caused by oxidized low-density lipoproteins (oxLDL); interestingly, oxLDL may also play a role in cancer cell metabolism and migration. As oxLDL are generally obtained by tedious ultracentrifugation procedures, "home-made" oxLDL were obtained by (i) applying a purification kit to isolate LDL and VLDL from human plasma; (ii) isolating LDL from VLDL by gel permeation chromatography (GPC); and (iii) oxidating LDL through CuSO4 incubation. On three HPV-positive head and neck cancer cells (HNCC) (93VU-147T, UM-SCC47, and UPCI-SCC154), cell migration was assessed using Boyden chambers, the Wnt/ß-catenin pathway was analyzed by Western Blotting, and the expression of two oxLDL receptors, LOX-1 and CD36, in response to oxLDL exposure, was analysed by immunofluorescence. Our data indicate: (a) a non-significant difference between reference and "home-made" oxLDL; (b) a decreased migration, parallel to an inhibition of the ß-catenin pathway; and (c) an increase of CD36 and LOX-1 expression in all HNCC. In conclusion, we successfully produced oxLDL. Our results demonstrate a decrease in HNCC migration after oxLDL exposure, and an increased expression of LOX-1 and CD36 associated with lipid uptake.

An uncommon case of complete AV block.

BACKGROUND: Granulomatosis with polyangiitis (GPA) is a rare systemic inflammatory disorder characterized by vasculitis of the small vessels, as well as necrotizing granulomatous lesions, affecting mainly upper and lower respiratory tracts, lungs and kidneys. Cardiac involvement has traditionally been a rare manifestation of GPA, with misleading clinical presentation until late stages. Cardiac conducting tissue involvement is a rare and potentially life-threatening complication. CASE PRESENTATION: We report the case of a 45-year-old man diagnosed with GPA with typical symptoms, but also complete atrioventricular (AV) block at the onset of the disease. The echocardiogram was unremarkable but the cardiac magnetic resonance (CMR) showed evidence of inflammation of the basal and septal ventricle walls. Despite effective immunosuppressive therapy, a permanent pacemaker was required for recurring complete AV block. DISCUSSION: Conduction system abnormalities are a rare manifestation of GPA, due to granulomatous lesions within the conduction system, or arteritis of the atrioventricular nodal artery. Patients are often asymptomatic, so careful and regular screening for cardiac involvement in this multi-system condition is required, often with echocardiogram, electrocardiogram (ECG) monitoring and CMR. Early immunosuppressive treatment may reverse a complete AV block but a pacemaker implantation may sometimes be necessary.

Role of the autonomic nervous system and premature atrial contractions in short-term paroxysmal atrial fibrillation forecasting: Insights from machine learning models.

BACKGROUND: Machine learning and deep learning techniques are now used extensively for atrial fibrillation (AF) screening, but their use for AF crisis forecasting has yet to be assessed in a clinical context. AIMS: To assess the value of two machine learning algorithms for the short-term prediction of paroxysmal AF episodes. METHODS: We conducted a retrospective study from an outpatient clinic. We developed a deep neural network model that was trained for a supervised binary classification, differentiating between RR interval variations that precede AF onset and RR interval variations far from any AF. We also developed a random forest model to obtain forecast results using heart rate variability variables, with and without premature atrial complexes. RESULTS: In total, 10,484 Holter electrocardiogram recordings were screened, and 250 analysable AF onsets were labelled. The deep neural network model was able to distinguish if a given RR interval window would lead to AF onset in the next 30 beats with a sensitivity of 80.1% (95% confidence interval 78.7-81.6) at the price of a low specificity of 52.8% (95% confidence interval 51.0-54.6). The random forest model indicated that the main factor that precedes the start of a paroxysmal AF episode is autonomic nervous system activity, and that premature complexes add limited additional information. In addition, the onset of AF episodes is preceded by cyclical fluctuations in the low frequency/high frequency ratio of heart rate variability. Each peak is itself followed by an increase in atrial extrasystoles. CONCLUSIONS: The use of two machine learning algorithms for the short-term prediction of AF episodes allowed us to confirm that the main cause of AF crises lies in an imbalance in the autonomic nervous system, and not premature atrial contractions, which are, however, required as a final firing trigger.

Lipid-lowering therapy and risk-based LDL-C goal attainment in Belgium: DA VINCI observational study.

BACKGROUND: Cardiovascular disease (CVD) is one of the leading causes of death in Belgium. Current strategies for the prevention and management of CVD focus on reducing low-density lipoprotein cholesterol (LDL-C) levels. This analysis assessed whether LDL-C goals, recommended by the European Society of Cardiology (ESC)/European Atherosclerosis Society (EAS) guidelines, were being achieved in a Belgian study population. METHODS: The cross-sectional, observational, DA VINCI study enrolled patients prescribed lipid-lowering therapy (LLT) between 21 June 2017 and 20 November 2018. Data for patients from Belgium were extracted for this country-specific analysis. Primary endpoint was the proportion of patients who achieved 2016 ESC/EAS risk-based LDL-C goals; attainment of 2019 risk-based LDL-C goals was evaluated post hoc. RESULTS: Of 497 enrolled patients, 41% were female and mean age was 68 years. Among subjects with an LDL-C measurement on stabilised LLT, moderate-intensity statin monotherapy was the most prescribed LLT regimen (59%). Overall, 63% of patients achieved their risk-based LDL-C goals according to the 2016 ESC/EAS guidelines. Among patients with established ASCVD, risk-based LDL-C goal attainment was higher in patients with peripheral arterial disease (53%) than patients with coronary (37%) and cerebrovascular disease (42%). According to the updated 2019 ESC/EAS guidelines, less than half (41%) of patients achieved their risk-based LDL-C goal. The proportion of primary and secondary prevention patients who achieved 2019 risk-based LDL-C goals was 59% and 18%, respectively. CONCLUSION: These findings reveal a large gap between the LDL-C goals advocated by the ESC/EAS and the levels achieved in routine clinical practice in Belgium.

Successful Crossing of Complex Radial and Brachial Artery Anatomy Using a New Approach: Railtracking.

BACKGROUND Use of the distal transradial artery (dTRA) for coronary angiography and PCI has been shown to be feasible and potentially has multiple advantages over proximal TRA regarding vascular complications, but when larger introducer sheaths (>6 Fr) are used, severe spasm and pain can be induced. However, in comparison with the more proximal part of the radial artery, the distal part is on average 0.5 mm smaller. As a consequence, when using dTRA, the use of slender techniques and miniaturization should be preferred to avoid a large sheath-to-artery mismatch, which has unfavorable consequences. A new approach named RailTracking, using a conventional 6 Fr or 7 Fr guiding catheter and a vascular dilator (the Railway Sheathless Access System [RS] from Cordis Company), allows use of distal arterial access without need for a sheet introducer. CASE REPORT We present 2 clinical cases with a difficult arterial access that were successfully managed using the RailTracking technique by dTRA access. In the first one, the conventional methods of arterial crossing failed because of the tortuosity and severe calcifications in the forearm and brachial artery. In the second case, the proximal TRA was occluded. Having arterial access on the dTRA and using the RailTracking allowed us to safely perform the interventions without need for vascular access site conversion. CONCLUSIONS A new approach, RailTracking, which includes sheathless distal radial access and use of the RSS system could potentially decrease the vascular complications and facilitate the crossing, even in cases of complex vessels anatomy.

Intracoronary Lithotripsy in Calcified Coronary Lesions: A Multicenter Observational Study.

OBJECTIVES: The aim of this study was to evaluate the feasibility, effectiveness, and safety of coronary intravascular lithotripsy (IVL; Shockwave Medical) in the treatment of severe coronary artery calcification (CAC) in a real-world setting. BACKGROUND: Severe CAC can be an arduous obstacle in interventional cardiology, often leading to suboptimal results of percutaneous coronary interventions (PCI). Coronary IVL is a novel technique that modulates severe CAC, thereby facilitating stent implantation. METHODS AND RESULTS: In this multicenter observational study, data from 134 IVL procedures in 5 Belgian hospitals were prospectively obtained. Successful delivery of the IVL catheter was achieved in all cases but 1 (99.3%). The primary endpoint was final overall procedural success, which was obtained in 88.1% of cases, an aggregate of 92.6% in de novo lesions and 77.5% in stent underexpansion or in-stent restenosis (ISR). IVL therapy effect was considered successful by the operators in 94% of cases, with 68.7% achieving optimal and 25.3% achieving suboptimal results. The 1-month major adverse cardiovascular event rate was 3%, including 2 cardiovascular deaths (1 in-stent thrombosis and 1 coronary artery perforation). CONCLUSIONS: This real-world experience suggests that Shockwave IVL is a feasible, effective, and safe technique for the treatment of heavily calcified coronary lesions.

Stent visualization methods to guide percutaneous coronary interventions and assess long-term patency.

Evaluation of acute percutaneous coronary intervention (PCI) results and long-term follow-up remains challenging with ongoing stent designs. Several imaging tools have been developed to assess native vessel atherosclerosis and stent expansion, improving overall PCI results and reducing adverse cardiac events. Quantitative coronary analysis has played a crucial role in quantifying the extent of coronary artery disease and stent results. Digital stent enhancement methods have been well validated and improved stent strut visualization. Intravascular imaging remains the gold standard in PCI guidance but adds costs and time to the procedure. With a recent shift towards non-invasive imaging assessment and coronary computed tomography angiography imaging have shown promising results. We hereby review novel stent visualization techniques used to guide PCI and assess stent patency in the modern PCI era.

Effect of Oxidized Low-Density Lipoprotein on Head and Neck Squamous Cell Carcinomas.

Cardiovascular disease (CVD) and cancer are two major causes of death worldwide. The question is, "Could there be a link between these two pathologies in addition to their shared, common risk factors?" To find some answers, we studied the effect of oxidized low-density lipoproteins (oxLDL) on head and neck cancer (HNC) cell lines, since oxLDL is a major contributor to atherosclerosis and the principal cause of CVD. In this study, we exposed three HNC cell lines (Detroit 562, UPCI-SCC-131 and FaDu) to oxLDL. We investigated two oxLDL receptors, CD36 and Lox-1, using immunofluorescence. Cancer cell migration was evaluated using Boyden chambers and the Wnt/ß-catenin pathway was investigated using Western blotting. We demonstrated that the expression of CD36 and Lox-1 significantly increases after exposure to oxLDL. Moreover, we found that oxLDL reduces the migration of HNC cell lines, an observation that is in line with an increased degradation of ß-catenin under oxLDL. Finally, the inhibition of CD36 with sulfosuccinimidyl oleate (SSO) reverses the inhibition of cell migration. In conclusion, we report that oxLDL seems to induce an increase in CD36 expression on HNC cell lines, enhancing the uptake of these lipids in cells to finally decrease cancer cell migration via the CD36/ß-catenin pathway.

The evolution of the CTO-PCI landscape in Belgium and Luxembourg: a four-year appraisal.

BACKGROUND: To chart the evolution of the CTO-PCI landscape in Belgium and Luxembourg, the Belgian Working Group on Chronic Total Occlusions (BWGCTO) was established in 2016. METHODS: Between May 2016 and December 2019, patients undergoing a CTO-PCI treatment were prospectively and consecutively enrolled. Twenty-one centres in Belgium and one in Luxembourg participated. Individual operators had mixed levels of expertise in treating CTO lesions. Demographic, angiographic, procedural parameters and incidence of major adverse cardiac and cerebrovascular events (MACCE) were systematically registered. RESULTS: Over a four-year enrolment period, 1832 procedures were performed in 1733 patients achieving technical success in 1474 cases (80%), with an in-hospital MACCE rate of 2.3%. Fifty-nine (3%) cases were re-attempt procedures of which 41 (69%) were successful. High-volume centres treated more complex lesions (mean J-CTO score: 2.15 ± 1.21) as compared to intermediate (mean J-CTO score: 1.72 ± 1.23; p < 0.001) and low-volume centres (mean J-CTO score: 0.99 ± 1.21; p = 0.002). Despite this, success rates did not differ between centres (p = 0.461). Overall success rates did not differ over time (p = 0.810). High-volume centres progressively tackled more complex CTOs while keeping success rates stable. In all centres, the most applied strategy was antegrade wire escalation (83%). High-volume centres more often successfully applied antegrade dissection and re-entry and retrograde techniques in lesions with higher complexity. CONCLUSION: With variable experience levels, operators treated CTOs with high success and relatively few complications. Although AWE remains the most used technique, it is paramount for operators to be skilled in all contemporary techniques in order to be successful in more complex CTOs.