Circle of Vieussens: Its Importance in the Presence of Significant Coronary Artery Stenosis in a 26-Year-Old Female With Kawasaki Disease.

In patients with coronary artery disease (CAD), collateral circulation aids in sustaining myocardial perfusion and cardiac function. The circle of Vieussens is a rare collateral pathway between the right coronary artery and the left anterior descending artery (LAD) that plays a significant role specifically in patients with chronic total occlusions (CTOs). This article presents a unique case of the circle of Vieussens in a 26-year-old Asian female with a history of Kawasaki disease and CTO of the proximal LAD. Despite the CTO, the patient remains asymptomatic and maintains normal left ventricular function, attributed to an effective collateral network including a right-to-left arterial ring providing TIMI 3 flow. The case illustrates the crucial role of collateral circulation in managing complex coronary anomalies and underscores the need for comprehensive cardiac evaluations in patients with Kawasaki disease. This finding also highlights the potential of the circle of Vieussens as a lifesaving alternate conduit in severe CAD scenarios.

Role of calcification in J-CTO score: a viewpoint of intraplaque guidewire tracking techniques.

BACKGROUND: As the burden and distribution of calcification within chronic total occlusion (CTO) lesions can be diverse, its effect on CTO recanalization using multiple devices and techniques is debatable. This study investigated the role of calcification in wiring-based intraplaque tracking techniques for CTO recanalization. METHODS: A modified J-CTO score without counting calcification was used to analyze the procedures of 458 consecutive patients who underwent CTO interventions. Failed guidewire crossing and intraplaque tracking were considered procedural failures. Recanalization time details were analyzed for successful procedures. RESULTS: In patients with calcified CTO, the rate of procedural success only significantly declined to be lower than that of noncalcified CTO when the modified J-CTO score was ≥3 (77% vs. 94%, p = 0.008). In 422 patients with successful procedures, the presence of calcification was irrelevant to guidewire crossing time, but was accompanied with longer time from guidewire cross to final angiogram when the modified J-CTO score was 1-2 (53 ± 35 vs. 35 ± 17 [noncalcified] min, p < 0.001). Multivariate analyses showed that calcification was independently associated with procedural failure (odds ratio [OR] = 5.1, 95% confidence interval [CI] = 1.4-18.3) in lesions with modified J-CTO ≥3, and prolonged angioplasty/stenting procedures >60 min (OR = 4.8, 95% CI = 2.2-10.2) in successfully recanalized lesions with modified J-CTO score 1-2. CONCLUSIONS: Using intraplaque guidewire tracking, calcification was unfavorable for very difficult CTO lesions, and caused prolongation of angioplasty time for lesions with moderate complexity. This suggested that the role of calcification in the J-CTO score could be altered when different recanalization techniques were applied for CTO interventions.

Since several commonly used scoring systems for grading the difficulty of CTO-PCI are derived from multiple recanalization techniques and devices, their application should be fundamental. However, most CTO interventionists usually have their own favored recanalization techniques in the real-world. As one of the parameters of J-CTO score, the findings of the study suggest that the interpretation of calcification during CTO-PCI could be altered and should be cautious if different recanalization technique was used.

Evaluation of acute and midterm outcomes after complex combined antegrade/retrograde recanalization for occlusions of the femoropopliteal and infrapopliteal arteries.

BACKGROUND: When antegrade recanalization of femoropopliteal and/or infrapopliteal occlusions fails, retrograde access has become an established option. To evaluate the results of combined antegrade and retrograde recanalization of femoropopliteal and infrapopliteal occlusions, patients undergoing secondary retrograde recanalization attempts were analyzed retrospectively. METHODS: The primary end point was the success of the procedure (successful occlusion crossing using the antegrade/retrograde technique). Secondary end points include complication rate, primary patency and target lesion revascularization (TLR) rate, amputation rate, changes in ankle-brachial index, and Rutherford-Becker class. Predictors for procedure failure and TLR were analyzed. RESULTS: We included 888 patients: 362 with femoropopliteal (group 1), 353 with infrapopliteal (group 2), and 173 with multilevel (group 3) recanalization. Critical limb-threatening ischemia was present in group 1, 2, and 3 in 36%, 62%, and 76% of patients, respectively. The intervention was successful in 92.5%, 93.8%, and 90.8% of the respective cases (P = .455). The overall peri-interventional complication rate was 7.2%. At 6, 12, and 24 months, primary patency was highest in group 1 (63.9%, 45.8%, and 33.3%), followed by group 3 (59.8%, 46.1%, and 33.3%), and group 2 (58.5%, 43.1%, and 30.4%; P = .537). The risk of undergoing repeated TLR within 24 months was 31.4% for group 1, 39.1% for group 2, and 45.7% for group 3. At 24 months, the survival rates in groups 1, 2, and 3 were 93.8%, 79.4%, and 87.5%, respectively. Over 24 months, 75 patients (8.4%) had to undergo amputation. Significant improvements in both ankle-brachial index and Rutherford-Becker class were present at discharge as well as at 6, 12, and 24 months (P < .001). Dialysis dependency was a predictor of unsuccessful antegrade/retrograde recanalization (P = .048). Lesion length (P = .0043), dialysis (P = .033), and recanalization level (P = .013) increase the risk of TLR. CONCLUSIONS: Using a combined antegrade/retrograde access, recanalization of occluded femoropopliteal and/or infrapopliteal arteries can be achieved in a large number of cases. Owing to the high rate of repeated TLR across all lesion localizations, the indication for antegrade and retrograde recanalization may be limited to patients with critical limb-threatening ischemia.

External validation of the JR-CTO score in retrograde chronic total occlusion intervention: from the PROGRESS-CTO registry.

In complex chronic total occlusion (CTO) percutaneous coronary interventions (PCI), a retrograde crossing strategy is often necessary. Recently, the Japanese retrograde (JR) CTO score was developed using a simple 4-item tool. This score showed a good performance in predicting guidewire crossing failure in patients undergoing primary retrograde CTO PCI. We evaluated the JR-CTO score's performance in patients treated at 44 centers between 2013 and 2024 as part of the Prospective Global Registry for the Study of CTO Intervention (PROGRESS-CTO). In an independent cohort, although the JR-CTO score showed an association with crossing and technical failure, its predictive ability for both outcomes was modest.

Outcomes following antegrade-only versus retrograde chronic total occlusion percutaneous coronary intervention: insights from the CCTOP registry.

Background: Chronic total occlusion (CTO) percutaneous coronary intervention (PCI) can be performed using an antegrade-only (AO) approach or a retrograde approach (RA). Whether an RA carries a higher risk of complications needs further investigation. Methods: The Canadian CTO PCI (CCTOP) was a multicenter, prospective, investigator-initiated cohort study conducted at 6 experienced centers across Canada between March 2014 and October 2019. Patients who underwent an RA were compared to AO patients. The primary endpoint was in-hospital major adverse cardiac events (MACE), defined as death, any post-PCI cardiac enzyme elevation, urgent revascularization, and tamponade. A multivariable analysis was performed to control for potential confounders. Results: A total of 1033 patients were included in the study, and an RA was used in 48.4% of the cases. The RA was associated with higher lesions complexity (J-CTO score 2.7 ± 1.1 vs 2.3 ± 1.1, P < .001) and lower technical success (81.2% vs 91.5%, P < .001). The risk of in-hospital MACE was higher with the RA (10.2% vs 4.7%, P < .001), and all deaths occurred in the RA group (0.8% vs 0%, P = .038). In the multivariable model, the RA remained associated with an increased risk of MACE (OR, 2.25; 95% CI, 1.26 to 4.02). Conclusions: Our experience confirms that the RA is associated with an independent increased risk of in-hospital MACE when compared with an AO approach.

[How to solve difficult side branch access: case report and literature review]. / Je n'arrive pas à passer mon guide dans la branche fille ; cas clinique et revue de la littérature.

We present the case of a 53-year-old patient with history of hypertension and dyslipidemia, admitted for effort-induced angina. Coronary angiography revealed two-vessel disease with severe stenosis of the LAD- Diagonal bifurcation (MEDINA 1-1-1). This lesion was considered complex regarding the severe stenosis of the bifurcation core, the angulation <45°, and the severity and length of the diagonal lesion. The procedure was planned according to a TAP technique. The flow in the diagonal was however lost after stenting the main vessel causing an ST elevation with chest pain. It was subsequently recovered using the rescue jailed balloon technique before re-crossing the stent struts of the LAD using a Gaia First® (Asahi) guidewire. The aim of this case report is to illustrate some pitfalls that can be encountered in bifurcation percutaneous interventions and to present technical solutions to solve difficult side branch access issues through a literature review.

Guide catheter extension use in chronic total occlusion percutaneous coronary intervention: insights from the PROGRESS CTO registry.

There are limited data on the use of guide catheter extensions (GCE) during chronic total occlusion (CTO) percutaneous coronary intervention (PCI). We examined the frequency and temporal trends of GCE use in a large multicenter CTO-PCI registry and compared the clinical and angiographic characteristics and outcomes of cases with vs without GCE use. A GCE was used in 4106 of 14 521 CTO PCIs (28%) with increasing frequency from 18.8% in 2012 to 29.9% in 2023. The most used GCE size was 6 French (Fr) (45%), followed by 7 Fr (34%), and 8 Fr (21%). CTOs that required GCE use were more likely to have unfavorable lesion characteristics such as moderate-to-severe calcification (59% vs 40%, P < .0001), moderate-to-severe tortuosity (35% vs 28%, P < .0001), proximal cap ambiguity (39% vs 33%, P < .0001), and had higher J-CTO scores (2.78 ± 1.15 vs 2.20 ± 1.27, P < .0001). Advanced techniques like the retrograde approach (44% vs 24%, P < .0001) and antegrade dissection and re-entry (28% vs 17%, P < .0001) were more likely to be used in GCE cases. Technical success (86.6% vs 86.8%, P = .816) was similar between the 2 groups. However, major adverse cardiovascular events (MACE) (3.8% vs 2.4%, P < .0001) and procedural complications (11.2% vs 8.7%, P < .0001) were more frequent in the GCE group. In summary, GCE use in CTO PCI significantly increased between 2012 and 2023. Cases that required GCEs were more complex and had similar technical success, but higher incidence of MACE compared with cases that did not require GCEs.

Peripheral artery disease in chronic total occlusion percutaneous coronary intervention.

Background: The impact of peripheral artery disease (PAD) on the outcomes of chronic total occlusion (CTO) percutaneous coronary intervention (PCI) is not well studied. Methods: We analyzed the association of PAD with CTO-PCI outcomes using data from the PROGRESS-CTO registry of procedures performed at 47 centers between 2012 and 2023. Results: The prevalence of PAD among 12 961 patients who underwent CTO PCI during the study period was 13.9% (1802). PAD patients were older, more likely to be current smokers, and had higher rates of dyslipidemia, diabetes, cerebrovascular disease, hypertension, prior myocardial infarction, PCI, and coronary artery bypass graft surgery. Their PROGRESS-CTO (1.35 vs 1.22; P < .001) and J-CTO (2.63 vs 2.33; P < .001) scores were higher, lesion length was longer, and angiographic characteristics were more complex. Their access site was more likely to be bifemoral (33.6% vs 30.9%; P = .024) compared with patients with no PAD. Technical (82.9% vs 87.7%; P < .001) and procedural (80.5% vs 86.6%; P < .001) success rates were lower in patients with PAD, while the incidence of major adverse cardiovascular events (MACE) was higher (3.1% vs 1.8%; P < .001), with higher mortality (0.8% vs 0.4%; P = .034), acute myocardial infarction rate (0.9% vs 0.4%; P = .010), and perforations rate (6.6% vs 4.5%; P < .001). In multivariable analysis, PAD was associated with higher MACE (odds ratio [OR]: 1.53; 95% CI, 1.01-2.26; P = .038) and lower technical success (OR: 0.82; 95% CI, 0.69-0.99; P = .039). Conclusions: PAD patients undergoing CTO PCI have higher comorbidity burden, more complex CTOs, higher MACE, and lower technical success.

Intravascular lithotripsy in heavily calcified chronic total occlusion: procedural and one-year clinical outcomes.

BACKGROUND: Calcification within chronic total occlusions (CTO) is strongly associated with worse outcomes. Despite the excellent success and safety of intravascular lithotripsy (IVL) in heavily calcified lesions, evidence in CTO remains scarce. AIM: This study aimed to evaluate the procedural and long-term clinical outcomes of IVL in heavily calcified CTO. METHODS: Patients who underwent IVL between 2019 and 2024 from an ongoing prospective multicenter registry were eligible for inclusion. Patients were therefore classified in CTO and non-CTO groups. The efficacy and safety endpoints of CTO percutaneous coronary interventions were defined according to the CTO-ARC consensus. In-hospital major adverse cardiovascular events (MACE) included cardiac death, nonfatal myocardial infarction and target lesion revascularization (TVR). RESULTS: A total of 404 patients underwent IVL, of which the treated lesion was a CTO in 33 (8.2%). The mean J-CTO score was 2.3 ± 1.1. Device success showed no significant difference between CTO and non-CTO groups (100% vs 98.4%; p = 0.35). Comparable technical success with residual stenosis <30% was observed in both groups (90.1% in CTO vs 89.2% in non-CTO, p = 0.83). The incidence of MACE was similar across groups during hospital stays (CTO 6.0% vs. non-CTO 1.9%, p = 0.12), at 30-day (CTO 9.1% vs. non-CTO 3.0%, p = 0.07), and at 12-month follow-up (CTO 9.1% vs. non-CTO 7.3%, p = 0.70). CONCLUSION: IVL provides high procedural success and consistent clinical outcomes in both CTO and non-CTO cases, reinforcing its role in managing heavily calcified coronary lesions.

Polyploid Giant Cancer Cells: A Distinctive Feature in the Transformation of Epithelial Cells by High-Risk Oncogenic HCMV Strains.

Human cytomegalovirus (HCMV) infection is common in tumor tissues across different types of cancer. While HCMV has not been recognized as a cancer-causing virus, numerous studies hint at its potential role in cancer development where its presence in various cancers corresponds with the hallmarks of cancer. Herein, we discuss and demonstrate that high-risk HCMV-DB and BL strains have the potential to trigger transformation in epithelial cells, including human mammary epithelial cells (HMECs), ovarian epithelial cells (OECs), and prostate epithelial cells (PECs), through the generation of polyploid giant cancer cells (PGCCs). A discussion is provided on how HCMV infection creates a cellular environment that promotes oncogenesis, supporting the continuous growth of CMV-transformed cells. The aforementioned transformed cells, named CTH, CTO, and CTP cells, underwent giant cell cycling with PGCC generation parallel to dedifferentiation, displaying stem-like characteristics and an epithelial-mesenchymal transition (EMT) phenotype. Furthermore, we propose that giant cell cycling through PGCCs, increased EZH2 expression, EMT, and the acquisition of malignant traits represent a deleterious response to the cellular stress induced by high-risk oncogenic HCMV strains, the latter being the origin of the transformation process in epithelial cells upon HCMV infection and leading to adenocarcinoma of poor prognosis.

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.

Manual Microcatheter-tip Modification: A bailout option for difficult "tip-in" technique during chronic total occlusion percutaneous coronary intervention.

The retrograde approach in chronic total occlusion (CTO) interventions often encounters significant challenges, particularly, when aligning the retrograde microcatheter (MC) with the antegrade system is difficult, complicating or even preventing standard externalization. To address these issues, techniques like the "tip-in" have proven to be effective backup strategies. We introduce the "Manual Microcatheter-tip Modification" (MMM) technique as an alternative when the "tip-in" method faces complications. We present a case of a left anterior descending CTO where MMM was successfully employed for the first time, enabling successful revascularization by manually modifying the MC tip to engage the retrograde guidewire. We explore the technical details within the framework of contemporary CTO PCI. This new technique could enhance the management of CTO interventions, offering innovative solutions when traditional externalization methods are problematic.

Who Should Undergo Chronic Total Occlusions Percutaneous Coronary Intervention and When?: An Evidence-Based Approach to the Patient Referred for Percutaneous Coronary Intervention of Chronic Total Occlusion.

Chronic total occlusions (CTO) of the coronary arteries are common among patients presenting to the cardiac catheterization laboratory, and data suggests a worse overall prognosis in patients with CTOs. Percutaneous coronary intervention (PCI) of CTOs has been shown to improve anginal symptoms in observational studies and in a limited number of randomized trials. However, CTO PCI has not been shown to lead to a reduction in other important end points such as myocardial infarction or death. Furthermore, despite recent advances in the field, CTO PCI still carries higher risks and a lower likelihood of success compared with non-CTO PCI. Thus, determining which patients may be appropriate for CTO PCI is challenging and must involve a comprehensive risk-benefit analysis and discussion with the patient. Therefore, we review the currently available data regarding CTO PCI, including the clinical outcomes, the role of preprocedural ischemia testing, and various procedural success and risk stratification scores. Finally, we present our approach to the patient referred for CTO PCI.

The Ramus Intermedius: A Bridge to Survival in the Setting of Triple-Vessel Total Occlusion.

Coronary artery disease continues to remain the leading cause of mortality worldwide. Coronary blood supply is provided through the right and left main coronary arteries. The left main coronary artery (LMCA) in turn gives rise to the left anterior descending (LAD) and left circumflex (LCX) arteries. In some cases, LMCA may trifurcate into the ramus intermedius (RI) in addition to the LAD and LCX arteries. Atherosclerotic plaque formation and rupture with subsequent clot formation and occlusion of coronary arteries are the underlying mechanisms of myocardial infarction. Though the clinical implications of the presence of ramus intermedius (RI) are controversial some data suggest that the RI is associated with an increased risk of atherosclerotic plaque formation in the LMCA and the proximal LAD. Conversely, it has been proposed that the RI provides an additional collateral source of blood supply to the myocardium and may potentially contribute to improved survival. Case reports tout the benefits of RI, specifically in the setting of multivessel coronary artery occlusions. Whether it increases the risk of atherosclerotic plaque formation or whether it is protective has yet to be determined. We present a case of a 58-year-old male who presented with acute coronary syndrome and cardiogenic shock due to total ostial occlusion of LAD. The patient had also chronic total occlusions of the right coronary artery and LCX but a patent RI, which was the only source of blood supply to the myocardium and practically determined the patient's survival. Additionally, we performed a literature review to identify similar cases, to support RI's potentially protective role in enhancing survival.

Ten tips and tricks for successful distal true lumen wiring from three-dimensional wiring experts.

Antegrade wiring is the dominant method used in chronic total occlusion percutaneous coronary intervention (CTO PCI). However, distal cap puncture for distal true lumen wiring remains a significant barrier toward success. Three-dimensional (3D) fluoroscopic wiring can improve the speed, safety, and success of distal cap wiring. In this article, we provide 10 tips for every CTO interventionist to use when performing 3D wiring in distal true lumen wiring.

Effectiveness and safety of a novel modified homemade snare in retrograde percutaneous coronary intervention for chronic total occlusion lesions: a retrospective cohort study.

Background: The use of a commercial snare for retrograde chronic total occlusion (CTO) percutaneous coronary intervention (PCI) is time-consuming and expensive. This study aimed to evaluate the benefits and complications of a novel modified homemade snare (MHS) for retrograde CTO-PCI. Methods: This retrospective cohort study included patients with CTO who underwent retrograde PCI with guidewire snaring between January 2017 and June 2022 at Beijing Anzhen Hospital. The patients were divided into the MHS and gooseneck snare (GS) groups according to the devices used for externalization. Clinical, procedural, and angiographic data were collected. Results: Ninety patients (46 with MHS and 44 with GS) were included. There was no significant difference in the location of the CTO vessel between the MHS and GS groups, and the target CTO vessel was mainly located in the right coronary artery (RCA) in both groups (73.9% and 68.2% respectively). There were no significant differences in the J-CTO (Multicenter CTO Registry in Japan) and PROGRESS-CTO (Prospective Global Registry for the Study of Chronic Total Occlusion Intervention) scores between the two groups. More patients in the MHS group had lesions with ambiguous proximal caps compared with the GS group (54.3% vs. 31.8%, P=0.04). Retrograde wire crossing technique was used more in the GS group (54.5% vs. 41.3%, P=0.04), while reverse-controlled antegrade and retrograde subintimal tracking (CART) technique was used more in the MHS group (58.7% vs. 45.5%, P=0.037). The mean guidewire capture time was shorter in the MHS group than in the GS group (2.7±0.6 vs. 3.4±0.7 min, P<0.001). One case of delayed pericardial tamponade was observed in the MHS group. No other complications occurred. Conclusions: MHS appears to facilitate externalization in retrograde PCI for complex CTO lesions.

Efficacy of revascularization in CTO patients based on hibernating myocardium therapy.

BACKGROUND: The effectiveness of percutaneous coronary intervention (PCI) for chronic total occlusion (CTO) is still uncertain, especially for patients with ischemic left ventricular dysfunction. This study aimed to assess hibernating myocardium (HM), as determined by single-photon emission computed tomography (SPECT) and 18F-FDG positron emission tomography (PET), and to compare the benefits of PCI and optimal medical therapy (OMT). METHODS: A retrospective study collected data from 332 patients with CTO and ischemic left ventricular dysfunction. The study compared patients who underwent PCI or OMT via propensity score matching (PSM) analysis which was performed with a 1:2 matching protocol using the nearest neighbour matching algorithm. The primary endpoint of the study was the occurrence of major adverse cardiac events (MACE), defined as a composite of cardiac death, readmission for worsening heart failure (WHF), revascularization and myocardial infarction (MI). RESULTS: After PSM, there were a total of 246 individuals in the PCI and OMT groups. Following Cox regression, hibernating myocardium/total perfusion defect (HM/TPD) was identified as an independent risk factor (hazard ratio (HR): 1.03, 95% confidence interval (CI): 1.008-1.052, p = .007). The cut-off value of HM/TPD was 38%. The results of the subgroup analysis suggest that for patients with HM/TPD >38%, the OMT group had a greater risk of MACE (p = .035). A sensitivity analysis restricting patients with single-vessel CTO lesions, HM/TPD remained an independent predictor (HR 1.025, 95% CI 1.008-1.043, p = .005). CONCLUSION: HM/TPD is an independent predictor of MACE, and for patients with HM/TPD > 38%, CTO-PCI had a lower risk of MACE compared with OMT. However, further validation is still needed through large-scale studies.

Geographic diversity in chronic total occlusion percutaneous coronary intervention: insights from the PROGRESS-CTO registry.

BACKGROUND: There is variability in clinical and lesion characteristics as well as techniques in chronic total occlusion (CTO) percutaneous coronary intervention (PCI). METHODS: We analyzed patient and lesion characteristics, techniques, and outcomes in 11 503 CTO-PCI procedures performed in North America (NA) and in the combined regions of Europe, Asia, and Africa from 2017 to 2023 as documented in the PROGRESS-CTO registry. RESULTS: Eight thousand four hundred seventy-nine (74%) procedures were performed in NA. Compared with non-NA patients, NA patients were older, with higher body mass index and higher prevalence of diabetes, hypertension, dyslipidemia, family history of coronary artery disease, prior history of PCI, coronary artery bypass graft surgery and heart failure, cerebrovascular disease, and peripheral arterial disease. Their CTOs were more complex, with higher J-CTO (2.56 ± 1.22 vs 1.81 ± 1.24; P less than .001) and PROGRESS-CTO (1.29 ± 1.01 vs 1.07 ± 0.95; P less than .001) scores, longer length, and higher prevalence of proximal cap ambiguity, blunt/no stump, moderate to severe calcification, and proximal tortuosity. Retrograde (31.0% vs 22.1%; P less than .001) and antegrade dissection and re-entry (ADR) (21.2% vs 9.2%; P less than .001) were more commonly used in NA centers, along with intravascular ultrasound (69.0% vs 10.1%; P less than .001). Procedure and fluoroscopy times were longer in NA, while contrast volume and radiation dose were lower. Technical (86.7% vs 86.8%; P > .90) and procedural (85.4% vs 85.8%; P = .70) success and in-hospital major adverse cardiovascular events (MACE) (1.9% vs 1.7%; P = .40) were similar in NA and non-NA centers. CONCLUSIONS: Compared with non-NA patients, NA patients undergoing CTO PCI have more comorbidities, higher CTO lesion complexity, are more likely to undergo treatment with retrograde and ADR, and have similar technical success and MACE.