Intracoronary imaging (ICI) was introduced over 3 decades ago to complement conventional coronary angiography, yet its widespread uptake remains limited. This paper seeks to explore the potential causes behind low ICI utilization. The concepts of acceptability, acceptance, and adoption were applied to understand at which stage individual factors influence ICI implementation. Overall, the document aims at offering a comprehensive understanding of the challenges affecting ICI adoption, laying the foundation for effective change strategies. This approach is intended to address the broader, multifaceted nature of ICI implementation, providing a starting point for broadening its integration into clinical practice.

Coronary artery disease (CAD) is the leading cause of mortality among patients with chronic kidney disease (CKD), presenting unique challenges in diagnosis and management. Advanced CKD patients often present with atypical symptoms, and conventional diagnostic and interventional approaches carry risks, including contrast-induced nephropathy and the potential need for renal replacement therapy. These risks have led to the phenomenon of “renalism,” where necessary procedures may be deferred due to concerns over renal injury. Emerging techniques, such as ultra-low contrast angiography (ULCA) and zero-contrast percutaneous coronary intervention (PCI), offer promising solutions by minimizing or eliminating contrast exposure. This review discusses the clinical presentation of CAD in CKD patients, limitations of traditional diagnostic approaches, and the challenges in managing these high-risk patients. It also provides an overview of ULCA and zero-contrast PCI techniques, which have shown both safety and feasibility even in complex cases. As these techniques continue to evolve, zero-contrast PCI holds the potential to become an essential component of revascularization strategies for high-risk CKD patients, enhancing procedural safety while maintaining therapeutic efficacy.

Coronary stent underexpansion is an important problem and limitation of percutaneous coronary intervention, adversely affecting both short- and long-term patient outcomes. Stent underexpansion occurs when a stent fails to expand adequately compared with the adjacent reference segment, resulting in inadequate luminal gain. Multiple studies suggest that stent underexpansion is associated with increased risks of in-stent restenosis, stent thrombosis, and myocardial infarction, resulting in recurrent symptoms, readmissions, repeat interventions, and increased mortality. Contributing factors for stent underexpansion include severe calcification, inadequate lesion preparation, suboptimal stent deployment, and preexisting in-stent restenosis. Calcific plaques, especially when present behind a previously implanted, underexpanded stent, pose a significant challenge for further stent optimization. These lesions are often resistant to high-pressure balloon dilatation and may require advanced techniques that carry increased risks of complications. Intravascular imaging modalities, such as intravascular ultrasound and optical coherence tomography, have emerged as essential tools in diagnosing and managing stent underexpansion. These techniques provide a more detailed evaluation of the vessel and previously implanted stent, enabling the clinician to understand the exact mechanism of stent failure, and assess plaque burden and morphology, which ultimately helps guide appropriate treatment strategies. Despite the clinical importance of stent underexpansion, there is currently no consensus on its optimal treatment, largely because of the absence of large prospective studies in this area. This comprehensive review aims to summarize the existing evidence, clinical experience, and treatment strategies for coronary stent underexpansion, with the goal of providing practical guidance to clinicians to help optimize percutaneous coronary intervention and patient outcomes.

INTRODUCTION:The super high-pressure NC balloon (OPN NC; SIS Medical AG, Winterthur, Switzerland) is increasingly used in percutaneous coronary intervention (PCI). We performed a systematic review and meta-analysis of its efficacy and safety. METHODS:A systematic review was conducted using PubMed and the Cochrane Library to identify studies using the OPN NC balloon in PCI. Procedural success, major adverse cardiac events (MACE), coronary perforation, and other complications were pooled using weighted means, confidence intervals (CI), and I² statistics for heterogeneity assessment. RESULTS:Twenty-nine studies (5 prospective including 2 randomized-controlled trials, 12 retrospective, and 12 case reports) were included in the systematic review, of which 11 (3 prospective, 8 retrospective) were included in the meta-analysis. Of the 1015 meta-analysis patients, 50.7% presented with stable angina and 21.6% with an acute coronary syndrome. Mean lesion length was 22.8 ± 13.7 mm, the prevalence of moderate or severe calcification was 93.7%, and 40.4% of lesions were in-stent. Procedural success was 95.1% (95% CI 89.3%-98.8% with significant heterogeneity: I² = 84.9%). The incidence of periprocedural MACE was 1.9% (95% CI 1.1%-2.8%, I² 86.9%), and the incidence of coronary perforation was 0.6% (95% CI 0.3%-1.5%, I² 87.2%). CONCLUSIONS:Use of the OPN NC balloon is associated with high success and acceptable complication rates. The heterogeneity of outcomes underscores the need for additional studies and standardized definitions.

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

Background: Chronic total occlusion (CTO) percutaneous coronary intervention (PCI) is associated with a considerable risk of complications, and risk stratification is of utmost importance.Aims: To assess the clinical usefulness of the recently developed PROGRESS-CTO (NCT02061436) complication risk scores in an independent cohort. Methods: Individual patient data pooled analysis of 3 registries was performed.Results: Of the 4569 patients who underwent CTO PCI, 102 (2.2%) had major adverse cardiovascular events (MACE). Patients with MACE were older (69 +/- 11 vs. 65 +/- 10, p < 0.001), more likely to have a history of prior coronary artery bypass graft surgery, and unfavorable angiographic characteristics J-CTO score (2.4 +/- 1.2 vs. 2.1 +/- 1.3, p = 0.007), including blunt stump (59% vs. 49%, p = 0.047). Technical success was lower in patients with MACE (59% vs. 86%, p < 0.001). The area under the receiver operating characteristic curve of the PROGRESS-CTO complication risk models were as follows: MACE 0.72 (95% confidence interval [CI], 0.67-0.76), mortality 0.73 (95% CI, 0.61-0.85), and pericardiocentesis 0.69 (95% CI, 0.62-0.77) in the validation dataset. The observed complication rates increased with higher PROGRESS-CTO complication scores. The PROGRESS-CTO MACE score showed good calibration in this external cohort, with MACE rates similar to the original study: 0.7% (score 0-1), 1.5% (score 2), 2.2% (score 3), 3.8% (score 4), 4.9% (score 5), 5.8% (score 6-7).Conclusion: Given the good discriminative performance, calibration, and ease of calculation, the PROGRESS-CTO complication scores could help assess the risk of complications in patients undergoing CTO PCI.

BackgroundIntravascular lithotripsy (IVL) safely and effectively modifies calcified coronary lesions during percutaneous coronary interventions (PCI). Data regarding its utility in modifying calcified left main coronary artery (LMCA) disease are limited. This study aimed to evaluate short-term outcomes of IVL-assisted LMCA PCI.MethodsThis retrospective multicenter all-comers study analyzed patients who underwent intravascular imaging-guided, IVL-assisted PCI for calcified LMCA disease. Clinical and procedural characteristics were obtained, including intravascular imaging measurements. Technical success was defined as successful stent deployment with <30% residual diameter stenosis. Major adverse cardiac events (MACE) was a composite of all-cause death, myocardial infarction, and target vessel revascularization evaluated immediately postprocedure and at 30-day follow-up.ResultsAmong 184 patients treated at 7 centers from 2019-2023, IVL-assisted LMCA PCI achieved 99.4% technical success. Calcium fracture was identified in 136/165 cases (82.4%) on post-IVL imaging. Pretreatment minimal luminal area increased significantly compared to post-PCI minimal stent area (MSA) (4.1 ± 1.3 to 9.3 ± 2.5 mm2, respectively; P < .001). There was a direct correlation between IVL balloon size and the final MSA (P = .002). In-hospital MACE was 4.4% and 30-day MACE was 8.8%. In multivariate logistic regression, presentation with troponin-positive myocardial infarction was the sole predictor of 30-day MACE.ConclusionsIVL-assisted PCI for calcified LMCA lesions was safe and resulted in high technical success rates, confirming its utility as an effective treatment in this challenging lesion subset.

Coronary artery perforation is one of the most feared and common complications of chronic total occlusion (CTO) percutaneous coronary intervention (PCI). To assess the usefulness of the recently developed PROGRESS-CTO (NCT02061436) perforation risk score in independent cohorts. Individual patient-level data pooled analysis of three registries was performed. Of the 4566 patients who underwent CTO PCI at 25 centers, 196 (4.2%) had coronary artery perforation. Patients with perforations were older (69 ± 10 vs. 65 ± 10, p  < 0.001), more likely to be women (19% vs. 13%, p  = 0.009), more likely to have a history of prior coronary artery bypass graft (34% vs. 20%, p  < 0.001), and unfavorable angiographic characteristics such as blunt stump (62% vs. 48%, p  < 0.001), proximal cap ambiguity (52% vs. 34%, p  < 0.001), and moderate-severe calcification (60% vs. 49%, p  = 0.002). Technical success was lower in patients with perforations (73% vs. 88%, p  < 0.001). The area under the receiver operating characteristic curve of the PROGRESS-CTO perforation risk model was 0.76 (95% confidence interval [CI], 0.72−0.79), with good calibration (Hosmer-Lemeshow p  = 0.97). We found that the CTO PCI perforation risk increased with higher PROGRESS-CTO perforation scores: 0.3% (score 0), 2.3% (score 1), 3.1% (score 2), 5.5% (score 3), 7.5% (score 4), 14.6% (score 5). Given the good discriminative performance, calibration, and the ease of calculation, the PROGRESS-CTO perforation score may facilitate assessment of the risk of perforation in patients undergoing CTO PCI.

BACKGROUND:Although high body mass index (BMI) is a known risk factor for the development of cardiovascular diseases, people who are overweight or obese often have better outcomes after cardiac procedures. Whether this "obesity paradox" is observed in chronic total occlusion (CTO) percutaneous coronary intervention (PCI) is unknown. Therefore, we examined the association of BMI with the outcomes of CTO-PCI in patients from the large, multicenter PROGRESS-CTO registry after stratifying patients into 3 BMI groups.

BACKGROUND:Same day discharge (SDD) following chronic total occlusion (CTO) percutaneous coronary intervention (PCI) has received limited study.METHODS:We evaluated the clinical, angiographic, and procedural characteristics of patients discharged the same day versus those kept for overnight observation in the Prospective Global Registry for the Study of Chronic Total Occlusion Intervention (PROGRESS-CTO, NCT02061436).RESULTS:Of the 7181 patients who underwent CTO PCI, 943 (13%) had SDD. The SDD rate increased from 3% in 2015 to 21% in 2022. Patients with SDD were less likely to have a history of heart failure (21% vs. 26%, p = 0.005), chronic lung disease (10% vs. 15%, p = 0.001), or anemia (12% vs. 19%, p < 0.001). Technical success (87% vs. 88%, p = 0.289) was similar, but in-hospital major adverse cardiovascular events (0.0% vs. 0.4%, p = 0.041) were lower in SDD. In multivariable logistic regression analysis, prior myocardial infarction odds ratio (OR): 0.71 (95% confidence interval [CI]: 0.59-0.87, p = 0.001), chronic lung disease OR: 0.64 (95% CI: 0.47-0.88, p = 0.006), and increasing procedure time OR: 0.93 (95% CI: 0.91-0.95, p < 0.001, per 10-min increase) were associated with overnight observation, while radial-only access OR: 2.45 (95% CI: 2.03-2.96, p < 0.001) had the strongest association with SDD. In the SDD, 2 (0.4%) of 514 patients were readmitted, due to retroperitoneal bleeding (n = 1) and ischemic stroke (n = 1).CONCLUSION:The overall frequency of SDD after CTO PCI was 13% and has been increasing over time. SDD is feasible in select patients following CTO PCI, and radial-only access had the strongest association with SDD.

Background: Balloon uncrossable lesions are defined as lesions that cannot be crossed with a balloon after successful guidewire crossing. Methods: We analyzed the association between balloon uncrossable lesions and procedural outcomes of 8671 chronic total occlusions (CTOs) percutaneous coronary interventions (PCIs) performed between 2012 and 2022 at 41 centers. Results: The prevalence of balloon uncrossable lesions was 9.2%. The mean patient age was 64.2 ± 10 years and 80% were men. Patients with balloon uncrossable lesions were older (67.3 ± 9 vs. 63.9 ± 10, p < 0.001) and more likely to have prior coronary artery bypass graft surgery (40% vs. 25%, p < 0.001) and diabetes mellitus (50% vs. 42%, p < 0.001) compared with patients who had balloon crossable lesions. In-stent restenosis (23% vs. 16%. p < 0.001), moderate/severe calcification (68% vs. 40%, p < 0.001), and moderate/severe proximal vessel tortuosity (36% vs. 25%, p < 0.001) were more common in balloon uncrossable lesions. Procedure time (132 (90, 197) vs. 109 (71, 160) min, p < 0.001) was longer and the air kerma radiation dose (2.55 (1.41, 4.23) vs. 1.97 (1.10, 3.40) min, p < 0.001) was higher in balloon uncrossable lesions, while these lesions displayed lower technical (91% vs. 99%, p < 0.001) and procedural (88% vs. 96%, p < 0.001) success rates and higher major adverse cardiac event (MACE) rates (3.14% vs. 1.49%, p < 0.001). Several techniques were required for balloon uncrossable lesions. Conclusion: In a contemporary, multicenter registry, 9.2% of the successfully crossed CTOs were initially balloon uncrossable. Balloon uncrossable lesions exhibited lower technical and procedural success rates and a higher risk of complications compared with balloon crossable lesions.

Use of radial access for chronic total occlusion (CTO) percutaneous coronary intervention (PCI) has been increasing. We examined the clinical characteristics and procedural outcomes of patients who underwent CTO PCI with radial versus femoral access in the Prospective Global Registry for the Study of CTO Intervention (PROGRESS-CTO, NCT02061436). Of 10,954 patients who underwent CTO PCI at 55 centers in 7 countries between 2012 and 2022, 2578 (24%) had a radial only approach. Patients who underwent radial only access were younger (63 ± 10 vs. 65 ± 10, years, p  < 0.001), more likely to be men (84% vs. 81%, p  = 0.001), and had significantly lower prevalence of comorbidities compared with the femoral access group including diabetes mellitus (39% vs. 45%, p  < 0.001) and coronary artery bypass graft surgery (57% vs. 64%, p  < 0.001). In addition, radial only cases had lower angiographic complexity with lower J-CTO and PROGRESS-CTO scores. After adjusting for potential confounders, radial only access was associated with lower risk of access site complications (odds ratio [OR]: 0.45, 95% confidence interval [CI]: 0.22–0.91), similar technical success (OR: 0.87, 95% CI: 0.74–1.04) and major adverse cardiovascular events (MACE) (OR: 0.65, 95% CI: 0.40–1.07), compared with the femoral access group. Radial only access was used in 24% of CTO PCIs and was associated with lower access site complications, and similar technical success and MACE as compared with the femoral access group.

Introduction: Use of radial access for chronic total occlusion (CTO) percutaneous coronary intervention (PCI) has been increasing. Methods: We examined the clinical characteristics and procedural outcomes of patients who underwent CTO PCI with radial versus femoral access in the Prospective Global Registry for the Study of CTO Intervention (PROGRESS-CTO, NCT02061436). Results: Of 10,954 patients who underwent CTO PCI at 55 centers in 7 countries between 2012 and 2022, 2,578 (24%) had a radial-only approach. Patients who underwent radial-only access were younger (63 ± 10 vs. 65 ± 10, years, p<0.001), more likely to be men (84% vs. 81%, p=0.001), and had a significantly lower prevalence of comorbidities compared with the femoral group, including diabetes mellitus (39% vs. 45%, p<0.001) and coronary artery bypass graft surgery (57% vs. 64%, p<0.001). In addition, radial-only cases had lower angiographic complexity with lower J-CTO (2.0 ± 1.3 vs. 2.5 ± 1.2, p<0.001) and PROGRESS-CTO (1.2 ± 1.0 vs. 1.3 ± 1.0, p<0.001) scores. After adjusting for potential confounders, radial-only access was associated with a lower risk of access site complications (odds ratio [OR]: 0.45, 95% confidence interval [CI], 0.22-0.91), similar technical success (OR: 0.87, 95% CI, 0.74-1.04) and major adverse cardiovascular events (MACE) (OR: 0.65, 95% CI, 0.40-1.07), compared with the femoral access group (Figure 1). Conclusions: Radial-only access was used in 24% of CTO PCIs and was associated with lower access site complications, and similar technical success and MACE compared with the femoral access group.

An upfront (primary) retrograde strategy is often used in complex chronic total occlusion (CTO) percutaneous coronary intervention (PCI).

BACKGROUND Chronic total occlusion (CTO) percutaneous coronary intervention (PCI) is associated with increased risk of periprocedural complications. Estimating the risk of complications facilitates risk-benefit assessment and procedural planning. OBJECTIVES This study sought to develop risk scores for in-hospital major adverse cardiovascular events (MACE), mortality, pericardiocentesis, and acute myocardial infarction (MI) in patients undergoing CTO PCI. METHODS The study analyzed the PROGRESS-CTO (Prospective Global Registry for the Study of Chronic Total Occlu-sion Intervention; NCT02061436) and created risk scores for MACE, mortality, pericardiocentesis, and acute MI. Logistic regression prediction modeling was used to identify independently associated variables, and models were internally validated with bootstrapping. RESULTS The incidence of periprocedural complications among 10,480 CTO PCIs was as follows: MACE 215 (2.05%), mortality 47 (0.45%), pericardiocentesis 83 (1.08%), and acute MI 66 (0.63%). The final model for MACE included >= 65 years of age (1 point), moderate-severe calcification (1 point), blunt stump (1 point), antegrade dissection and re-entry (ADR) (1 point), female (2 points), and retrograde (2 points); the final model for mortality included >= 65 years of age (1 point), left ventricular ejection fraction #45% (1 point), moderate-severe calcification (1 point), ADR (1 point), and retrograde (1 point); the final model for pericardiocentesis included >= 65 years of age (1 point), female (1 point), moderate-severe calcification (1 point), ADR (1 point), and retrograde (2 points); the final model for acute MI included prior coronary artery bypass graft surgery (1 point), atrial fibrillation (1 point), and blunt stump (1 point). The C-statistics of the models were 0.74, 0.80, 0.78, 0.72 for MACE, mortality, pericardiocentesis, and acute MI, respectively. CONCLUSIONS The PROGRESS-CTO complication risk scores can facilitate estimation of the periprocedural compli-cation risk in patients undergoing CTO PCI. (C) 2022 by the American College of Cardiology Foundation.

BACKGROUND:The prevalence and outcomes of patients who presented with an acute coronary syndrome (ACS) and underwent chronic total occlusion (CTO) percutaneous coronary intervention (PCI) have received limited study.METHODS:We examined the clinical characteristics and procedural outcomes of ACS patients who underwent CTO-PCI in the Prospective Global Registry for the Study of CTO Intervention (PROGRESS-CTO; NCT02061436).RESULTS:Of the 8826 patients who underwent CTO-PCI between 2012 and 2022 at 38 centers, 558 (6.3%) presented with ACS. ACS presentation was with non-ST-segment elevation myocardial infarction (MI) in 54%, unstable angina in 33%, and ST-segment elevation MI in 6.5%. ACS patients were older (66 ± 11 years vs 64 ± 10 years; P<.001) and had higher prevalence of comorbidities such as diabetes mellitus (48% vs 42%; P=.02), prior MI (52% vs 45%; P<.01), and lower left ventricular ejection fraction (49 ± 14% vs 51 ± 13%; P<.01). While the PROGRESS-CTO score (1.4 ± 1.0 vs 1.2 ± 1.0; P<.001) was higher in the ACS group, the J-CTO score was comparable (2.3 ± 1.2 vs 2.4 ± 1.3; P=.68). Technical success (88% vs 86%; P=.12) and the incidence of in-hospital major adverse cardiovascular event (MACE) (0.9% vs 2.1%; P=.06) and adverse events at 3-month follow-up (3.4% vs 7.2%; Kaplan-Meier log-rank P=.16) were similar between ACS and non-ACS patients, respectively.CONCLUSION:Approximately 6% of patients who underwent CTO-PCI presented with an ACS. Technical success, in-hospital MACE, and the incidence of adverse events up to 3 months were similar between patients who presented with vs without an ACS.

The relationship between left ventricular ejection fraction (LVEF) and the success and safety of coronary chronic total occlusion (CTO) percutaneous coronary intervention (PCI) has received limited study.

The use of mechanical circulatory support (MCS) in chronic total occlusion (CTO) percutaneous coronary intervention (PCI) has received limited study. We analyzed the clinical and angiographic characteristics, and procedural outcomes of 7,171 CTO PCIs performed between 2012 and 2021 at 35 international centers. Mean age was 64.5 ± 10 years, mean left ventricular ejection fraction was 50 ± 13%. MCS was used in 4.5%, prophylactically in 78.7%, and urgently in 21.3%. The most common type of MCS overall was Impella CP (Abiomed) (55.5%), followed by intra-aortic balloon pump (14.8%) and TandemHeart (LivaNova Inc.) (10.0%). Prophylactic MCS patients were more likely to have diabetes mellitus (55% vs 42%, p <0.001) and had more complex lesions compared with cases without prophylactic MCS (Japan-CTO score: 2.80 ± 1.22 vs 2.39 ± 1.27, p <0.001). Cases with prophylactic MCS had similar technical (86% vs 87%, p = 0.643) but lower procedural (80% vs 86%, p = 0.028) success rates and higher rates of periprocedural major cardiac adverse events compared with no prophylactic MCS use (6.55% vs 1.68%, p <0.001). Urgent MCS use was associated with lower technical (68% vs 87%, p <0.001) and procedural (39% vs 86%, p <0.001) success rates and higher major cardiac adverse events compared with no-MCS use (32.26% vs 1.68%, p <0.001). The differences persisted in multivariable analyses. In summary, in this contemporary multicenter registry, MCS was used in 4.5% of CTO PCIs, mostly prophylactically (78.7%). Elective MCS cases had similar technical success but a higher risk of complications. Urgent MCS cases had lower technical and procedural success and higher periprocedural major complication rates.