Global Consensus Recommendations on Improving the Safety of Chronic Total Occlusion Interventions.

Safety is of critical importance to chronic total occlusion (CTO) percutaneous coronary intervention (PCI). This global consensus statement provides guidance on how to optimise the safety of CTO) PCI, addressing the following 12 areas: 1. Set-up for safe CTO PCI; 2. Guide catheter--associated vessel injuries; 3. Hydraulic dissection, extraplaque haematoma expansion, and aortic dissections; 4. Haemodynamic collapse during CTO PCI; 5. Side branch occlusion; 6. Perforations; 7. Equipment entrapment; 8. Vascular access considerations; 9. Contrast-induced acute kidney injury; 10. Radiation injury; 11 When to stop; and, 12. Proctorship. This statement complements the global CTO crossing algorithm; by advising how to prevent and deal with complications, this statement aims to facilitate clinical practice, research, and education relating to CTO PCI.

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.

Ranolazine in chronic total occlusion percutaneous coronary intervention.

Ranolazine is an anti-anginal medication given to patients with chronic angina and persistent symptoms despite medical therapy. We examined 11 491 chronic total occlusion (CTO) percutaneous coronary interventions (PCI) that were performed at 41 US and non-US centers between 2012 and 2023 in the PROGRESS-CTO Registry. Patients on ranolazine at baseline had more comorbidities, more complex lesions, lower procedural and technical success (based on univariable but not multivariable analysis), and higher incidence of major adverse cardiac events (MACE) (on both univariable and multivariable analysis).

Exploring the Role of ChatGPT in Cardiology: A Systematic Review of the Current Literature.

Chat Generative Pre-Trained Transformer (ChatGPT) is a chatbot based on a large language model that has gained public interest since its release in November 2022. This systematic review examines the current literature on the potential applications of ChatGPT in cardiology. A systematic literature search was conducted to retrieve all publications on ChatGPT in PubMed, Scopus, MedRxiv, and the Cochrane Library published on or before September 30, 2023. Search terms relating to ChatGPT and cardiology were used. Publications without relevance to ChatGPT and cardiology were excluded. The included publications were divided into cohorts. Cohort A examined ChatGPT's role in improving patient health literacy. Cohort B explored ChatGPT's role in clinical care. Cohort C examined ChatGPT's role in future literature and research. Cohort D included case reports that used ChatGPT. A total of 115 publications were found across all databases. Twenty-four publications met the inclusion criteria and were included in the review. Cohort A-C included a total of 14 records comprised of editorials/letters to the editor (29%), research letters/correspondence (21%), review papers (21%), observational studies (7%), research studies (7%), and short reports (7%). Cohort D included 10 case reports. No relevant systematic literature reviews, meta-analyses, or randomized controlled trials were identified in the search.  Based on this review of the literature, ChatGPT has the potential to enhance patient education, support clinicians providing clinical care, and enhance the development of future literature. However, further studies are needed to understand the potential applications of ChatGPT in cardiology and to address ethical concerns regarding the delivery of medical advice and the authoring of manuscripts.

Interventional cardiologists' perspectives and knowledge towards artificial intelligence.

BACKGROUND: Artificial intelligence (AI) is increasingly utilized in interventional cardiology (IC) and holds the potential to revolutionize the field. METHODS: We conducted a global, web-based, anonymous survey of IC fellows and attendings to assess the knowledge and perceptions of interventional cardiologists regarding AI use in IC. RESULTS: A total of 521 interventional cardiologists participated in the survey. The median age range of participants was 36 to 45 years, most (51.5%) practice in the United States, and 7.5% were women. Most (84.7%) could explain well or somehow knew what AI is about, and 63.7% were optimistic/very optimistic about AI in IC. However, 73.5% believed that physicians know too little about AI to use it on patients and most (46.1%) agreed that training will be necessary. Only 22.1% were currently implementing AI in their personal clinical practice, while 60.6% estimated implementation of AI in their practice the next 5 years. Most agreed that AI will increase diagnostic efficiency, diagnostic accuracy, treatment selection, and healthcare expenditure, and decrease medical errors. The most tried AI-powered tools were image analysis (57.3%), ECG analysis (61.7%), and AI-powered algorithms (45.9%). Interventional cardiologists practicing in academic hospitals were more likely to have AI tools currently implemented in their clinical practice and to use them, women had a higher likelihood of expressing concerns regarding AI, and younger interventional cardiologists were more optimistic about AI integration in IC. CONCLUSIONS: Our survey suggests a positive attitude of interventional cardiologists regarding AI implementation in the field of IC.

Validation of the BCIS CHIP Score in chronic total occlusion percutaneous coronary intervention.

BACKGROUND: The complex high-risk indicated percutaneous coronary intervention (CHIP) score is a tool developed using the British Cardiovascular Intervention Society (BCIS) database to define CHIP cases and predict in-hospital major adverse cardiac or cerebrovascular events (MACCE). AIM: To assess the validity of the CHIP score in chronic total occlusion (CTO) percutaneous coronary intervention (PCI). METHODS: We evaluated the performance of the CHIP score on 8341 CTO PCIs from the Prospective Global Registry for the Study of Chronic Total Occlusion Intervention (PROGRESS-CTO) performed at 44 centers between 2012 and 2023. RESULTS: In our cohort, 7.8% (n = 647) of patients had a CHIP score of 0, 50.2% (n = 4192) had a CHIP score of 1-2, 26.2% (n = 2187) had a CHIP score of 3-4, 11.7% (n = 972) had a CHIP score of 5-6, 3.3% (n = 276) had a CHIP score of 7-8, and 0.8% (n = 67) had a CHIP score of 9+. The incidence of MACCE for a CHIP score of 0 was 0.6%, reaching as high as 8.7% for a CHIP score of 9+, confirming that a higher CHIP score is associated with a higher risk of MACCE. The estimated increase in the risk of MACCE per one score unit increase was 100% (95% confidence interval [CI]: 65%-141%). The AUC of the CHIP score model for predicting MACCE in our cohort was 0.63 (95% CI: 0.58-0.67). There was a positive correlation between the CHIP score and the PROGRESS-CTO MACE score (Spearman's correlation: 0.37; 95% CI: 0.35-0.39; p < 0.001). CONCLUSIONS: The CHIP score has modest predictive capacity for MACCE in CTO PCI.

Impact of Coronary Microvascular Dysfunction on Functional Left Ventricular Remodeling and Diastolic Dysfunction.

BACKGROUND: Coronary microvascular dysfunction (CMD) is a common complication of ST-segment-elevation myocardial infarction (STEMI) and can lead to adverse cardiovascular events. Whether CMD after STEMI is associated with functional left ventricular remodeling (FLVR) and diastolic dysfunction, has not been investigated. METHODS AND RESULTS: This is a nonrandomized, observational, prospective study of patients with STEMI with multivessel disease. Coronary flow reserve and index of microcirculatory resistance of the culprit vessel were measured at 3 months post-STEMI. CMD was defined as index of microcirculatory resistance ≥25 or coronary flow reserve <2.0 with a normal fractional flow reserve. We examined the association between CMD, LV diastolic dysfunction, FLVR, and major adverse cardiac events at 12-month follow-up. A total of 210 patients were enrolled; 59.5% were men, with a median age of 65 (interquartile range, 58-76) years. At 3-month follow-up, 57 patients (27.14%) exhibited CMD. After 12 months, when compared with patients without CMD, patients with CMD had poorer LV systolic function recovery (-10.00% versus 8.00%; P<0.001), higher prevalence of grade 2 LV diastolic dysfunction (73.08% versus 1.32%; P<0.001), higher prevalence of group 3 or 4 FLVR (11.32% versus 7.28% and 22.64% versus 1.99%, respectively; P<0.001), and higher incidence of major adverse cardiac events (50.9% versus 9.8%; P<0.001). Index of microcirculatory resistance was independently associated with LV diastolic dysfunction and adverse FLVR. CONCLUSIONS: CMD is present in ≈1 of 4 patients with STEMI during follow-up. Patients with CMD have a higher prevalence of LV diastolic dysfunction, adverse FLVR, and major adverse cardiac events at 12 months compared with those without CMD. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique Identifier: NCT05406297.

Retrograde chronic total occlusion percutaneous coronary intervention via ipsilateral collaterals.

BACKGROUND: There is limited data on retrograde chronic total occlusion (CTO) percutaneous coronary intervention (PCI) via ipsilateral epicardial collaterals (IEC). AIMS: To compare the clinical and angiographic characteristics, and outcomes of retrograde CTO PCI via IEC versus other collaterals in a large multicenter registry. METHODS: Observational cohort study from the Prospective Global registry for the study of Chronic Total Occlusion Intervention (PROGRESS-CTO). RESULTS: Of 4466 retrograde cases performed between 2012 and 2023, crossing through IEC was attempted in 191 (4.3%) cases with 50% wiring success. The most common target vessel in the IEC group was the left circumflex (50%), in comparison to other retrograde cases, where the right coronary artery was most common (70%). The Japanese CTO score was similar between the two groups (3.13 ± 1.23 vs. 3.06 ± 1.06, p = 0.456); however, the IEC group had a higher Prospective Global Registry for the Study of Chronic Total Occlusion Intervention (PROGRESS-CTO) score (1.95 ± 1.02 vs. 1.27 ± 0.92, p < 0.0001). The most used IEC guidewire was the SUOH 03 (39%), and the most frequently used microcatheter was the Caravel (43%). Dual injection was less common in IEC cases (66% vs. 89%, p < 0.0001). Technical (76% vs. 79%, p = 0.317) and procedural success rates (74% vs. 79%, p = 0.281) were not different between the two groups. However, IEC cases had a higher procedural complications rate (25.8% vs. 16.4%, p = 0.0008), including perforations (17.3% vs. 9.0%, p = 0.0001), pericardiocentesis (3.1% vs. 1.2%, p = 0.018), and dissection/thrombus of the donor vessel (3.7% vs. 1.2%, p = 0.002). CONCLUSION: The use of IEC for retrograde CTO PCI was associated with similar technical and procedural success rates when compared with other retrograde cases, but higher incidence of periprocedural complications.

Update on chronic total occlusion percutaneous coronary intervention.

Chronic total occlusion (CTO) percutaneous coronary intervention (PCI) continues to evolve. This review summarizes recent publications categorized by outcomes, techniques, complications, and ongoing studies in this rapidly growing area.

Racial disparities in chronic total occlusion percutaneous coronary interventions: insights from the PROGRESS-CTO registry.

OBJECTIVES: There is limited data on race and outcomes of chronic total occlusion (CTO) percutaneous coronary intervention (PCI). The authors sought to evaluate CTO PCI techniques and outcomes in different racial groups. METHODS: We examined the baseline characteristics and procedural outcomes of 11 806 CTO PCIs performed at 44 US and non-US centers between 2012 and March 2023. In-hospital major adverse cardiac events (MACE) included death, myocardial infarction, repeat target-vessel revascularization, pericardiocentesis, cardiac surgery, and stroke prior to discharge. RESULTS: The most common racial group was White (84.5%), followed by Black (5.7%), "Other" (3.9%), Hispanic (2.9%), Asian (2.4%), and Native American (0.7%). There were significant differences in the baseline characteristics between different racial groups. When compared with non-White patients, the retrograde approach and antegrade dissection re-entry were more likely to be the successful crossing strategies in White patients without any significant differences in technical success (86.4% vs 86.4%; P = .93), procedural success (84.8% vs 85.0%; P = .79), and in-hospital MACE (2.0% vs 1.5%; P = .15) between the 2 groups. The technical success rate was significantly higher in the "Other" racial group (91.0% vs 86.4% in White, 86.9% in Asian, 84.5% in Black, 84.5% in Hispanic, and 83.3% in Native American; P = .03) without any significant differences in procedural success or in-hospital MACE rates between the groups. CONCLUSIONS: Despite differences in baseline characteristics and procedural techniques, the procedural success and in-hospital MACE of CTO PCI were not significantly different between most racial groups.

Emergency coronary artery bypass surgery after chronic total occlusion percutaneous coronary intervention: Insights from the PROGRESS-CTO registry.

BACKGROUND: Emergency coronary artery bypass surgery (eCABG) is a serious complication of chronic total occlusion (CTO) percutaneous coronary artery intervention (PCI). METHODS: We examined the incidence and outcomes eCABG among 14,512 CTO PCIs performed between 2012 and 2023 in a large multicenter registry. RESULTS: The incidence of eCABG was 0.12% (n = 17). Mean age was 68 ± 6 years and 69% of the patients were men. The most common reason for eCABG was coronary perforation (70.6%). eCABG patients had larger target vessel diameter (3.36 ± 0.50 vs. 2.90 ± 0.52; p = 0.003), were more likely to have moderate/severe calcification (85.7% vs. 45.8%; p = 0.006), side branch at the proximal cap (91.7% vs. 55.4%; p = 0.025), and balloon undilatable lesions (50% vs. 7.4%; p = 0.001) and to have undergone retrograde crossing (64.7% vs. 30.8%, p = 0.006). eCABG cases had lower technical (35.3% vs. 86.7%; p < 0.001) and procedural (35.3% vs. 86.7%; p < 0.001) success and higher in-hospital mortality (35.3% vs. 0.4%; p < 0.001), coronary perforation (70.6% vs. 4.6%; p < 0.001), pericardiocentesis (47.1% vs. 0.8%; p < 0.001), and major bleeding (11.8% vs. 0.5%; p < 0.001). CONCLUSIONS: The incidence of eCABG after CTO PCI was 0.12% and associated with high in-hospital mortality (35%). Coronary perforation was the most common reason for eCABG.

Guide catheter extension use are associated with higher procedural success in chronic total occlusion percutaneous coronary interventions.

BACKGROUND: Guide catheter extensions (GCEs) increase support and facilitate equipment delivery, but aggressive instrumentation may be associated with a higher risk of complications. AIM: Our aim was to assess the impact of GCEs on procedural success and complications in patients submitted to chronic total occlusion (CTO) percutaneous coronary intervention (PCI). METHODS: We analyzed data from the multicenter LATAM CTO Registry. Procedural success was defined as <30% residual stenosis and TIMI 3 distal flow. Major adverse cardiac and cerebrovascular events (MACCE) was defined as the composite of all-cause death, myocardial infarction, target vessel revascularization, and stroke. Propensity score matching (PSM) was used to compare outcomes with and without GCE use. RESULTS: From August 2010 to August 2021, 3049 patients were included. GCEs were used in 438 patients (14.5%). In unadjusted analysis, patients in the GCE group were older and had more comorbidities. The median J-CTO score and its components were higher in the GCE group. After PSM, procedural success was higher with GCE use (87.7% vs. 80.5%, p = 0.007). The incidence of coronary perforation (odds ratio [OR]: 1.46, 95% confidence interval [CI]: 0.78-2.71, p = 0.230), bleeding (OR: 1.99, 95% CI: 0.41-2.41, p = 0.986), in-hospital death (OR: 1.39, 95% CI: 0.54-3.62, p = 0.495) and MACCE (OR: 1.07, 95% CI: 0.52-2.19, p = 0.850) were similar in both groups. CONCLUSION: In a contemporary, multicenter cohort of patients undergoing CTO PCI, GCEs were used in older patients, with more comorbidities and complex anatomy. After PSM, GCE use was associated with higher procedural success, and similar incidence of adverse outcomes.

Self-Apposing Stents in Coronary Chronic Total Occlusions: A Pilot Study.

OBJECTIVES: This pilot study assessed the 12-month angiographic and clinical outcomes of self-apposing (SA) stents in patients undergoing chronic total occlusion (CTO) percutaneous coronary intervention (PCI). BACKGROUND: Self-apposing (SA) stents may decrease incomplete strut apposition and stent strut coverage that are common after CTO PCI. METHODS: We compared 20 patients who underwent CTO PCI using SA drug-eluting stents (DESs) with 20 matched control patients who underwent CTO PCI using balloon-expandable (BE)-DESs. All patients were followed up clinically for 12 months and had coronary angiography with optical coherence tomography at the end of the follow-up period. The primary end points were stent strut malapposition and strut coverage. The secondary end point was composite major adverse cardiovascular events (MACEs) at 12 months. RESULTS: Both groups had high prevalence of diabetes mellitus, and most of the treated lesions were complex, with 62% having a J-CTO score of ≥3. All CTO PCI techniques were allowed for recanalisation, and 75% of the procedures were guided by intravascular ultrasound. At 12 months, the SA-DES group had fewer malapposed struts (0% [interquartile range (IQR) 0%-0%] vs 4.5% [IQR 0%-20%]; p<0.001) and uncovered struts (0.08% [IQR 0%-1.6%] vs 8.2% [IQR 0%-16%]; p<0.001). However, they showed significantly higher rates of MACEs due to clinically-driven target lesion revascularisation (45% vs 15%; p=0.038). CONCLUSIONS: In this pilot study, compared with conventional BE-DESs, SA-DESs used in CTO PCI were associated with fewer malapposed and uncovered stent struts but also with significantly higher rates of in-stent restenosis and MACEs, mainly caused by clinically driven target lesion revascularisation.

Use of plaque modification microcatheters during percutaneous coronary interventions for chronic total occlusion: insights from the PROGRESS-CTO Registry.

Plaque modification microcatheters (PM) (Tornus [Asahi] and Turnpike Gold [Teleflex]) are devices that are mainly used to modify the cap or lesion and maintain good support in chronic total occlusion (CTO) percutaneous coronary artery intervention (PCI). We evaluated the frequency of use and outcomes of plaque modification microcatheters in an international multicenter registry. Plaque modification microcatheters were utilized in 242 cases (1.6%: Tornus in 51% and Turnpike Gold in 49%) with decreasing frequency over time (P-for-trend: 0.007 and 0.035, respectively). Technical and procedural success and the incidence of major cardiac adverse events were similar with Tornus and Turnpike Gold use. PM are infrequently utilized in CTO-PCI and are associated with high success and acceptable complication rates.

Early vs. delayed mechanical circulatory support in patients with acute myocardial infarction and cardiogenic shock.

AIMS: Despite increased temporary mechanical circulatory support (tMCS) utilization for acute myocardial infarction complicated by cardiogenic shock (AMI-CS), data regarding efficacy and optimal timing for tMCS support are limited. This study aimed to describe outcomes based on tMCS timing in AMI-CS and to identify predictors of 30-day mortality and readmission. METHODS AND RESULTS: Patients with AMI-CS identified in the National Readmissions Database were grouped according to the use of tMCS and early (<24 h) vs. delayed (≥24 h) tMCS. The correlation between tMCS timing and inpatient outcomes was evaluated using linear regression. Multivariate logistic regression was used to identify variables associated with 30-day mortality and readmission. Of 294 839 patients with AMI-CS, 109 148 patients were supported with tMCS (8067 veno-arterial extracorporeal membrane oxygenation, 33 577 Impella, and 79 161 intra-aortic balloon pump). Of patients requiring tMCS, patients who received early tMCS (n = 79 906) had shorter lengths of stay (7 vs. 15 days, P < 0.001) and lower rates of ischaemic and bleeding complications than those with delayed tMCS (n = 32 241). Patients requiring tMCS had higher in-hospital mortality [odds ratio (95% confidence interval)] [1.7 (1.7-1.8), P < 0.001]. Among patients requiring tMCS, early support was associated with fewer complications, lower mortality [0.90 (0.85-0.94), P < 0.001], and fewer 30-day readmissions [0.91 (0.85-0.97), P = 0.005] compared with patients with delayed tMCS. CONCLUSION: Among patients receiving tMCS for AMI-CS, early tMCS was associated with fewer complications, shorter lengths of stay, lower hospital costs, and fewer deaths and readmissions at 30 days.

Predictors of successful primary antegrade wiring in chronic total occlusion percutaneous coronary intervention.

BACKGROUND: Antegrade wiring is the most commonly used chronic total occlusion (CTO) crossing technique. METHODS: Using data from the PROGRESS CTO registry (Prospective Global Registry for the Study of Chronic Total Occlusion Intervention; Clinicaltrials.gov identifier: NCT02061436), we examined the clinical and angiographic characteristics and procedural outcomes of CTO percutaneous coronary interventions (PCIs) performed using a primary antegrade wiring strategy. RESULTS: Of the 13 563 CTO PCIs performed at 46 centers between 2012 and 2023, a primary antegrade wiring strategy was used in 11 332 (83.6%). Upon multivariable logistic regression analysis, proximal cap ambiguity (odds ratio [OR]: 0.52; 95% CI, 0.46-0.59), side branch at the proximal cap (OR: 0.85; 95% CI, 0.77-0.95), blunt/no stump (OR: 0.52; 95% CI: 0.47-0.59), increasing lesion length (OR [per 10 mm increase]: 0.79; 95% CI, 0.76-0.81), moderate to severe calcification (OR: 0.73; 95% CI, 0.66-0.81), moderate to severe proximal tortuosity (OR: 0.67; 95% CI, 0.59-0.75), bifurcation at the distal cap (OR: 0.66; 95% CI, 0.59-0.73), left anterior descending artery CTO (OR [vs right coronary artery]: 1.44; 95% CI, 1.28-1.62) and left circumflex CTO (OR [vs right coronary artery]: 1.22; 95% CI, 1.07-1.40), non-in-stent restenosis lesion (OR: 0.56; 95% CI, 0.49-0.65), and good distal landing zone (OR: 1.18; 95% CI, 1.06-1.32) were independently associated with primary antegrade wiring crossing success. CONCLUSIONS: The use of antegrade wiring as the initial strategy was high (83.6%) in our registry. We identified several parameters associated with primary antegrade wiring success.

Iso-osmolar vs low-osmolar contrast agents for coronary optical coherence tomography: a blinded prospective randomized controlled study.

BACKGROUND: The impact of contrast type on coronary optical coherence tomography (OCT) imaging has received limited research. METHODS: We conducted a blinded, prospective, single-center, randomized, controlled crossover study comparing iso-osmolar contrast media (IOCM) with low-osmolar contrast media (LOCM) in patients undergoing clinically indicated coronary OCT imaging. Patients were randomly assigned to undergo OCT imaging with either IOCM or LOCM as the initial contrast medium. Following a washout period, a second run of OCT imaging of the same coronary vessel was performed using the other contrast medium. RESULTS: A total of 62 patients were randomized to IOCM first (n = 31) or LOCM first (n = 31). Mean patient age was 65.9 ± 11.2 years and 74.2% were male, with high prevalence of dyslipidemia (82.3%) and prior myocardial infarction (41.9%). Percutaneous coronary intervention was performed in 60 cases (96.8%) and the left anterior descending artery was the most common target vessel (53.3%). The contrast volume used for OCT imaging was similar for IOCM and LOCM (8.0 [6.9, 9.0] mL vs 8.0 [6.7, 9.0] mL; P = .89), as was the length of clear OCT images (70.0 [62.8, 74.0] mm for IOCM vs 70.0 [64.0, 74.0] mm for LOCM; P = .65). Electrocardiographic changes were observed in 11 runs with IOCM (ventricular repolarization changes in 9 runs and premature ventricular contractions [PVCs] in 2 runs) vs 12 runs with LOCM (ventricular repolarization changes in 9 runs and PVCs in 3 runs). CONCLUSIONS: The use of IOCM in coronary OCT is associated with similar contrast volume and clear imaging length when compared with LOCM.