Search

Background: Quantitative coronary angiography (QCA) typically employs traditional edge detection algorithms that often require manual correction. This has important implications for the accuracy of downstream 3D coronary reconstructions and computed haemodynamic indices (e.g. angiography-derived fractional flow reserve). We developed AngioPy, a deep-learning model for coronary segmentation that employs user-defined ground-truth points to boost performance and minimise manual correction. We compared its performance without correction with an established QCA system., Methods: Deep learning models integrating user-defined ground-truth points were developed using 2455 images from the Fractional Flow Reserve versus Angiography for Multivessel Evaluation 2 (FAME 2) study. External validation was performed on a dataset of 580 images. Vessel dimensions from 203 images with mild/moderate stenoses segmented by AngioPy (without correction) and an established QCA system (Medis QFR®) were compared (609 diameters)., Results: The top-performing model had an average F1 score of 0.927 (pixel accuracy 0.998, precision 0.925, sensitivity 0.930, specificity 0.999) with 99.2 % of masks exhibiting an F1 score > 0.8. Similar results were seen with external validation (F1 score 0.924, pixel accuracy 0.997, precision 0.921, sensitivity 0.929, specificity 0.999). Vessel dimensions from AngioPy exhibited excellent agreement with QCA (r = 0.96 [95 % CI 0.95-0.96], p < 0.001; mean difference - 0.18 mm [limits of agreement (LOA): -0.84 to 0.49]), including the minimal luminal diameter (r = 0.93 [95 % CI 0.91-0.95], p < 0.001; mean difference - 0.06 mm [LOA: -0.70 to 0.59])., Conclusion: AngioPy, an open-source tool, performs rapid and accurate coronary segmentation without the need for manual correction. It has the potential to increase the accuracy and efficiency of QCA., Competing Interests: Declaration of competing interest BDB reports receiving consultancy fees from Boston Scientific and Abbott Vascular, research grants from Coroventis Research, Pie Medical Imaging, CathWorks, Boston Scientific, Siemens, HeartFlow Inc., and Abbott Vascular, and owning equity in Siemens, GE, Philips, HeartFlow Inc., Edwards Life Sciences, Bayer, Sanofi, Celyad. All the other authors have nothing to disclose. The following are the supplementary data related to this article. Supplementary data to this article can be found online at https://doi.org/10.1016/j.ijcard.2024.132598., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Background: Vulnerable plaque presents prognostic implications in addition to functional significance., Objectives: The aim of this study was to identify relevant features of vulnerable plaque in functionally significant lesions., Methods: In this multicenter, prospective study conducted across 5 countries, including patients who had invasive fractional flow reserve (FFR) ≤0.80, a total of 95 patients with available pullback pressure gradient (PPG) and plaque analysis on coronary computed tomographic angiography and optical coherence tomography were analyzed. Vulnerable plaque was defined as the presence of plaque rupture or thin-cap fibroatheroma on optical coherence tomography. Among the 25 clinical characteristics, invasive angiographic findings, physiological indexes, and coronary computed tomographic angiographic findings, significant predictors of vulnerable plaque were identified., Results: Mean percentage diameter stenosis, FFR, and PPG were 77.8% ± 14.6%, 0.66 ± 0.13, and 0.65 ± 0.13, respectively. Vulnerable plaque was present in 53 lesions (55.8%). PPG and FFR were identified as significant predictors of vulnerable plaque (P < 0.05 for all). PPG >0.65 and FFR ≤0.70 were significantly related to a higher probability of vulnerable plaque after adjustment for each other (OR: 6.75 [95% CI: 2.39-19.1]; P < 0.001] for PPG >0.65; OR: 4.61 [95% CI: 1.66-12.8]; P = 0.003 for FFR ≤0.70). When categorizing lesions according to combined PPG >0.65 and FFR ≤0.70, the prevalence of vulnerable plaque was 20.0%, 57.1%, 66.7%, and 88.2% in the order of PPG ≤0.65 and FFR >0.70, PPG ≤0.65 and FFR ≤0.70, PPG >0.65 and FFR >0.70, and PPG >0.65 and FFR ≤0.70 (P for trend < 0.001), respectively., Conclusions: Among low-FFR lesions, the presence of vulnerable plaque can be predicted by PPG combined with FFR without additional anatomical or plaque characteristics. (Precise Percutaneous Coronary Intervention Plan [P3] Study; NCT03782688)., Competing Interests: Funding Support and Author Disclosures This study received funding from HeartFlow and was also supported by grants from the Patient-Centered Clinical Research Coordinating Center (HI19C0481 and HC19C0305) funded by the Ministry of Health and Welfare and from the Ministry of Food and Drug Safety (RS-2023-00215667), Republic of Korea. Dr Mizukami has received consulting fees from Zeon Medical and HeartFlow; and has received speaker fees from Abbott Vascular. Dr Leipsic is a consultant for and holds stock options in Circle CVI and HeartFlow; has received a research grant from GE; and has received modest speaker fees from GE and Philips. Drs Sonck and Munhoz have received research grants provided by the Cardiopath PhD program. Dr Nørgaard has received unrestricted institutional research grants from Siemens and HeartFlow. Dr Otake has received research grants from Abbott Vascular; and has received speaker fees from HeartFlow and Abbott Vascular. Dr Ko has received consulting fees from Canon Medical, Abbott, and Medtronic. Dr Koo has received institutional research grants from HeartFlow. Dr Maeng has received advisory board and lecture fees from AstraZeneca, Bayer, Boehringer Ingelheim, Bristol Myers Squibb, Boston Scientific, and Novo Nordics; and has received institutional research grants from Bayer, Philips Healthcare, and Novo Nordisk. Dr Jensen has received unrestricted institutional research grants from Siemens and HeartFlow. Dr Andreini has received research grants from GE Healthcare and Bracco. Dr Shinke has received research grants from Boston Scientific and Abbott Vascular. Dr Barbato has received speaker fees from Boston Scientific, Abbott Vascular, and GE. Dr De Bruyne has received consulting fees from Boston Scientific and Abbott Vascular; has received research grants from Coroventis Research, Pie Medical Imaging, CathWorks, Boston Scientific, Siemens, HeartFlow, and Abbott Vascular; and owns equity in Siemens, GE, Philips, HeartFlow, Edwards Lifesciences, Bayer, Sanofi, and Celyad. Dr Collet has received research grants from Biosensor, Coroventis Research, Medis Medical Imaging, Pie Medical Imaging, CathWorks, Boston Scientific, Siemens, HeartFlow, and Abbott Vascular; and has received consulting fees from HeartFlow, OpSens, Abbott Vascular, and Philips Volcano. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2024 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: A lesion-level risk prediction for acute coronary syndrome (ACS) needs better characterization., Objectives: This study sought to investigate the additive value of artificial intelligence-enabled quantitative coronary plaque and hemodynamic analysis (AI-QCPHA)., Methods: Among ACS patients who underwent coronary computed tomography angiography (CTA) from 1 month to 3 years before the ACS event, culprit and nonculprit lesions on coronary CTA were adjudicated based on invasive coronary angiography. The primary endpoint was the predictability of the risk models for ACS culprit lesions. The reference model included the Coronary Artery Disease Reporting and Data System, a standardized classification for stenosis severity, and high-risk plaque, defined as lesions with ≥2 adverse plaque characteristics. The new prediction model was the reference model plus AI-QCPHA features, selected by hierarchical clustering and information gain in the derivation cohort. The model performance was assessed in the validation cohort., Results: Among 351 patients (age: 65.9 ± 11.7 years) with 2,088 nonculprit and 363 culprit lesions, the median interval from coronary CTA to ACS event was 375 days (Q1-Q3: 95-645 days), and 223 patients (63.5%) presented with myocardial infarction. In the derivation cohort (n = 243), the best AI-QCPHA features were fractional flow reserve across the lesion, plaque burden, total plaque volume, low-attenuation plaque volume, and averaged percent total myocardial blood flow. The addition of AI-QCPHA features showed higher predictability than the reference model in the validation cohort (n = 108) (AUC: 0.84 vs 0.78; P < 0.001). The additive value of AI-QCPHA features was consistent across different timepoints from coronary CTA., Conclusions: AI-enabled plaque and hemodynamic quantification enhanced the predictability for ACS culprit lesions over the conventional coronary CTA analysis. (Exploring the Mechanism of Plaque Rupture in Acute Coronary Syndrome Using Coronary Computed Tomography Angiography and Computational Fluid Dynamics II [EMERALD-II]; NCT03591328)., Competing Interests: Funding Support and Author Disclosures This study received funding from HeartFlow Inc. The company performed the computational fluid dynamics, and artificial intelligence quantitative coronary plaque analysis but was not involved in the study design, collection, analysis, and interpretation of data; the writing of this paper; or the decision to submit it for publication. Dr Koo has received institutional research grants from Abbott, Philips, and HeartFlow Inc. Dr Nam has received institutional research grants from Abbott and Genoss. Dr Merkely has received direct personal payments for speaker fees or studies from Abbott, AstraZeneca, Biotronik, Boehringer Ingelheim, CSL Behring, Daiichi Sankyo, DUKE Clinical Institute, Medtronic, and Novartis and institutional grants from Abbott, AstraZeneca, Biotronik, Boehringer Ingelheim, Boston Scientific, Bristol Myers Squibb, CSL Behring, Daiichi Sankyo, DUKE Clinical Institute, Eli Lilly, Medtronic, Novartis, Terumo, and VIFOR Pharma. Dr de Bruyne has received institutional unrestricted research grants from Abbott, Boston Scientific, and Biotronik; has received consulting fees from Abbott, Opsens, and Boston Scientific; and is a shareholder for Siemens, GE, Bayer, Philips, HeartFlow Inc, Edwards Life Sciences, Sanofi, and Omega Pharma. Dr Ko has equity in Artrya and has received honoraria from Medtronic, Abbott Vascular, and Canon Medical. Dr Leipsic is a consultant for and holds stock options in HeartFlow Inc and modest personal core lab fees from Arineta. Dr Shah has received honoraria as a speaker for HeartFlow Inc. Dr Bax has received unrestricted research grants from Abbott and Edwards Lifesciences to the Department of Cardiology, Leiden University Medical Center, the Netherlands. Dr Shaw has received honoraria from HeartFlow Inc and Elucid Imaging. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2024 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Approximately half of the patients with angina and nonobstructive coronary artery disease (ANOCA) have evidence of coronary microvascular dysfunction (CMD)., Objectives: This study aims to characterize patients with ANOCA by measuring their minimal microvascular resistance and to examine the pattern of vascular remodeling associated with these measurements., Methods: The authors prospectively included patients with ANOCA undergoing continuous thermodilution assessment. Lumen volume and vessel-specific myocardial mass were quantified using coronary computed tomography angiography (CTA). CMD was defined as coronary flow reserve <2.5 and high minimal microvascular resistance as >470 WU., Results: A total of 153 patients were evaluated; 68 had CMD, and 22 of them showed high microvascular resistance. In patients with CMD, coronary flow reserve was 1.9 ± 0.38 vs 3.2 ± 0.81 in controls (P < 0.001). Lumen volume was significantly correlated with minimal microvascular resistance (r = -0.59 [95% CI: -0.45 to -0.71]; P < 0.001). In patients with CMD and high microvascular resistance, lumen volume was 40% smaller than in controls (512.8 ± 130.3 mm 3 vs 853.2 ± 341.2 mm 3 ; P < 0.001). Epicardial lumen volume assessed by coronary CTA was independently associated with minimal microvascular resistance (P < 0.001). The predictive capacity of lumen volume from coronary CTA for detecting high microvascular resistance showed an area under the curve of 0.79 (95% CI: 0.69-0.88)., Conclusions: Patients with CMD and high minimal microvascular resistance have smaller epicardial vessels than those without CMD. Coronary CTA detected high minimal microvascular resistance with very good diagnostic capacity. Coronary CTA could potentially aid in the diagnostic pathway for patients with ANOCA., Competing Interests: Funding Support and Author Disclosures Dr Collet has received research grants from Biosensor, Coroventis Research, Medis Medical Imaging, Pie Medical Imaging, CathWorks, Boston Scientific, Siemens, HeartFlow Inc, and Abbott Vascular; and consultancy fees from HeartFlow Inc, OpSens, Abbott Vascular, and Philips Volcano. Dr Mizukami has received consultancy fees from Zeon Medical Inc, research grants from Boston Scientific, and speaker fees from Abbott Vascular, Cath works, and Boston Scientific. Drs Buytaert and Munhoz have received research grants provided by the Cardiopath PhD program. Dr De Bruyne has received consultancy fees from Boston Scientific and Abbott Vascular; research grants from Coroventis Research, Pie Medical Imaging, CathWorks, Boston Scientific, Siemens, HeartFlow Inc, and Abbott Vascular; and owns equity in Siemens, GE, Philips, HeartFlow Inc, Edwards Life Sciences, Bayer, Sanofi, and Celyad. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2024 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Coronary disease complexity is commonly used to guide revascularization strategy in patients with multivessel disease (MVD)., Objectives: The aim of this study was to assess the interactive effects of coronary complexity on percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG) outcomes and identify the optimal threshold at which PCI can be considered a reasonable option., Methods: A total of 1,444 of 1,500 patients with MVD from the FAME (Fractional Flow Reserve versus Angiography for Multi-vessel Evaluation) 3 randomized trial were included in the analysis (710 CABG vs 734 PCI). SYNTAX (Synergy Between PCI With Taxus and Cardiac Surgery) scores were transformed into restricted cubic splines, and logistic regression models were fitted, with multiplicative interaction terms for revascularization strategy. Optimal thresholds at which PCI is a reasonable alternative to CABG were determined on the basis of Cox regression model performance., Results: The mean SYNTAX score (SS) was 25.9 ± 7.1. SS was associated with 1-year major adverse cardiac and cerebrovascular events among PCI patients and 3-year death, myocardial infarction, and stroke among CABG patients. Significant interactions were present between revascularization strategy and SS for 1- and 3-year composite endpoints (P for interaction <0.05 for all). In Cox regression models, outcomes were comparable between CABG and PCI for the 3-year primary endpoint for SS ≤24 (P = 0.332), with 44% of patients below this threshold and 32% below the conventional SS threshold of ≤22., Conclusions: In patients with MVD without left main disease, PCI and CABG outcomes remain comparable up to SS values in the mid- rather than low 20s, which allows the identification of a greater proportion of patients in whom PCI may be a reasonable alternative to CABG., Competing Interests: Funding Support and Author Disclosures This work was supported by grants from Medtronic and Abbott Vascular. Dr Dawson is supported by the Australian National Health and Medical Research Council and the Australian National Heart Foundation postgraduate scholarships. Dr Kobayashi serves as a consultant for Abbott Vascular. Dr Fearon has received institutional research support from Abbott Vascular, and Medtronic; and has stock options with HeartFlow. Dr De Bruyne has consulting relationships with Boston Scientific, Abbott Vascular, CathWorks, Siemens, and Coroventis Research; has received research grants from Abbott Vascular, Coroventis Research, CathWorks, and Boston Scientific; and holds minor equities in Philips-Volcano, Siemens, GE Healthcare, Edwards Lifesciences, HeartFlow, Sanofi, and Celyad. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2024 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Coronary CT angiography (CCTA) is well-established for diagnosis and stratification of coronary artery disease (CAD). Its usefulness in guiding percutaneous coronary interventions (PCI) and stent sizing is unknown., Methods: This is a sub-analysis of the Precise Percutaneous Coronary Intervention Plan (P3) study (NCT03782688). We analyzed 65 vessels with matched CCTA and pre-PCI optical coherence tomography (OCT) assessment. The CCTA-guided stent size was defined by the mean distal reference lumen diameter rounded up to the nearest stent diameter. The OCT lumen-guided stent size was the mean distal reference lumen diameter rounded to the closest stent diameter. The agreement on stent diameters was determined with Kappa statistics, Passing-Bablok regression analysis, and the Bland-Altman method., Results: The distal reference lumen diameter by CCTA and OCT were 2.75 ​± ​0.53 ​mm and 2.72 ​± ​0.55 ​mm (mean difference 0.06, limits of agreement -0.7 to 0.82). There were no proportional or systematic differences (coefficient A 1.06, 95% CI 0.84 to 1.3 and coefficient B -0.22, 95% CI -0.83 to 0.36) between methods. The agreement between the CCTA and OCT stent size was substantial (Cohen's weighted Kappa 0.74, 95% CI 0.64 to 0.85). Compared to OCT stent diameter, CCTA stent size was concordant in 52.3% of the cases; CCTA overestimated stent size in 20.0% and underestimated in 27.7%., Conclusion: CCTA accurately assessed the reference vessel diameter used for stent sizing. CCTA-based stent sizing showed a substantial agreement with OCT. CCTA allows for PCI planning and may aid in selecting stent diameter., Competing Interests: Declaration of competing interest TM reports receiving consulting fees from Zeon Medical and HeartFlow Inc, and speaker fees from Abbott Vascular. BLN has received an unrestricted institutional research grant from HeartFlow Inc. MM is supported by a grant from the Novo Nordisk Foundation (grant NNF22OC0074083). BKK received an Institutional Research Grant from Abbott Vascular, Boston Scientific Corporation, and Philips. BDB reports receiving consultancy fees from Boston Scientific and Abbott Vascular, research grants from Coroventis Research, Pie Medical Imaging, CathWorks, Boston Scientific, Siemens, HeartFlow Inc, and Abbott Vascular, and owning equity in Siemens, GE, Philips, HeartFlow Inc, Edwards Life Sciences, Bayer, Sanofi, Celyad. CC reports receiving research grants from Biosensor, Coroventis Research, Medis Medical Imaging, Pie Medical Imaging, CathWorks, Boston Scientific, Siemens, HeartFlow Inc, Abbott Vascular, and consultancy fees from HeartFlow Inc, OpSens, Abbott Vascular, and Philips Volcano. The other authors have no further disclosures., (Copyright © 2024 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.)

Background: Cardiac damage (CD) staging enhances risk stratification in patients with clinically significant aortic stenosis (AS). We aimed to assess the prognostic value and reclassification rate of right heart catheterization (RHC) compared with transthoracic echocardiography (TTE) in characterising CD staging at 3-year follow-up in patients with clinically significant AS, to identify patients that would benefit from RHC for prognostic stratification, and to test the prognostic value of combined CD staging., Methods: An observational cohort study of 432 AS patients undergoing TTE and RHC were divided into moderate or asymptomatic severe (m/asAS) and symptomatic severe (ssAS) AS. Kaplan-Meier curves were used to compare survival. The accuracy in prognostic stratification was tested by area under the receiver operating characteristic curve analysis and Delong test., Results: In both cohorts, TTE- and RHC-derived staging systems had prognostic value, although the agreement between them appeared moderate. A higher proportion of patients were assigned to stage 2 by TTE than by RHC. Patients in TTE-derived stage 2 had a high reclassification rate, with 40%-50% presenting with right chamber involvement (stages 3-4) according to RHC. Discordant cases were significantly older, with higher prevalence of atrial fibrillation, markedly elevated N-terminal pro-B-type natriuretic peptide, and higher indexed left atrial volume, E/e', and systolic pulmonary artery pressure vs concordant cases (P < 0.05). The combined CD staging, integrating TTE and RHC, was more accurate in predicting mortality than the TTE-derived system (P < 0.05)., Conclusions: In patients with m/asAS and ssAS, the combined CD staging, derived from TTE and RHC, was more accurate in predicting mortality than TTE alone. In a subset of AS patients, the integration of RHC may significantly improve prognostic stratification., (Copyright © 2023 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Background and Aims: Coronary hemodynamics impact coronary plaque progression and destabilization. The aim of the present study was to establish the association between focal vs. diffuse intracoronary pressure gradients and wall shear stress (WSS) patterns with atherosclerotic plaque composition., Methods: Prospective, international, single-arm study of patients with chronic coronary syndromes and hemodynamic significant lesions (fractional flow reserve [FFR] ≤ 0.80). Motorized FFR pullback pressure gradient (PPG), optical coherence tomography (OCT), and time-average WSS (TAWSS) and topological shear variation index (TSVI) derived from three-dimensional angiography were obtained., Results: One hundred five vessels (median FFR 0.70 [Interquartile range (IQR) 0.56-0.77]) had combined PPG and WSS analyses. TSVI was correlated with PPG (r = 0.47, [95% Confidence Interval (95% CI) 0.30-0.65], p < 0.001). Vessels with a focal CAD (PPG above the median value of 0.67) had significantly higher TAWSS (14.8 [IQR 8.6-24.3] vs. 7.03 [4.8-11.7] Pa, p < 0.001) and TSVI (163.9 [117.6-249.2] vs. 76.8 [23.1-140.9] m -1 , p < 0.001). In the 51 vessels with baseline OCT, TSVI was associated with plaque rupture (OR 1.01 [1.00-1.02], p = 0.024), PPG with the extension of lipids (OR 7.78 [6.19-9.77], p = 0.003), with the presence of thin-cap fibroatheroma (OR 2.85 [1.11-7.83], p = 0.024) and plaque rupture (OR 4.94 [1.82 to 13.47], p = 0.002)., Conclusions: Focal and diffuse coronary artery disease, defined using coronary physiology, are associated with differential WSS profiles. Pullback pressure gradients and WSS profiles are associated with atherosclerotic plaque phenotypes. Focal disease (as identified by high PPG) and high TSVI are associated with high-risk plaque features., Clinical Trial Registration: https://clinicaltrials,gov/ct2/show/NCT03782688., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Background: To identify anatomical and morphological plaque features predictors of PCI and create a multiparametric score to increase the predictive yield. Moreover, we assessed the incremental predictive value of FFR CT (Fractional Flow Reserve derived from CCTA) trans-lesion gradient (ΔFFR CT ) when integrated into the score., Methods: Observational cohort study including patients undergoing CCTA for suspected coronary artery disease, with FFR CT available, referred to invasive coronary angiogram and assessment of fractional flow reserve. Plaque analysis was performed using validated semi-automated software. Logistic regression was performed to identify anatomical and morphological plaque features predictive of PCI. Optimal thresholds were defined by area under the receiver-operating characteristics curve (AUC) analysis. A scoring system was developed in a derivation cohort (70 ​% of the study population) and tested in a validation cohort (30 ​% of patients)., Results: The overall study population included 340 patients (455 vessels), among which 238 patients (320 vessels) were included in the derivation cohort. At multivariate logistic regression analysis, absence of left main disease, diameter stenosis (DS), non-calcified plaque (NCP) volume, and percent atheroma volume (PAV) were independent predictors of PCI. Optimal thresholds were: DS ​≥ ​50 ​%, volume of NCP>113 ​mm 3 and PAV>17 ​%. A weighted score (CT-PCI Score) ranging from 0 to 11 was obtained. The AUC of the score was 0.80 (95%CI 0.74-0.86). The integration of ΔFFR CT in the CT-PCI score led to a mild albeit not significant increase in the AUC (0.82, 95%CI 0.77-0.87, p ​= ​0.328)., Conclusions: Plaque anatomy and morphology derived from CCTA could aid in identifying patients amenable to PCI., Competing Interests: Declaration of competing interest MB, PP, DTB, AL and MMV report research grants provided by Cardiopath Ph.D. program. NM has received speaker fees from Abbott. CC reports receiving research grants from Biosensor, Coroventis Research, Medis Medical Imaging, Pie Medical Imaging, Cathworks, Boston Scientific, Siemens, HeartFlow Inc., and Abbott Vascular; and consultancy fees from Heart Flow Inc, Opsens, Abbott Vascular, and Philips Volcano. BDB reports receiving consultancy fees from Boston Scientific, and Abbott and receiving research grants from Coroventis Research, Pie Medical Imaging, Cathworks, Boston Scientific, Siemens, HeartFlow Inc., and Abbott Vascular. DA reports research grants from GE Healthcare and Bracco. The other authors have nothing to disclose., (Copyright © 2024 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.)

Background: Coronary flow reserve (CFR) and microvascular resistance reserve (MRR) can, in principle, be derived by any method assessing coronary flow., Objectives: The aim of this study was to compare CFR and MRR as derived by continuous (CFR cont and MRR cont ) and bolus thermodilution (CFR bolus and MRR bolus )., Methods: A total of 175 patients with chest pain and nonobstructive coronary artery disease were studied. Bolus and continuous thermodilution measurements were performed in the left anterior descending coronary artery. MRR was calculated as the ratio of CFR to fractional flow reserve and corrected for changes in systemic pressure. In 102 patients, bolus and continuous thermodilution measurements were performed in duplicate to assess test-retest reliability., Results: Mean CFR bolus was higher than CFR cont (3.47 ± 1.42 and 2.67 ± 0.81 [P < 0.001], mean difference 0.80, upper limit of agreement 3.92, lower limit of agreement -2.32). Mean MRR bolus was also higher than MRR cont (4.40 ± 1.99 and 3.22 ± 1.02 [P < 0.001], mean difference 1.2, upper limit of agreement 5.08, lower limit of agreement -2.71). The correlation between CFR and MRR values obtained using both methods was significant but weak (CFR, r = 0.28 [95% CI: 0.14-0.41]; MRR, r = 0.26 [95% CI: 0.16-0.39]; P < 0.001 for both). The precision of both CFR and MRR was higher when assessed using continuous thermodilution compared with bolus thermodilution (repeatability coefficients of 0.89 and 2.79 for CFR cont and CFR bolus , respectively, and 1.01 and 3.05 for MRR cont and MRR bolus , respectively)., Conclusions: Compared with bolus thermodilution, continuous thermodilution yields lower values of CFR and MRR accompanied by an almost 3-fold reduction of the variability in the measured results., Competing Interests: Funding Support and Author Disclosures Drs Paolisso and Esposito are supported by a research grant from the CardioPaTh PhD Program. Dr Barbato has received speaker fees from Abbott Vascular, Boston Scientific, and GE Healthcare. Dr Collet has received research grants from Biosensors, GE Healthcare, Medis Medical Imaging, Pie Medical Imaging, CathWorks, Boston Scientific, Siemens, HeartFlow, and Abbott Vascular; and has received consultancy fees from HeartFlow, Opsens, Pie Medical Imaging, Abbott Vascular, and Philips. Dr De Bruyne has institutional consulting relationships with Boston Scientific, Abbott Vascular, CathWorks, Siemens, GE Healthcare, and Coroventis Research; has received institutional research grants from Abbott Vascular, Coroventis Research, CathWorks, and Boston Scientific; and has minor equity holdings in Philips, Siemens, GE Healthcare, Edwards Lifesciences, HeartFlow, Opsens, Celiad, Bayer, and Sanofi. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2023 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: The interplay between coronary hemodynamics and plaque characteristics remains poorly understood., Objectives: The aim of this study was to compare atherosclerotic plaque phenotypes between focal and diffuse coronary artery disease (CAD) defined by coronary hemodynamics., Methods: This multicenter, prospective, single-arm study was conducted in 5 countries. Patients with functionally significant lesions based on an invasive fractional flow reserve ≤0.80 were included. Plaque analysis was performed by using coronary computed tomography angiography and optical coherence tomography. CAD patterns were assessed using motorized fractional flow reserve pullbacks and quantified by pullback pressure gradient (PPG). Focal and diffuse CAD was defined according to the median PPG value., Results: A total of 117 patients (120 vessels) were included. The median PPG was 0.66 (IQR: 0.54-0.75). According to coronary computed tomography angiography analysis, plaque burden was higher in patients with focal CAD (87% ± 8% focal vs 82% ± 10% diffuse; P = 0.003). Calcifications were significantly more prevalent in patients with diffuse CAD (Agatston score per vessel: 51 [IQR: 11-204] focal vs 158 [IQR: 52-341] diffuse; P = 0.024). According to optical coherence tomography analysis, patients with focal CAD had a significantly higher prevalence of circumferential lipid-rich plaque (37% focal vs 4% diffuse; P = 0.001) and thin-cap fibroatheroma (TCFA) (47% focal vs 10% diffuse; P = 0.002). Focal disease defined by PPG predicted the presence of TCFA with an area under the curve of 0.73 (95% CI: 0.58-0.87)., Conclusions: Atherosclerotic plaque phenotypes associate with intracoronary hemodynamics. Focal CAD had a higher plaque burden and was predominantly lipid-rich with a high prevalence of TCFA, whereas calcifications were more prevalent in diffuse CAD. (Precise Percutaneous Coronary Intervention Plan [P3]; NCT03782688)., Competing Interests: Funding and Author Disclosures The study was sponsored by the Cardiac Research Institute Aalst with unrestricted grants from HeartFlow Inc. Dr Mizukami has received consulting fees from Zeon Medical and HeartFlow Inc; and speaker fees from Abbott Vascular. Dr Leipsic is a consultant and has holding stock options in Circle CVI and HeartFlow Inc; has received a research grant from GE; and modest speaker fees from GE and Philips. Drs Sonck and Munhoz have received research grants provided by the Cardiopath Ph.D. program. Dr Nørgaard has received unrestricted institutional research grants from Siemens and HeartFlow Inc. Dr Otake has received research grants from Abbott Vascular; and speaker fees from HeartFlow Inc and Abbott Vascular. Dr Ko has received consulting fees from Canon Medical, Abbott, and Medtronic. Dr Koo has received institutional research grants from HeartFlow Inc. Dr Maeng has received advisory board and lecture fees from AstraZeneca, Bayer, Boehringer Ingelheim, Bristol Myers Squibb, Boston Scientific, and Novo Nordisk; and research grants from Bayer and Philips Healthcare. Dr Jensen has received unrestricted institutional research grants from Siemens and HeartFlow Inc. Dr Andreini has received research grants from GE Healthcare and Bracco. Dr Shinke has received research grants from Boston Scientific and Abbott Vascular. CT is an employee of HeartFlow Inc. Dr Barbato has received speaker fees from Boston Scientific, Abbott Vascular, and GE. Dr Johnson has received internal funding from the Weatherhead PET Center for Preventing and Reversing Atherosclerosis; significant institutional research support from St. Jude Medical (CONTRAST [Can Contrast Injection Better Approximate FFR Compared to Pure Resting Physiology?]; NCT02184117) and Philips/Volcano Corporation (DEFINE-FLOW [Combined Pressure and Flow Measurements to Guide Treatment of Coronary Stenoses]; NCT02328820) for studies using intracoronary pressure and flow sensors; has an institutional licensing agreement with Boston Scientific for the smart-minimum FFR algorithm commercialized under 510(k) K191008; and has pending patents on diagnostic methods for quantifying aortic stenosis and transcatheter aortic valve replacement physiology, as well as algorithms to correct pressure tracings from fluid-filled catheters. Dr De Bruyne has received consultancy fees from Boston Scientific and Abbott Vascular; research grants from Coroventis Research, Pie Medical Imaging, CathWorks, Boston Scientific, Siemens, HeartFlow Inc, and Abbott Vascular; and owns equity in Siemens, GE, Philips, HeartFlow Inc, Edwards Life Sciences, Bayer, Sanofi, and Celyad. Dr Collet has received research grants from Biosensor, Coroventis Research, Medis Medical Imaging, Pie Medical Imaging, CathWorks, Boston Scientific, Siemens, HeartFlow Inc, and Abbott Vascular; and consultancy fees from HeartFlow Inc, OpSens, Abbott Vascular, and Philips Volcano. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Low fractional flow reserve (FFR) after percutaneous coronary intervention (PCI) has been associated with adverse clinical outcomes. Hitherto, this assessment has been independent of the epicardial vessel interrogated., Objectives: This study sought to assess the predictive capacity of post-PCI FFR for target vessel failure (TVF) stratified by coronary artery., Methods: We performed a systematic review and individual patient-level data meta-analysis of randomized clinical trials and observational studies with protocol-recommended post-PCI FFR assessment. The difference in post-PCI FFR between left anterior descending (LAD) and non-LAD arteries was assessed using a random-effect models meta-analysis of mean differences. TVF was defined as a composite of cardiac death, target vessel myocardial infarction, and clinically driven target vessel revascularization., Results: Overall, 3,336 vessels (n = 2,760 patients) with post-PCI FFR measurements were included in 9 studies. The weighted mean post-PCI FFR was 0.89 (95% CI: 0.87-0.90) and differed significantly between coronary vessels (LAD = 0.86; 95% CI: 0.85 to 0.88 vs non-LAD = 0.93; 95% CI: 0.91-0.94; P < 0.001). Post-PCI FFR was an independent predictor of TVF, with its risk increasing by 52% for every reduction of 0.10 FFR units, and this was mainly driven by TVR. The predictive capacity for TVF was poor for LAD arteries (AUC: 0.52; 95% CI: 0.47-0.58) and moderate for non-LAD arteries (AUC: 0.66; 95% CI: 0.59-0.73; LAD vs non-LAD arteries, P = 0.005)., Conclusions: The LAD is associated with a lower post-PCI FFR than non-LAD arteries, emphasizing the importance of interpreting post-PCI FFR on a vessel-specific basis. Although a higher post-PCI FFR was associated with improved prognosis, its predictive capacity for events differs between the LAD and non-LAD arteries, being poor in the LAD and moderate in the non-LAD vessels., Competing Interests: Funding Support and Author Disclosures Dr Collet received research grants from Biosensors, HeartFlow Inc, Abbott Vascular, Insight Lifetech, GE Healthcare, Siemens and Shockwave Medical. Dr Johnson has received internal funding from the Weatherhead PET Center for Preventing and Reversing Atherosclerosis; has received significant institutional research support from St. Jude Medical (CONTRAST, NCT02184117) and Philips Volcano (DEFINE-FLOW, NCT02328820) for studies using intracoronary pressure and flow sensors; has an institutional licensing agreement with Boston Scientific for the smart-minimum FFR algorithm commercialized under 510(k) K191008; and has pending patents on diagnostic methods for quantifying aortic stenosis and TAVI physiology and also algorithms to correct pressure tracings from fluid-filled catheters. Dr Mizukami has received consultancy fees from Zeon Medical. Dr Fearon receives institutional research support from Abbott Vascular, Boston Scientific, Medtronic, and Edwards Lifesciences; he has a consulting relationship with CathWorks and Siemens; and he owns minor stock options in HeartFlow. Dr Berry receives research funding from the British Heart Foundation grant (RE/18/6134217); and is employed by the University of Glasgow, which holds consultancy and research agreements for his work with Abbott Vascular, AstraZeneca, Boehringer Ingelheim, Causeway Therapeutics, Coroventis, Genentech, GlaxoSmithKline, HeartFlow, Menarini, Neovasc, Siemens Healthcare, and Valo Health. Dr Sonck is supported by a grant provided by the CardioPath PhD program. Dr Collison has received honoraria/speaker fees from Abbott. Dr Koo has received an institutional research grant from St. Jude Medical (Abbott Vascular) and Philips Volcano. Dr Meneveau has received consultancy and speaker fees from Abbott Vascular, Edwards Lifesciences, Terumo, Boston Scientific, Bayer Healthcare, BMS-Pfizer, Boehringer, and AstraZeneca. Dr Oldroyd is an employee of Biosensors International. Dr Leipsic is a consultant for and holds stock options in Circle CVI and HeartFlow; and has a research grant from GE Healthcare. Dr Taylor is an employee of HeartFlow Inc. Dr Ko has received consultancy fees from Abbott Vascular and Medtronic; and has received research support from Canon Medical. Dr Perera has received research grant support from Abbott Vascular, HeartFlow, and Philips. Dr Leone received consultant fees and honoraria for lectures in sponsored symposia with Abbott Vascular and Bracco Imaging/ACIST Medical. Dr Matsuo has received consultancy fees from Zeon Medical; and has received speaker fees from Abbott Vascular Japan, Philips, and Boston Scientific. Dr Amabile reports consulting/proctoring fees from Abbott Vascular, Boston Scientific, and Shockwave Medical; and has received an institutional research grant from Abbott Vascular and Boston Scientific. Dr Piróth has received consultancy and speaker fees from Abbott Vascular, Opsens, and Boston Scientific. Dr Toth has received consultancy fees and research support from Abbott, Biotronik, Medtronic, and Terumo. Dr Ihdayhid reports receiving consulting honorarium from Abbott Medical, Edwards Lifesciences, Boston Scientific, Artrya Pty Ltd (including equity interest). Dr West is an employee of Abbott Vascular. Dr Munhoz is supported with a PhD grant from CardioPath. Dr Barbato has received speaker fees from Abbott and Boston Scientific. Dr Engstrøm has received consultancy and speaker fees from Abbott Vascular, Novo Nordisk, and Bayer AS. Dr Escaned is supported by the Intensification of Research Activity project INT22/00088 from Spanish Instituto de Salud Carlos III, and served as speaker and advisory board member for Abbott and Philips. Dr Ali has received institutional grant support Abbott, Abiomed, ACIST Medical, Amgen, Boston Scientific, Cathworks, Canon, Conavi, Heartflow, Inari, Medtronic Inc, National Institute of Health, Nipro, Opsens Medical, Medis, Philips, Shockwave, Siemens, Spectrawave, Teleflex; and consulting fees from Abiomed, AstraZeneca, Boston Scientific, Cathworks, Opsens, Philips, Shockwave and equity in Elucid, Lifelink, Spectrawave, Shockwave, VitalConnect. Dr Kern has received speaker fees from Abbott, ACIST Medical, Boston Scientific, Opsens, and Philips. Dr Pijls has received research grants from Abbott and Hexacath and consultancy fees from Abbott, GE, Philips, and HeartFlow and have equity in GE, Philips, and Heartflow. Dr De Bruyne has received institutional consulting fees from Abbott Vascular, Boston Scientific, Siemens, and GE; has received institutional grant support from Abbott Vascular, Boston Scientific, Biotronic, CathWorks, Pie Medical, and HeartFlow; and holds minor equities in Philips, Siemens, GE, Bayer, HeartFlow, Edwards Lifesciences, and Ceyliad. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2023 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background and Aims: Post-percutaneous coronary intervention (PCI) fractional flow reserve (FFR) reflects residual atherosclerotic burden and is associated with future events. How much post-PCI FFR can be predicted based on baseline basic information and the clinical relevance have not been investigated., Methods: We compiled a multicenter registry of patients undergoing pre- and post-PCI FFR. Machine-learning (ML) algorithms were designed to predict post-PCI FFR levels from baseline demographics, quantitative coronary angiography, and pre-PCI FFR. FFR deviation was defined as actual minus ML-predicted post-PCI FFR levels, and its association with incident target vessel failure (TVF) was evaluated., Results: Median (IQR) pre- and post-PCI FFR values were 0.71 (0.61, 0.77) and 0.88 (0.84, 0.93), respectively. The Spearman correlation coefficient of the actual and predicted post-PCI FFR was 0.54 (95% CI: 0.52, 0.57). FFR deviation was non-linearly associated with incident TVF (HR [95% CI] with Q3 as reference: 1.65 [1.14, 2.39] in Q1, 1.42 [0.98, 2.08] in Q2, 0.81 [0.53, 1.26] in Q4, and 1.04 [0.69, 1.56] in Q5). A model with polynomial function of continuous FFR deviation indicated increasing TVF risk for FFR deviation ≤0 but plateau risk with FFR deviation >0., Conclusions: An ML-based algorithm using baseline data moderately predicted post-PCI FFR. The deviation of post-PCI FFR from the predicted value was associated with higher vessel-oriented event., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Dr. Koo reported receiving grants from Abbott Vascular and Philips Volcano during the conduct of the study. Dr. Tanaka reported receiving personal fees from Abbott Vascular Japan and personal fees from Daiichi-Sankyo Co Ltd during the conduct of the study. Dr. Azzalini received honoraria from Teleflex, Abiomed, Asahi Intecc, Philips, GE Healthcare, Abbott Vascular, and Cardiovascular System, Inc. No other disclosures were reported. Data described in the manuscript, code book, and analytic code will be made available upon request pending application and approval., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Background: The functional SYNTAX score (FSS), which incorporates functional information as assessed by fractional flow reserve (FFR), is a better predictor of outcome after percutaneous coronary intervention (PCI) in patients with less complex coronary artery disease (CAD)., Objectives: This study sought to test the prognostic value of the FSS in patients with complex CAD eligible for coronary artery bypass grafting (CABG)., Methods: The FAME 3 (Fractional Flow Reserve Versus Angiography for Multivessel Evaluation 3) trial compared FFR-guided PCI with CABG in patients with angiographic 3-vessel CAD. In this prespecified substudy, the angiographic core laboratory calculated the SYNTAX score (SS) and then the FSS by eliminating lesions that were not significant based on FFR. Outcomes in the PCI patients based on the FSS and the SS were compared to each other and to the patients treated with CABG., Results: The FSS reclassified more than one-quarter of patients from an SS >22 to an FSS ≤22. In the 50% of PCI patients who had an FSS ≤22, the primary endpoint occurred at a similar rate to patients treated with CABG (P = 0.77). The primary endpoint in patients without functionally significant 3-vessel CAD was similar to the CABG group (P = 0.97). The rate of myocardial infarction and revascularization among all deferred lesions was 0.5% and 3.2%, respectively., Conclusions: By measuring the FSS, one can identify 50% of patients who have a similar outcome at 1 year with PCI compared with CABG. Lesions deferred from PCI based on FFR have a low event rate., Competing Interests: Funding Support and Author Disclosures Dr Kobayashi serves as a consultant for Abbott Vascular. Dr Oldroyd serves as a chief medical officer for Biosensors International. Dr Reardon serves as a consultant for Medtronic, Boston Scientific, Abbott, and Gore Medical. De Bruyne has stock or stock options with Edwards LifeSciences, General Electric, HeartFlow, Philips, and Siemens. Dr Pijls has received research funding from Abbott; has consulting relationships with Abbott and Opsens; and has stock or stock options with ASML, General Electric, HeartFlow, Hexacath, and Philips. Dr Fearon has received institutional research support from Abbott Vascular, Boston Scientific, and Medtronic; has a consulting relationship with CathWorks and Siemens; and has stock options with HeartFlow. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2023 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Competing Interests: Funding Support and Author Disclosures The authors have reported that they have no relationships relevant to the contents of this paper to disclose.

Background/purpose: Matching phasic pressure tracings between a fluid-filled catheter and high-fidelity pressure wire has received limited attention, although each part contributes half of the information to clinical decisions. We aimed to study the impact of a novel and automated method for improving the phasic calibration of a fluid-filled catheter by accounting for its oscillatory behavior., Methods/materials: Retrospective analysis of drift check tracings was performed using our algorithm that corrects for mean difference (offset), temporal delays (timing), differential sensitivity of the manifold transducer and pressure wire sensor (gain), and the oscillatory behavior of the fluid-filled catheter described by its resonant frequency and damping factor (how quickly oscillations disappear after a change in pressure)., Results: Among 2886 cases, correcting for oscillations showed a large improvement in 28 % and a medium improvement in 41 % (decrease in root mean square error >0.5 mmHg to <1 or 1-2 mmHg, respectively). 96 % of oscillators were underdamped with median damping factor 0.27 and frequency 10.6 Hz. Fractional flow reserve or baseline Pd/Pa demonstrated no clinically important bias when ignoring oscillations. However, uncorrected subcycle non-hyperemic pressure ratios (NHPR) displayed both bias and scatter., Conclusions: By automatically accounting for the oscillatory behavior of a fluid-filled catheter system, phasic matching against a high-fidelity pressure wire can be improved compared to standard equalization methods. The majority of tracings contain artifacts, mainly due to underdamped oscillations, and neglecting them leads to biased estimates of equalization parameters. No clinically important bias exists for whole-cycle metrics, in contrast to significant effects on subcycle NHPR., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: An increase in fractional flow reserve (FFR) after percutaneous coronary intervention (PCI) is associated with improvement in angina. Coronary artery disease (CAD) patterns (focal vs diffuse) influence the FFR change after stenting and may predict angina relief., Objectives: The aim of this study was to investigate the differential improvement in patient-reported outcomes after PCI in focal and diffuse CAD as defined by the pullback pressure gradient (PPG)., Methods: This is a subanalysis of the TARGET-FFR (Trial of Angiography vs. pressure-Ratio-Guided Enhancement Techniques-Fractional Flow Reserve) randomized clinical trial. The 7-item Seattle Angina Questionnaire (SAQ-7) was administered at baseline and 3 months after PCI. The PPG index was calculated from manual pre-PCI FFR pullbacks. The median PPG value was used to define focal and diffuse CAD. Residual angina was defined as an SAQ-7 score <100., Results: A total of 103 patients were analyzed. There were no differences in the baseline characteristics between patients with focal and diffuse CAD. Focal disease had larger increases in FFR after PCI than patients with diffuse disease (0.30 ± 0.14 vs 0.19 ± 0.12; P < 0.001). Patients with focal disease who underwent PCI for focal CAD had significantly higher SAQ-7 summary scores at follow-up than those with diffuse CAD (87.1 ± 20.3 vs 75.6 ± 24.4; mean difference = 11.5 [95% CI: 2.8-20.3]; P = 0.01). After PCI, residual angina was present in 39.8% but was significantly less in those with treated focal CAD (27.5% vs 51.9%; P = 0.020)., Conclusions: Residual angina after PCI was almost twice as common in patients with a low PPG (diffuse disease), whereas patients with a high PPG (focal disease) reported greater improvement in angina and quality of life. The baseline pattern of CAD can predict the likelihood of angina relief. (Trial of Angiography vs. pressure-Ratio-Guided Enhancement Techniques-Fractional Flow Reserve [TARGET-FFR]; NCT03259815)., Competing Interests: Funding Support and Author Disclosures Dr Collet has received research grants from Biosensor, Coroventis Research, Medis Medical Imaging, Pie Medical Imaging, CathWorks, Boston Scientific, Siemens, HeartFlow, and Abbott Vascular; and has received consultancy fees from HeartFlow, OpSens, Abbott Vascular, and Philips Volcano. Dr Collison has received consultancy and speaker fees from Abbott. Dr Munhoz has received research grants provided by the Cardiopath PhD program. Dr Berry is employed by the University of Glasgow, which holds consultancy and research agreements for his work with Abbott Vascular, AstraZeneca, Auxilius Pharma, Boehringer Ingelheim, Causeway Therapeutics, Coroventis, Genentech, GlaxoSmithKline, HeartFlow, Menarini, Neovasc, Siemens Healthcare, and Valo Health; and has received research funding from the British Heart Foundation grant (RE/18/6134217) and EPSRC (EP/R511705/1, EP/S030875/1). Dr De Bruyne has received consultancy fees from Boston Scientific and Abbott Vascular; has received research grants from Coroventis Research, Pie Medical Imaging, CathWorks, Boston Scientific, Siemens, HeartFlow, and Abbott Vascular; and owns equity in Siemens, GE, Philips, HeartFlow, Edwards Life Sciences, Bayer, Sanofi, and Celyad. Dr Oldroyd is an employee of Biosensors International. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Endomyocardial biopsy (EMB) facilitates a histopathologic diagnosis with unique prognostic and therapeutic implications in both native and donor hearts. It is a relatively safe procedure, with an overall complication rate ranging from <1% to 6% depending on the experience of the operator, the clinical status of the patient, the presence or absence of left bundle branch block, the access site, and the site of procurement (right ventricular [RV] vs left ventricular [LV] approach)., Objectives: This study aimed to assess the incidence of procedure-related complications in a real-world population. EMBs were performed either for surveillance of rejection episodes after heart transplantation or for diagnosis of etiology of cardiomyopathy., Methods: The authors retrospectively analyzed 1,368 biopsies obtained in 561 consecutive patients between May 2011 and May 2021. Patients were stratified according to the underlying heart disease, sex, age, access site, body mass index, and RV vs LV approach., Results: The analysis revealed an overall complication rate of 4.1%. Serious life-threatening cardiac complications occurred in <1% of EMBs, with tamponade necessitating pericardiocentesis in 0.2% and urgent cardiac surgery in 0.1% of the procedures. Minor complications occurred in 3.3% of the overall population and were more often encountered during LV EMBs (3.9%) and when the native heart was sampled (5.3%)., Conclusions: In experienced hands, LV and RV EMB for heart transplantation rejection surveillance and cardiomyopathy diagnosis is a safe procedure with low risk of complications. Older, female patients and those undergoing native heart EMB were more prone to complications following EMB., Competing Interests: Funding Support and Author Disclosures Drs Paolisso, Esposito, Bertolone, and Fabbricatore are supported by a research grant from the CardioPaTh PhD Program. Dr De Bruyne owns minor equity in Philips Volcano, Siemens, GE Healthcare, Edwards Lifesciences, HeartFlow, Opsens, and Celiad. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2022 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: To investigate the learning curve and the minimum number of cases required for a cardiologist in training to acquire the skills to an accurate pre-TAVI cardiac CT (CCT) analysis using a semi-automatic software., Methods: In this prospective, observational study, 40 CCTs of patients scheduled for TAVI were independently evaluated twice by 5 readers (80 readings each, 400 in total): a certified TAVI-CT specialist served as the reference reader (RR) and 4 cardiology fellows (2 interventional and 2 non-invasive cardiac imaging) as readers. The primary outcome was the minimum number of cases required to achieve an accuracy in imaging interpretation ≥80%, defined as the agreement between each reader and the RR in both balloon and self-expandable valve size choice. The secondary outcomes were the intra- and inter-observer variability., Results: After 50 readings (25 cases repeated twice) cardiology fellows were able to select the appropriate valve size with ≥ 80% of accuracy compared to the RR, independently of valve calcification, image quality and slice thickness. Learning curves of both interventional and non-invasive cardiac imaging fellows showed a similar trend. Cardiology fellows achieved a very high intra- and inter-observer reliability for both perimeter and area assessment, with an intraclass correlation coefficient (ICC) ranging from 0.96 to 0.99., Conclusions: Despite the individual differences, cardiology fellows required 50 readings (25 cases repeated twice) to get adequately skilled in the pre-TAVI CCT interpretation. These results provide valuable information for developing adequate training sessions and education protocols for both companies and cardiologists involved., Competing Interests: Declaration of competing interest The authors declare that they have no competing interests., (Copyright © 2022 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.)

Background: Diabetes mellitus is a major risk factor for coronary artery disease (CAD) and may provoke structural and functional changes in coronary vasculature. The coronary volume to left ventricular mass (V/M) ratio is a new anatomical parameter capable of revealing a potential physiological imbalance between coronary vasculature and myocardial mass. The aim of this study was to examine the V/M derived from coronary computed tomography angiography (CCTA) in patients with diabetes., Methods: Patients with clinically suspected CAD enrolled in the ADVANCE (Assessing Diagnostic Value of Non-invasive FFRCT in Coronary Care) registry and known diabetic status were included. Coronary artery volume and left ventricular myocardial mass were analyzed from CCTA and the V/M ratio was calculated and compared between patients with and without diabetes., Results: Of the 3053 patients (age 66 ​± ​10 years; 66% male) with known diabetic status, diabetes was present in 21.9%. Coronary volume was lower in patients with diabetes compared to those without diabetes (2850 ​± ​940 ​mm 3 vs. 3040 ​± ​970 ​mm 3 , p ​< ​0.0001), whereas the myocardial mass was comparable between the 2 groups (122 ​± ​33 ​g vs. 122 ​± ​32 ​g, p ​= ​0.70). The V/M ratio was significantly lower in patients with diabetes (23.9 ​± ​6.8 ​mm 3 /g vs. 25.7 ​± ​7.5 ​mm 3 /g, p ​< ​0.0001). Among subjects with obstructive CAD (n ​= ​2191, 24.0% diabetics) and non-obstructive CAD (16.7% diabetics), the V/M ratio was significantly lower in patients with diabetes compared to those without (23.4 ​± ​6.7 ​mm 3 /g vs. 25.0 ​± ​7.3 ​mm 3 /g, p ​< ​0.0001 and 25.6 ​± ​6.9 ​mm 3 /g vs. 27.3 ​± ​7.6 ​mm 3 /g, respectively, p ​= ​0.006)., Conclusion: The V/M ratio was significantly lower in patients with diabetes compared to non-diabetics, even after correcting for obstructive coronary stenosis. The clinical value of the reduced V/M ratio in diabetic patients needs further investigation., Competing Interests: Declaration of competing interest The department of Cardiology, Leiden University Medical Center, Leiden, the Netherlands has received unrestricted research grants from Medtronic, Biotronik, Boston Scientific, and Edwards Lifesciences. Dr. Patel has received research grants from HeartFlow, Bayer, Janssen, and the National Heart, Lung, and Blood Institute; and has served on the advisory board for HeartFlow, Bayer, and Janssen. Dr. Nørgaard has received unrestricted institutional research grants from Siemens and HeartFlow. Dr. Fairbairn has served on the Speakers Bureau for HeartFlow. Dr. Nieman has received institutional research support from Siemens Healthineers, HeartFlow, GE Healthcare, and Bayer Healthcare. Dr. Berman has received unrestricted research support from HeartFlow. Dr. Hurwitz Koweek has received research support and speaking fees from HeartFlow and Siemens. Dr. Pontone has received institutional research grant and/or honorarium as consultant/speaker from GE Healthcare, Boehringer, Bracco, Medtronic, Bayer, and HeartFlow. Dr. Sonck has received research grant support from the Cardiopath PhD program. Dr. Rabbat has served as a consultant for HeartFlow. Dr. De Bruyne has received consulting fees from Abbott, Opsens, and Boston Scientific; and is a shareholder for Siemens, GE Healthcare, Bayer, Philips, HeartFlow, Edwards Lifesciences, and Sanofi. Dr. Rogers is employee of and owns equity in HeartFlow. Dr. Leipsic has received research grants from GE Healthcare and Edwards Lifesciences; and has served as a consultant for and holds stock options in Circle Cardiovascular Imaging and HeartFlow Inc. Dr. Bax has received speaker fees from Abbot Vascular. Dr. Knuuti has received consultancy fees from GE Healthcare and AstraZeneca and speaker fees from GE Healthcare, Bayer, Lundbeck, Boehringer-Ingelheim and Merck, outside of the submitted work. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Low fractional flow reserve (FFR) values after percutaneous coronary intervention (PCI) carry a worse prognosis than high post-PCI FFR values. Therefore, the ability to predict post-PCI FFR might play an important role in procedural planning. Post-PCI FFR values can now be computed from pre-PCI coronary computed tomography angiography (CTA) using the fractional flow reserve derived from coronary computed tomography angiography revascularization planner (FFR CT Planner)., Objectives: The aim of this study was to validate the accuracy of the FFR CT Planner., Methods: In this multicenter, investigator-initiated, prospective study, patients with chronic coronary syndromes and significant lesions based on invasive FFR ≤0.80 were recruited. The FFR CT Planner was applied to the fractional flow reserve derived from coronary computed tomography angiography (FFR CT ) model, simulating PCI. The primary objective was the agreement between the predicted post-PCI FFR by the FFR CT Planner and measured post-PCI FFR. Accuracy of the FFR CT Planner's luminal dimensions was assessed by using post-PCI optical coherence tomography as the reference., Results: Overall, 259 patients were screened, with 120 patients (123 vessels) included in the final analysis. The mean patient age was 64 ± 9 years, and 24% had diabetes. Measured FFR post-PCI was 0.88 ± 0.06, and the FFR CT Planner FFR was 0.86 ± 0.06 (mean difference: 0.02 ± 0.07 FFR unit; limits of agreement: -0.12 to 0.15). Optical coherence tomography minimal stent area was 5.60 ± 2.01 mm 2 , and FFR CT Planner minimal stent area was 5.0 ± 2.2 mm 2 (mean difference: 0.66 ± 1.21 mm 2 ; limits of agreement: -1.7 to 3.0). The accuracy and precision of the FFR CT Planner remained high in cases with focal and diffuse disease and with low and high calcium burden., Conclusions: The FFR CT -based technology was accurate and precise for predicting FFR after PCI. (Precise Percutaneous Coronary Intervention Plan Study [P3]; NCT03782688)., Competing Interests: Funding Support and Author Disclosures The study was sponsored by the Cardiac Research Institute Aalst with unrestricted grants from HeartFlow and Cardiopath. Drs Sonck and Munhoz have received research grants provided by the Cardiopath PhD program. Dr De Bruyne has received consultancy fees from Boston Scientific and Abbott Vascular; research grants from Coroventis Research, Pie Medical Imaging, CathWorks, Boston Scientific, Siemens, HeartFlow, and Abbott Vascular; and owns equity in Siemens, GE, Philips, HeartFlow, Edwards LifeSciences, Bayer, Sanofi, and Celyad. Dr Collet has received research grants from Biosensor, Coroventis Research, Medis Medical Imaging, Pie Medical Imaging, CathWorks, Boston Scientific, Siemens, HeartFlow, and Abbott Vascular; and consultancy fees from HeartFlow, OpSens, Abbott Vascular, and Philips Volcano. Dr Ko has received consulting fees from Canon Medical, Abbott, and Medtronic. Dr Mizukami has received consulting fees from Zeon Medical and HeartFlow; and speaker fees from Abbott Vascular. Dr Heggermont reports that Cardiac Research Institute Aalst receives consultancy fees on his behalf from Boston Scientific, Abbott Vascular, MicroPort, Medtronic, Biotronik, and AstraZeneca. Dr Updegrove and Ms Collinsworth are employees of HeartFlow. Dr Leipsic is a consultant and reports holding stock options in Circle CVI and HeartFlow; and has received a research grant from GE and modest speaker fees from GE and Philips. Drs Norgaard and Møller Jensen have received unrestricted institutional research grants from Siemens and HeartFlow. Dr Otake has received research grants from Abbott Vascular; and speaker fees from HeartFlow and Abbott Vascular. Dr Ihdayhid has received consulting fees from Canon, Artrya Medical, and Boston Scientific. Dr Koo has received institutional research grants from HeartFlow. Dr Andreini has received research grants from GE Healthcare and Bracco. Dr Barbato has received speaker fees from Boston Scientific, Abbott Vascular, and GE. Dr Maeng has received advisory board and lecture fees from AstraZeneca, Bayer, Boehringer Ingelheim, Bristol Myers Squibb, Boston Scientific, and Novo Nordics; and research grants from Bayer and Philips Healthcare. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Background and Aims: Absolute coronary flow can be measured by intracoronary continuous thermodilution of saline through a dedicated infusion catheter (RayFlow®). A saline infusion rate at 15-20 mL/min induces an immediate, steady-state, maximal microvascular vasodilation. The mechanism of this hyperemic response remains unclear. We aimed to test whether local hemolysis is a potential mechanism of saline-induced coronary hyperemia., Methods: Twelve patients undergoing left and right catheterization were included. The left coronary artery and the coronary sinus were selectively cannulated. Absolute resting and hyperemic coronary flow were measured by continuous intracoronary thermodilution. Arterial and venous samples were collected from the coronary artery and the coronary sinus in five phases: baseline (BL); resting flow measurement (Rest, saline infusion at 10 mL/min); hyperemia (Hyperemia, saline infusion at 20 mL/min); post-hyperemia (Post-Hyperemia, 2 min after the cessation of saline infusion); and control phase (Control, during infusion of saline through the guide catheter at 30 mL/min)., Results: Hemolysis was visually detected only in the centrifugated venous blood samples collected during the Hyperemia phase. As compared to Rest, during Hyperemia both LDH (131.50 ± 21.89 U/dL [Rest] and 258.33 ± 57.40 U/dL [Hyperemia], p < 0.001) and plasma free hemoglobin (PFHb, 4.92 ± 3.82 mg/dL [Rest] and 108.42 ± 46.58 mg/dL [Hyperemia], p < 0.001) significantly increased in the coronary sinus. The percentage of hemolysis was significantly higher during the Hyperemia phase (0.04 ± 0.02% [Rest] vs 0.89 ± 0.34% [Hyperemia], p < 0.001)., Conclusions: Saline-induced hyperemia through a dedicated intracoronary infusion catheter is associated with hemolysis. Vasodilatory compounds released locally, like ATP, are likely ultimately responsible for localized microvascular vasodilation., (Copyright © 2022. Published by Elsevier B.V.)

Competing Interests: Funding Support and Author Disclosures Drs Paolisso, Bertolone, and Esposito are supported by a research grant from the CardioPaTh PhD Program. Dr De Bruyne has an institutional consulting relationship with Boston Scientific, Abbott Vascular, CathWorks, Siemens, GE Healthcare, and Coroventis Research; has received institutional research grants from Abbott Vascular, Coroventis Research, CathWorks, and Boston Scientific; and holds minor equities in Philips, Siemens, GE Healthcare, Edwards Life Sciences, HeartFlow, Opsens, and Celiad. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.

Background: Percutaneous coronary interventions (PCI) in calcified coronary artery lesions are associated with impaired stent expansion, higher rate of periprocedural complications and cardiac mortality. Lesion preparation using calcium modifying techniques such as Rotational Atherectomy (RA) or Intravascular Lithotripsy (IVL) has been advocated. Studies comparing these technologies are lacking. We aimed to compare in-stent pressure gradients, evaluated by vessel fractional flow reserve (vFFR), in calcific lesions treated using either RA or IVL., Methods: Patients undergoing either RA- or IVL-assisted PCI from two European centers were included. Propensity score matching (1:2) was performed to control for potential bias. Primary outcome was post-PCI in-stent pressure gradients calculated by vFFR (vFFRgrad). Secondary outcomes included the proportion of patients with complete functional revascularization defined as distal vFFR post-PCI (vFFRpost) ≥ 0.90., Results: From a cohort of 210 patients, 105 matched patients (70 RA and 35 IVL) were included. Pre-PCI vFFR did not differ between groups (0.65 ± 0.13 RA and 0.67 ± 0.11 IVL). After PCI, in-stent pressure gradients were significantly lower in the IVL group (0.032 ± 0.026 vs 0.043 ± 0.026 in the RA group, p = 0.024). The proportions of vessels with functional complete revascularization was similar between the two groups (32.9% vs. 37.1% in the RA and IVL group, respectively; p = 0.669)., Conclusions: Calcific lesions preparation with IVL is effective and resulted in lower in-stent pressure gradients compared to RA. Approximately one third of the patients undergoing PCI for a severely calcified lesion achieved functional revascularization with no difference between rotational RA and IVL., (Copyright © 2022. Published by Elsevier B.V.)

Background and Aims: Wall shear stress (WSS) has been associated with atherogenesis and plaque progression. The present study assessed the value of WSS analysis derived from conventional coronary angiography to detect lesions culprit for future myocardial infarction (MI)., Methods and Results: Three-dimensional quantitative coronary angiography (3DQCA), was used to calculate WSS and pressure drop in 80 patients. WSS descriptors were compared between 80 lesions culprit of future MI and 108 non-culprit lesions (controls). Endothelium-blood flow interaction was assessed by computational fluid dynamics (10.8 ± 1.41 min per vessel). Median time between baseline angiography and MI was 25.9 (21.9-29.8) months. Mean patient age was 70.3 ± 12.7. Clinical presentation was STEMI in 35% and NSTEMI in 65%. Culprit lesions showed higher percent area stenosis (%AS), translesional vFFR difference (ΔvFFR), time-averaged WSS (TAWSS) and topological shear variation index (TSVI) compared to non-culprit lesions (p < 0.05 for all). TSVI was superior to TAWSS in predicting MI (AUC-TSVI = 0.77, 95%CI 0.71-0.84 vs. AUC-TAWSS = 0.61, 95%CI 0.53-0.69, p < 0.001). The addition of TSVI increased predictive and reclassification abilities compared to a model based on %AS and ΔvFFR (NRI = 1.04, p < 0.001, IDI = 0.22, p < 0.001)., Conclusions: A 3DQCA-based WSS analysis was feasible and can identify lesions culprit for future MI. The combination of area stenoses, pressure gradients and WSS predicted the occurrence of MI. TSVI, a novel WSS descriptor, showed strong predictive capacity to detect lesions prone to cause MI., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Background: The role of change in fractional flow reserve derived from CT (FFR CT ) across coronary stenoses (ΔFFR CT ) in guiding downstream testing in patients with stable coronary artery disease (CAD) is unknown., Objectives: To investigate the incremental value of ΔFFR CT in predicting early revascularization and improving efficiency of catheter laboratory utilization., Materials: Patients with CAD on coronary CT angiography (CCTA) were enrolled in an international multicenter registry. Stenosis severity was assessed as per CAD-Reporting and Data System (CAD-RADS), and lesion-specific FFR CT was measured 2 ​cm distal to stenosis. ΔFFR CT was manually measured as the difference of FFR CT across visible stenosis., Results: Of 4730 patients (66 ​± ​10 years; 34% female), 42.7% underwent ICA and 24.7% underwent early revascularization. ΔFFR CT remained an independent predictor for early revascularization (odds ratio per 0.05 increase [95% confidence interval], 1.31 [1.26-1.35]; p ​< ​0.001) after adjusting for risk factors, stenosis features, and lesion-specific FFR CT . Among the 3 models (model 1: risk factors ​+ ​stenosis type and location ​+ ​CAD-RADS; model 2: model 1 ​+ ​FFR CT ; model 3: model 2 ​+ ​ΔFFR CT ), model 3 improved discrimination compared to model 2 (area under the curve, 0.87 [0.86-0.88] vs 0.85 [0.84-0.86]; p ​< ​0.001), with the greatest incremental value for FFR CT 0.71-0.80. ΔFFR CT of 0.13 was the optimal cut-off as determined by the Youden index. In patients with CAD-RADS ≥3 and lesion-specific FFR CT ≤0.8, a diagnostic strategy incorporating ΔFFR CT >0.13, would potentially reduce ICA by 32.2% (1638-1110, p ​< ​0.001) and improve the revascularization to ICA ratio from 65.2% to 73.1%., Conclusions: ΔFFR CT improves the discrimination of patients who underwent early revascularization compared to a standard diagnostic strategy of CCTA with FFR CT , particularly for those with FFR CT 0.71-0.80. ΔFFR CT has the potential to aid decision-making for ICA referral and improve efficiency of catheter laboratory utilization., Competing Interests: Declaration of competing interest This study was supported by HeartFlow, Inc., Redwood City, California, via individual Clinical Study Agreements with each enrolling institution and with the Duke Clinical Research Institute (DCRI) for Core Laboratory activities and Clinical Event Committee adjudication of adverse events. Dr. Leipsic receives institutional grants to provide core lab services to Edwards Life Sciences, Medtronic and is a consultant to Circle CVI and HeartFlow. Dr. Fairbairn is on the Speakers Bureau for HeartFlow. Dr. Nørgaard has received unrestricted institutional research grants from Siemens and HeartFlow. Dr. Berman has received unrestricted research support from HeartFlow. Dr. Chinnaiyan has received institutional grants from HeartFlow. Dr. Hurwitz-Koweek is on the Speakers Bureau for HeartFlow; and has unrestricted grant funding from Siemens and HeartFlow. Dr. Pontone is a consultant for GE Healthcare; and has research grants from GE Healthcare and HeartFlow. Dr. Rabbat has received institutional grants from HeartFlow. Dr. Mullen is an employee of HeartFlow. Dr. Rogers is an employee of and has equity in HeartFlow. Dr. Bax has received unrestricted research grants from Edwards Lifescience, Medtronic, Boston Scientific, Biotronik, and GE Healthcare; and is on the Speakers Bureau with Abbott. Dr. Douglas receives an institutional research grant from HeartFlow. Dr. Patel has received grants from HeartFlow, Jansen, Bayer, AstraZeneca, and NHLBI; and has served as a consultant for Jansen, Bayer, AstraZeneca, Genzyme, and Merck. Dr. Nieman reports institutional research support from Siemens Healthineers, Bayer, HeartFlow Inc. and is a consultant to Siemens Medical Solutions USA. Dr. Ihdayhid is supported by the National Health and Medical Research Council of Australia and National Heart Foundation Scholarships; and has received honoraria from Canon Medical and Boston Scientific. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Objectives: The aim of this study was to determine the safety of selective intracoronary hypothermia during primary percutaneous coronary intervention (PPCI) in patients with anterior ST-segment elevation myocardial infarction (STEMI)., Background: Selective intracoronary hypothermia is a novel treatment designed to reduce myocardial reperfusion injury and is currently being investigated in the ongoing randomized controlled EURO-ICE (European Intracoronary Cooling Evaluation in Patients With ST-Elevation Myocardial Infarction) trial (NCT03447834). Data on the safety of such a procedure during PPCI are still limited., Methods: The first 50 patients with anterior STEMI treated with selective intracoronary hypothermia during PPCI were included in this analysis and compared for safety with the first 50 patients randomized to the control group undergoing standard PPCI. In-hospital mortality, occurrence of rhythm or conduction disturbances, stent thrombosis, onset of heart failure during the procedure, and subsequent hospital admission were assessed., Results: In-hospital mortality was 0%. One patient in both groups developed cardiogenic shock. Atrial fibrillation occurred in 0 and 3 patients (P = 0.24), and ventricular fibrillation occurred in 5 and 3 patients (P = 0.72) in the intracoronary hypothermia group and control group, respectively. Stent thrombosis occurred in 2 patients in the intracoronary hypothermia group; 1 instance was intraprocedural, and the other occurred following interruption of dual-antiplatelet therapy consequent to an intracranial hemorrhage 6 days after enrollment. No stent thrombosis was observed in the control group (P = 0.50)., Conclusions: Selective intracoronary hypothermia during PPCI in patients with anterior STEMI can be implemented within the routine of PPCI and seems to be safe. The final safety results will be reported at the end of the trial., Competing Interests: Funding Support and Author Disclosures Dr Engstrøm has received personal fees from Abbott and Bayer, outside the submitted work. Dr Oldroyd has received employee fees from Biosensors International, outside the submitted work. Dr Karamasis has received personal fees from Abbott Vascular, outside the submitted work. Dr Keeble has received grants from Abbott Vascular, Zoll, and AstraZeneca, outside the submitted work. Dr De Bruyne has received grant support from Abbott, Boston Scientific, Biotronik, and St. Jude Medical; has received consulting fees from St. Jude Medical, Opsens, and Boston Scientific, outside the submitted work; and is a shareholder in Siemens, GE, Bayer, Philips, HeartFlow, Edwards Lifesciences, and Ceyliad. Dr Berry has received grants from Abbott Vascular, AstraZeneca, Boehringer Ingelheim, Coroventis, GlaxoSmithKline, HeartFlow, Medyria, Neovasc, Novartis, Siemens Healthcare, and Menarini, outside the submitted work; and is supported by research funding from the British Heart Foundation (RE/18/6134217). Dr Pijls has received personal fees from Abbott and Opsens; holds equity in Philips, ASML, HeartFlow and GE Healthcare; and has received institutional research grants from Abbott and Hexacath. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2021 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Coronary computed tomography angiography (CCTA) is now an established tool in the diagnostic work-up of patients suspected to have coronary artery disease. Yet, its usefulness beyond this phase has not been fully explored. The current review focuses on the implementation of CCTA as a tool to plan and guide coronary interventions in the catheterization laboratory. Specifically, we explore the potential of CCTA to improve patient selection for percutaneous revascularization, provide the rationale for better resource use, and present a novel approach to incorporate 3-dimensional CT guidance for percutaneous coronary interventions., Competing Interests: Funding Support and Author Disclosures Dr. Collet has received research grants from Biosensors, Heart Flow Inc., and Abbott Vascular; and consultancy fees from Opsens, Boston Scientific, HeartFlow Inc., and Philips Volcano. Dr. Sonck has received research grants provided by the Cardiopath PhD program. Dr. Kitslaar is an employee of Medis Medical Imaging Systems. Dr. De Bruyne has received institutional consultancy fees and/or research grants from Abbott, Boston Scientific, and Biotronic. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2021 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Morphological evaluation of coronary lesion length is a paramount step during invasive assessment of coronary artery disease. Likewise, the extent of epicardial pressure losses can be measured using longitudinal vessel interrogation with fractional flow reserve (FFR) pullbacks. We aimed to quantify the mismatch in lesion length between morphological (based on quantitative coronary angiography, QCA, and optical coherence tomography, OCT) and functional evaluations., Methods: This is a prospective and multicenter study of patients evaluated by QCA, OCT and motorized fractional flow reserve pullbacks (mFFR). The difference in lesion length between the functional and anatomical evaluations was referred to as FAM., Results: 117 patients (131 vessels) were included. Median lesion length derived from angiography was 16.05 mm [11.40-22.05], from OCT was 28.00 mm [16.63-38.00] and from mFFR 67.12 mm [25.38-91.37]. There was no correlation between QCA and mFFR lesion length (r = 0.124, 95% CI -0.168-0.396, p = 0.390). OCT lesion length did correlate with mFFR (r = 0.469, 95% CI 0.156-0.696, p = 0.004). FAM was strongly associated with the improvement in vessel conductance with percutaneous coronary intervention (PCI), higher mismatch was associated with lower post-PCI FFR., Conclusions: Lesion length assessment differs between morphological and functional evaluations. The morphological-functional mismatch in lesion length is frequent, and influences the results of PCI in terms of post-PCI FFR. Integration of the extent of pressure losses provides clinically relevant information that may be useful for clinical decision-making concerning revascularization strategy., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Background: Coronary microvascular dysfunction is a powerful prognostic factor in patients with coronary artery disease. We investigated the role of reactive digital hyperemia peripheral arterial tonometry (RH-PAT) as a non-invasive tool to identify patients with impaired coronary microvasculature., Methods: Patients undergoing elective coronary angiography were consecutively assessed for peripheral microvascular endothelial function before coronary angiography: both the Reactive Hyperemic Index (RHI) and the Framingham reactive hyperemic index (Endoscore) were measured. During coronary angiography, the Index of microvascular resistance (IMR) was measured in all patients, and an IMR value > 25 identified patients with coronary microvascular impairment., Results: A total of 47 patients with chronic coronary syndromes candidate to coronary angiography were included. Those with coronary microvascular impairment (n = 18 [38%]) presented with significantly lower RHI (1.68 ± 0.38 vs. 1.94 ± 0.93, p = 0.04) and Endoscore 0.50 ± 0.23 vs. 0.64 ± 0.23, p = 0.04) values as compared with patients with preserved coronary microvasculature. A significant relationship was observed between IMR with both RHI (r = 0.35, p = 0.02) and Endoscore (r = 0.34, p = 0.02). At the multivariable analysis, RHI and Endoscore were the only independent predictors of an IMR > 25., Conclusions: Our study demonstrates that digital reactive hyperemia indexes are lower in patients with high IMR values, suggesting a role for RH-PAT as non-invasive tool for identifying patients with coronary microvascular impairment., Competing Interests: Declaration of competing interest None., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Coronary microvascular dysfunction is a highly prevalent condition in both obstructive and nonobstructive coronary artery disease. Intracoronary thermodilution is a promising technique to investigate coronary microvascular (dys)function in vivo and to assess its most important metric: microvascular resistance. Here, the authors provide a practical review of bolus and continuous thermodilution for the measurement of coronary flow and microvascular resistance. The authors describe the basic principles of indicator-dilution theory and of coronary thermodilution and detail the practicalities of their application in the catheterization laboratory. Finally, the authors discuss contemporary clinical applications of coronary thermodilution-based microvascular assessment in humans and future perspectives., Competing Interests: Funding Support and Author Disclosures Drs. Kodeboina, Fournier, Di Gioia, and Sonk are supported by a research grant from CardioPaTh. Dr. Di Gioia is supported by the STAR program of Compagnia di San Paolo. Dr. Collet has received institutional consultancy fees from HeartFlow and Philips Volcano. Dr. van ’t Veer has received speaker fees from Abbott. Dr. Pijls has received institutional research grants from Abbott and Hexacath; has received consultancy fees from Abbott, Opsens, and GE; and holds minor equity positions in Philips, ASML, and HeartFlow. Dr. De Bruyne has received institutional consulting fees from Abbott Vascular, Boston Scientific, Opsens, and Siemens; has received institutional grant support from Abbott Vascular, Boston Scientific, Biotronik, and Medtronic; and holds equity positions in Philips, Siemens, GE, Bayer, HeartFlow, Edwards Lifesciences, and Ceyliad. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2021. Published by Elsevier Inc.)

Background: CT coronary angiography (CTA) with Fractional Flow Reserve as determined by CT (FFR CT ) is a safe alternative to invasive coronary angiography. A negative FFR CT has been shown to have low cardiac event rates compared to those with a positive FFR CT . However, the clinical utility of FFR CT according to age is not known., Methods: Patients' in the ADVANCE (Assessing Diagnostic Value of Non-invasive FFRCT in Coronary Care) registry, were stratified into those ≥65 or <65 years of age. The impact of FFR CT on clinical decision-making, as assessed by patient age, was determined by evaluating patient management using CTA results alone, followed by site investigators submitting a report on the treatment plan based upon the newly provided FFR CT data. Outcomes at 1-year post CTA were assessed, including major adverse cardiovascular events (myocardial infarction, all-cause mortality or unplanned hospitalization for ACS leading to revascularisation) and total revascularisation. Positive FFR CT was deemed to be ​≤ ​0.8., Results: FFR CT was calculated in 1849 (40.6%) subjects aged <65 and 2704 (59.4%) ​≥ ​65 years of age. Subjects ≥65 years were more likely to have anatomic obstructive disease on CTA (≥50% stenosis), compared to those aged <65 (69.7% and 73.2% respectively, p ​= ​0.008). There was a similar graded increase in recommended and actual revascularisation with either CABG or PCI, with declining FFR CT strata for subjects above and below the age of 65. MACE and revascularisation rates were not significantly different for those ​≥ ​or <65, regardless of FFR CT positivity or stenosis severity <50% or ≥50%. With a negative FFR CT result, and anatomical stenosis ≥50%, those ​≥ ​and <65 years of age, had similar rates of MACE (0.2% for both, p ​= ​0.1) and revascularisation (8.7% and 10.4% respectively p ​= ​0.4). Logistic regression analysis, with age as a continuous variable, and adjustment for Diamond Forrester Risk, baseline FFR CT and treatment (CABG, PCI, medical therapy), indicated a statistically significant, but small increase in the odds of a MACE event with increasing age (OR 1.04, 95% CI 1.006-1.08, p ​= ​0.02). Amongst patients with a FFR CT > 0.80, there was no effect of age on the odds of revascularisation., Conclusion: The findings of this study point to a low risk of MACE events or need for revascularisation in those aged ​≥ ​or <65 with a FFR CT >0.80, despite the higher incidence of anatomic obstructive CAD in those ≥65 years. The findings show the clinical usefulness and outcomes of FFR CT are largely constant regardless of age., (Copyright © 2020 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.)

Background: The ADVANCE registry is a large prospective study of outcomes and resource utilization in patients undergoing coronary computed tomography angiography (CCTA) and CT-based fractional flow reserve (FFR CT ). As experience with new technologies and practices develops over time, we investigated temporal changes in the use of FFR CT within the ADVANCE registry., Methods: 5083 patients with coronary artery disease (CAD) on CCTA were prospectively enrolled in the ADVANCE registry and were divided into 3 equally sized cohorts based on the temporal order of enrollment per site. Demographics, CCTA and FFR CT findings, and clinical outcomes through 1-year follow-up, were recorded and compared between tertiles., Results: The number of patients with a ≥70% stenosis on CCTA was similar over time (33.6%, 30.9%, and 33.8% for cohort 1-3). The rate of positive FFR CT ≤0.80 was higher for cohorts 2 (67.3%) and 3 (74.6%) than for cohort 1 (57.1%, p < 0.001). Invasive FFR rates decreased from 25.8% to 22.4% between cohort 1 and 3 (p = 0.023). Moreover, patients with a FFR CT ≤0.80 were less frequently referred for invasive coronary angiography (ICA) (from 62.9% to 52.9%, p < 0.001), and underwent fewer revascularizations between cohort 1 and 3 (from 41.9% to 32.0%, p < 0.001). The prevalence of major events was low (1.2%) and similar between cohorts., Conclusions: Growing experience with FFR CT improved the likelihood of identifying hemodynamically significant CAD and safely reduced the need for ICA and revascularization in patients with anatomically significant disease even in the instance of an abnormal FFR CT., Competing Interests: Declaration of competing interest Dr. Nous has received travel sponsorship from HeartFlow. Dr. Fairbairn has served on the Speakers Bureau for HeartFlow. Dr. Nørgaard has received unrestricted institutional research grants from Siemens and HeartFlow. Dr. Berman has received unrestricted research support from HeartFlow. Dr. Hurwitz-Koweek has received research support and fee as speaker from HeartFlow and Siemens. Dr. Pontone has received research grant and/or fee as speaker from GE Healthcare, Bracco, and HeartFlow. Dr. Budde has institutional research support from HeartFlow and Siemens Healthineers. Dr. Sonck has received research grant support from the Cardiopath PhD program. Dr. Rabbat has served as a consultant for HeartFlow. Dr. Mullen is an employee of and owns equity in HeartFlow. Dr. De Bruyne has received consulting fees from Abbott, Opsens, and Boston Scientific; and is a shareholder for Siemens, GE Healthcare, Bayer, Philips, HeartFlow, Edwards Lifesciences, and Sanofi. Dr. Rogers is employee of and owns equity in HeartFlow. Dr. Leipsic has served as a consultant for and owns stock options in Circle CVI and HeartFlow. Dr. Patel has received research grants from HeartFlow, Bayer, Janssen, and the National Heart, Lung, and Blood Institute; and has served on the advisory board for HeartFlow, Bayer, and Janssen. Dr. Nieman has received institutional research support from Siemens Healthineers, HeartFlow, GE Healthcare, and Bayer Healthcare. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2020 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.)

Background: Graft occlusion after coronary artery bypass graft surgery (CABG) has been associated with native coronary artery competitive flow., Objectives: The present study aims to characterize the functional progression of coronary artery disease (CAD) in native vessels after CABG, and to assess the relationship between preoperative FFR as derived from angiography and graft occlusion., Methods: Multicenter study of consecutive patients undergoing CABG between 2013 and 2018, in whom a follow-up angiogram had been performed. Serial vessel-fractional flow reserve (vFFR) analyses were obtained in each major native coronary vessel before and after CABG, excluding post-anastomotic segments and graft conduits., Results: In 73 patients, serial angiograms were suitable for vFFR analysis, including 118 grafted (86 arterial and 32 saphenous grafts) and 64 non-grafted vessels. The median time between CABG and follow-up angiography was 2.4 years [IQR 1.5, 3.3]. Functional CAD progression, by means of decline in vFFR, was observed in grafted but not in non-grafted vessels (delta vFFR in grafted vessels 0.10 [IQR 0.05, 0.18] vs. 0.01 [IQR -0.01, 0.03], in non-grafted vessels, p < 0.001). Preoperative vFFR predicted graft occlusion (AUC: 0.66, 95% CI 0.52 to 0.80, p = 0.031)., Conclusions: In patients undergoing CABG, preoperative vFFR derived from conventional angiograms without use of pressure wire was able to predict graft occlusion. Graft occlusion was more frequent in vessels with high vFFR values. Grafted native coronary vessels exhibited accelerated functional CAD progression, whereas in non-grafted native coronaries the functional status remained unchanged., Competing Interests: Declaration of competing interest CC report receiving research grants from Biosensor, Heart Flow Inc. and Abbott Vascular; and consultancy fees from Heart Flow Inc. and Philips Volcano. JS reports a research grant provided by Cardiopath Ph.D program. TM report receiving consultancy fees from Heart Flow Inc. EM reports institutional grant support from Abbott Vascular, Boston Scientific, and Biotronik. DA reports institutional fees as a speaker and clinical research grants from GE, Bracco, and Heartflow. BDB reports receiving consultancy fees on his behalf from Boston Scientific and Abbott Vascular. The other authors have nothing to disclose. This study was supported by the VZW Cardiovascular Research Centre, Aalst, Belgium., (Copyright © 2020. Published by Elsevier B.V.)

The identification of factors determining whether a lesion progresses, destabilizes or becomes quiescent remains a challenge. Wall or endothelial shear stress (WSS or ESS, respectively), the frictional force acting on the lumen wall, is strongly associated with changes in the natural history of lesions. Several clinical intravascular imaging studies have shown a clear link between disturbed flow, typically characterized by low WSS, and plaque growth. In support of these studies, in-vitro experiments of shear stress have identified several mechanisms promoting atherosclerosis. More recently, the relationship between WSS and major adverse cardiac events has been explored. Improvements in coronary computed tomography angiography (CCTA) image resolution and quality has allowed for the calculation of WSS from CT. In this review, we provide an introduction to WSS, highlight important human and animal intravascular-based WSS studies, and discuss CT-based WSS studies to date. Finally, we discuss future directions of CCTA and WSS computation., (Copyright © 2020. Published by Elsevier Inc.)

Objectives: This study sought to compare next-generation cobalt-chromium-based titanium-nitride-oxide (TiNO)-coated stents with a platinum-chromium-based biodegradable polymer everolimus-eluting stent (EES) in patients with acute coronary syndrome (ACS)., Background: Previous generation TiNO-coated stents showed acceptable performance in patients with ACS., Methods: In a multicenter, randomized trial, we randomly assigned 1,491 ACS patients (2:1) to receive either a TiNO-coated stent (n = 989) or EES (n = 502). The primary endpoint was the rate of a composite of cardiac death, myocardial infarction (MI), or ischemia-driven target lesion revascularization at 12-month follow-up. The co-primary endpoint was a composite of cardiac death, MI, or major bleeding at 18 months., Results: A primary endpoint event occurred in 6.3% of patients in the TiNO-coated stent group versus in 7.0% in the EES group (hazard ratio: 0.93; 95% confidence interval: 0.71 to 1.22; p = 0.66 for superiority; p < 0.001 for noninferiority). A co-primary endpoint event occurred in 3.7% of the patients in the TiNO group and in 7.8% in the EES group (hazard ratio: 0.64; 95% confidence interval: 0.51 to 0.80; p = 0.001). TiNO-coated stents were associated with lower rates of cardiac death (0.6% vs. 2.6%; p = 0.002) and MI (2.2% vs. 5.0%; p = 0.007) at 18 months of follow-up. Rates of target lesion revascularization were not significantly different at 18 months (5.8% vs. 4.4%; p = 0.27)., Conclusions: In patients with ACS, cobalt-chromium-based TiNO-coated stents were noninferior to platinum-chromium-based biodegradable polymer EES for major cardiac events at 12 months, and were superior for the co-primary endpoint of cardiac death, MI, and bleeding at 18 months. (Comparison of Titanium-Nitride-Oxide-Coated Bio-Active-Stent (Optimax™) to the Drug (Everolimus) -Eluting Stent (Synergy™) in Acute Coronary Syndrome [TIDES-ACS]; NCT02049229)., (Copyright © 2020 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)