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Purpose of Review: This review evaluates the emerging role of the pullback pressure gradient (PPG) as a standardized metric for assessing coronary artery disease (CAD) patterns and its implications for clinical decision-making when managing patients undergoing percutaneous coronary interventions (PCIs). By integrating PPG with existing physiological assessments, this review highlights the potential benefits of PPG in predicting treatment outcomes and refining therapeutic strategies for CAD., Recent Findings: Recent studies, particularly the PPG Global study have demonstrated a strong correlation between PPG values and post-PCI outcomes, revealing that focal disease is associated with improved fractional flow reserve (FFR) and lower rates of adverse events than vessels with diffuse disease (low PPG). Additionally, PPG has been linked to specific atherosclerotic plaque characteristics, indicating its utility in identifying high-risk plaques. The integration of PPG with advanced imaging techniques further enhances the understanding of CAD patterns and their implications for treatment planning., Summary: The PPG represents a significant advancement in the management of CAD, providing a reproducible and objective assessment of coronary artery disease patterns that can inform clinical decision-making. As research continues to explore the relationship among PPG, atherosclerotic characteristics, and patient outcomes, its integration into routine practice is expected to improve the effectiveness of PCI and optimize patient management strategies. Future studies are warranted to establish specific PPG thresholds and further investigate its potential in identifying vulnerable plaques and guiding treatment decisions., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc.)

Background: Angiography-derived fractional flow reserve (virtual FFR) has shown excellent diagnostic performance compared with wire-based FFR. However, virtual FFR pullback curves have not been validated yet., Objectives: To validate the accuracy of virtual FFR pullback curves compared to wire-based FFR pullbacks and to assess their clinical utility using patient-reported outcomes., Methods: Pooled analysis of two prospective studies, including patients with hemodynamically significant (FFR ≤ 0.80) coronary artery disease (CAD). Virtual and wire-based FFR pullbacks were compared to assess the accuracy of virtual pullbacks to characterize CAD as focal or diffuse. Pullbacks were analyzed visually and quantitatively using the pullback pressure gradient (PPG). Patients underwent PCI, and the Seattle Angina Questionnaire (SAQ) was administered at 3-month follow-up., Results: A total of 298 patients (300 vessels) with both virtual and wire-based pullbacks who underwent PCI were included in the analysis. The mean age was 61.8 ± 8.8, and 15% were female. The agreement on the visual adjudication of the CAD pattern was fair (Cohen's Kappa: 0.31, 95% confidence interval: 0.18-0.45). The mean PPG were 0.65 ± 0.18 from virtual pullbacks and 0.65 ± 0.13 from wire-based pullbacks (r = 0.68, mean difference 0, limits of agreement -0.27 to 0.28). At follow-up, patients with high virtual PPG (>0.67) had higher SAQ angina frequency scores (i.e., less angina) than those with low virtual PPG (SAQ scores 92.0 ± 14.3 vs. 85.5 ± 23.1, p = 0.022)., Conclusion: Virtual FFR pullback curves showed moderate agreement with wire-based FFR pullbacks. Nonetheless, patients with focal disease based on virtual PPG reported greater improvement in angina after PCI., (© 2024 Wiley Periodicals LLC.)

Background: Diffuse coronary artery disease affects the safety and efficacy of percutaneous coronary intervention (PCI). Pathophysiologic coronary artery disease patterns can be quantified using fractional flow reserve (FFR) pullbacks incorporating the pullback pressure gradient (PPG) calculation. This study aimed to establish the capacity of PPG to predict optimal revascularization and procedural outcomes., Methods: This prospective, investigator-initiated, single-arm, multicenter study enrolled patients with at least one epicardial lesion with an FFR ≤0.80 scheduled for PCI. Manual FFR pullbacks were used to calculate PPG. The primary outcome of optimal revascularization was defined as an FFR ≥0.88 after PCI., Results: A total of 993 patients with 1044 vessels were included. The mean FFR was 0.68±0.12, PPG 0.62±0.17, and the post-PCI FFR was 0.87±0.07. PPG was significantly correlated with the change in FFR after PCI (r=0.65 [95% CI, 0.61-0.69]; P <0.001) and demonstrated excellent predictive capacity for optimal revascularization (area under the receiver operating characteristic curve, 0.82 [95% CI, 0.79-0.84]; P <0.001). FFR alone did not predict revascularization outcomes (area under the receiver operating characteristic curve, 0.54 [95% CI, 0.50-0.57]). PPG influenced treatment decisions in 14% of patients, redirecting them from PCI to alternative treatment modalities. Periprocedural myocardial infarction occurred more frequently in patients with low PPG (<0.62) compared with those with focal disease (odds ratio, 1.71 [95% CI, 1.00-2.97])., Conclusions: Pathophysiologic coronary artery disease patterns distinctly affect the safety and effectiveness of PCI. PPG showed an excellent predictive capacity for optimal revascularization and demonstrated added value compared with an FFR measurement., Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT04789317., Competing Interests: Dr Collet reports receiving research grants from Biosensors, Coroventis Research, Medis Medical Imaging, Pie Medical Imaging, CathWorks, Boston Scientific, Siemens, HeartFlow, and Abbott Vascular; consultancy fees from HeartFlow, OpSens Medical, Abbott Vascular, and Philips Volcano; and has patents pending on diagnostic methods for coronary artery disease. Dr Munhoz reports a research grant provided by the CardioPath PhD programme and speaker fees from Abbott Vascular. Dr Mizukami reports receiving research grants from Boston Scientific and speaker fees from Abbott Vascular, CathWorks, and Boston Scientific. Dr Matsuo has received consulting fees from Kaneka and Zeon and speaker’s fees from Abbott Medical Japan, Boston Scientific, Philips, and Amgen. Dr Ko has received consulting fees from Canon Medical, Abbott, and Medtronic. Dr Biscaglia received research grants provided by Sahajanand Medical Technologies, Medis Medical Imaging, Eukon Srl, Siemens Healthineers, General Electric Healthcare, and Insight Lifetech. Dr Engstrøm reports speaker and advisory board fees from Abbott, Boston Scientific, and Novo Nordisk. Dr Leone reports receiving consultancy fees from Abbott and honoraria for sponsored symposia from Abbott, Medtronic, and Abiomed. Dr Fearon receives institutional research support from Abbott, Boston Scientific, and Medtronic and has consulting relationships with CathWorks and Siemens and stock options from HeartFlow. Dr Christiansen has received consulting fees from Abbott Medical Denmark A/S. Dr Yong has received minor honoraria from Abbott Vascular and research grants from Abbott Vascular and Philips. Dr Escaned is supported by the Intensification of Research Activity project INT22/00088 from the Spanish Instituto de Salud Carlos III and received speaker and advisory board member fees from Abbott and Philips. Dr Storozhenko reports a grant provided by the EAPCI Fellowship Programme. Dr West is an employee of Abbott Vascular. Dr De Potter is a paid consultant for Biosense Webster and receives grant support (institutional) and consultancy fees (institutional) from Abbott. Dr Berry receives research funding from the British Heart Foundation (grants RE/18/6134217, BHF/FS/17/26/32744, and PG/19/28/34310) and is employed by the University of Glasgow, which holds consultancy and research agreements for his work with Abbott Vascular, AstraZeneca, Boehringer Ingelheim, Coroventis Research, GlaxoSmithKline, HeartFlow, Menarini, Novartis, Servier, Siemens Healthcare, and Valo Health. Dr Collison has received consulting fees from Abbott. Dr Johnson has received consultancy or speaker fees from Abbott Vascular, Boston Scientific, Medtronic, Shockwave, and Terumo, and research grants from Abbott Vascular. Dr Amano reports receiving lecture fees from Astellas Pharma, Astra Zeneca, Bayer, Daiichi Sankyo, and Bristol Myers Squibb. Dr Perera has received research grant support from Abbott Vascular, HeartFlow, and Philips. Dr Jeremias has received consulting fees from Canon Medical, Artrya Medical, and Boston Scientific. Dr Ali reports institutional grant support from Abbott, Abiomed, Acist, Amgen, Boston Scientific, CathWorks, Canon Medical, Conavi, HeartFlow, Inari, Medtronic, the US National Institutes of Health, Nipro, OpSens Medical, Medis, Philips, Shockwave, Siemens, SpectraWAVE, and Teleflex; consulting fees from Abiomed, Astra Zeneca, Boston Scientific, CathWorks, OpSens Medical, Philips, and Shockwave; and equity in Elucid, Lifelink, SpectraWAVE, Shockwave, and VitalConnect. Dr Pijls has received research grants from Abbott and Hexacath; consultancy fees from Abbott, GE, Philips, and HeartFlow; and has equity in General Electric, Philips, and HeartFlow. Dr De Bruyne reports receiving consultancy fees from Boston Scientific and Abbott and research grants from Coroventis Research, Pie Medical Imaging, CathWorks, Boston Scientific, Siemens, HeartFlow, and Abbott Vascular. Dr Johnson received internal funding from the Weatherhead PET Center for Preventing and Reversing Atherosclerosis; has received significant institutional research support from St Jude Medical (CONTRAST [Can Contrast Injection Better Approximate FFR Compared to Pure Resting Physiology?; URL: https://www.clinicaltrials.gov; Unique identifier: NCT02184117]) and Philips Volcano (DEFINE-FLOW [Combined Pressure and Flow Measurements to Guide Treatment of Coronary Stenoses; URL: https://www.clinicaltrials.gov; Unique identifier: NCT02328820]) for other studies using intracoronary pressure and flow sensors; has an institutional licensing agreement with Boston Scientific for the smart-minimum FFR algorithm (now commercialized under 510[k] K191008); and has patents pending on diagnostic methods for quantifying aortic stenosis and TAVI physiology and on methods to correct pressure tracings from fluid-filled catheters.

Objective: To assess the accuracy of a virtual stenting tool based on coronary CT angiography (CCTA) and fractional flow reserve (FFR) derived from CCTA (FFR CT Planner) across different levels of image quality., Materials and Methods: Prospective, multicenter, single-arm study of patients with chronic coronary syndromes and lesions with FFR ≤ 0.80. All patients underwent CCTA performed with recent-generation scanners. CCTA image quality was adjudicated using the four-point Likert scale at a per-vessel level by an independent committee blinded to the FFR CT Planner. Patient- and technical-related factors that could affect the FFR CT Planner accuracy were evaluated. The FFR CT Planner was applied mirroring percutaneous coronary intervention (PCI) to determine the agreement with invasively measured post-PCI FFR., Results: Overall, 120 patients (123 vessels) were included. Invasive post-PCI FFR was 0.88 ± 0.06 and Planner FFR CT was 0.86 ± 0.06 (mean difference 0.02 FFR units, the lower limit of agreement (LLA) - 0.12, upper limit of agreement (ULA) 0.15). CCTA image quality was assessed as excellent (Likert score 4) in 48.3%, good (Likert score 3) in 45%, and sufficient (Likert score 2) in 6.7% of patients. The FFR CT Planner was accurate across different levels of image quality with a mean difference between FFR CT Planner and invasive post-PCI FFR of 0.02 ± 0.07 in Likert score 4, 0.02 ± 0.07 in Likert score 3 and 0.03 ± 0.08 in Likert score 2, p = 0.695. Nitrate dose ≥ 0.8mg was the only independent factor associated with the accuracy of the FFR CT Planner (95%CI - 0.06 to - 0.001, p = 0.040)., Conclusion: The FFR CT Planner was accurate in predicting post-PCI FFR independent of CCTA image quality., Clinical Relevance Statement: Being accurate in predicting post-PCI FFR across a wide spectrum of CT image quality, the FFR CT Planner could potentially enhance and guide the invasive treatment. Adequate vasodilation during CT acquisition is relevant to improve the accuracy of the FFR CT Planner., Key Points: • The fractional flow reserve derived from coronary CT angiography (FFR CT ) Planner is a novel tool able to accurately predict fractional flow reserve after percutaneous coronary intervention. • The accuracy of the FFR CT Planner was confirmed across a wide spectrum of CT image quality. Nitrates dose at CT acquisition was the only independent predictor of its accuracy. • The FFR CT Planner could potentially enhance and guide the invasive treatment., (© 2023. The Author(s), under exclusive licence to European Society of Radiology.)

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: Following percutaneous coronary intervention (PCI), optical coherence tomography provides prognosis information. The pullback pressure gradient is a novel index that discriminates focal from diffuse coronary artery disease based on fractional flow reserve pullbacks. We sought to investigate the association between coronary artery disease patterns, defined by coronary physiology, and optical coherence tomography after stent implantation in stable patients undergoing PCI., Methods and Results: This multicenter, prospective, single-arm study was conducted in 5 countries (NCT03782688). Subjects underwent motorized fractional flow reserve pullbacks evaluation followed by optical coherence tomography-guided PCI. Post-PCI optical coherence tomography minimum stent area, stent expansion, and the presence of suboptimal findings such as incomplete stent apposition, stent edge dissection, and irregular tissue protrusion were compared between patients with focal versus diffuse disease. Overall, 102 patients (105 vessels) were included. Fractional flow reserve before PCI was 0.65±0.14, pullback pressure gradient was 0.66±0.14, and post-PCI fractional flow reserve was 0.88±0.06. The mean minimum stent area was 5.69±1.99 mm 2 and was significantly larger in vessels with focal disease (6.18±2.12 mm 2 versus 5.19±1.72 mm 2 , P =0.01). After PCI, incomplete stent apposition, stent edge dissection, and irregular tissue protrusion were observed in 27.6%, 10.5%, and 51.4% of the cases, respectively. Vessels with focal disease at baseline had a lower prevalence of incomplete stent apposition (11.3% versus 44.2%, P =0.002) and more irregular tissue protrusion (69.8% versus 32.7%, P <0.001)., Conclusions: Baseline coronary pathophysiological patterns are associated with suboptimal imaging findings after PCI. Patients with focal disease had larger minimum stent area and a higher incidence of tissue protrusion, whereas stent malapposition was more frequent in patients with diffuse disease.

The present study establishes a link between blood flow energy transformations in coronary atherosclerotic lesions and clinical outcomes. The predictive capacity for future myocardial infarction (MI) was compared with that of established quantitative coronary angiography (QCA)-derived predictors. Angiography-based computational fluid dynamics (CFD) simulations were performed on 80 human coronary lesions culprit of MI within 5 years and 108 non-culprit lesions for future MI. Blood flow energy transformations were assessed in the converging flow segment of the lesion as ratios of kinetic and rotational energy values (KER and RER, respectively) at the QCA-identified minimum lumen area and proximal lesion sections. The anatomical and functional lesion severity were evaluated with QCA to derive percentage area stenosis (%AS), vessel fractional flow reserve (vFFR), and translesional vFFR (ΔvFFR). Wall shear stress profiles were investigated in terms of topological shear variation index (TSVI). KER and RER predicted MI at 5 years (AUC = 0.73, 95% CI 0.65-0.80, and AUC = 0.76, 95% CI 0.70-0.83, respectively; p < 0.0001 for both). The predictive capacity for future MI of KER and RER was significantly stronger than vFFR (p = 0.0391 and p = 0.0045, respectively). RER predictive capacity was significantly stronger than %AS and ΔvFFR (p = 0.0041 and p = 0.0059, respectively). The predictive capacity for future MI of KER and RER did not differ significantly from TSVI. Blood flow kinetic and rotational energy transformations were significant predictors for MI at 5 years (p < 0.0001). The findings of this study support the hypothesis of a biomechanical contribution to the process of plaque destabilization/rupture leading to MI., (© 2023. The Author(s).)

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.)

Introduction: Diffuse disease has been identified as one of the main reasons leading to low post-PCI fractional flow reserve (FFR) and residual angina after PCI. Coronary pressure pullbacks allow for the evaluation of hemodynamic coronary artery disease (CAD) patterns. The pullback pressure gradient (PPG) is a novel metric that quantifies the distribution and magnitude of pressure losses along the coronary artery in a focal-to-diffuse continuum., Aim: The primary objective is to determine the predictive capacity of the PPG for post-PCI FFR., Methods: This prospective, large-scale, controlled, investigator-initiated, multicenter study is enrolling patients with at least 1 lesion in a major epicardial vessel with a distal FFR ≤ 0.80 intended to be treated by PCI. The study will include 982 subjects. A standardized physiological assessment will be performed pre-PCI, including the online calculation of PPG from FFR pullbacks performed manually. PPG quantifies the CAD pattern by combining several parameters from the FFR pullback curve. Post-PCI physiology will be recorded using a standardized protocol with FFR pullbacks. We hypothesize that PPG will predict optimal PCI results (post-PCI FFR ≥ 0.88) with an area under the ROC curve (AUC) ≥ 0.80. Secondary objectives include patient-reported and clinical outcomes in patients with focal vs. diffuse CAD defined by the PPG. Clinical follow-up will be collected for up to 36 months, and an independent clinical event committee will adjudicate events., Results: Recruitment is ongoing and is expected to be completed in the second half of 2023., Conclusion: This international, large-scale, prospective study with pre-specified powered hypotheses will determine the ability of the preprocedural PPG index to predict optimal revascularization assessed by post-PCI FFR. In addition, it will evaluate the impact of PPG on treatment decisions and the predictive performance of PPG for angina relief and clinical outcomes., Competing Interests: Disclosures AML reports receiving consultancy fees from Abbott and honoraria for sponsored symposiums from Abbott, Medtronic and Abiomed. DM report a research grant provided by the Cardiopath PhD program and speaker fees from Abbott Vascular. BDB reports receiving consultancy fees from Boston Scientific and Abbott and research grants from Coroventis Research, Pie Medical Imaging, Cathworks, Boston Scientific, Siemens, HeartFlow Inc. and Abbott Vascular. 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. BK has received consulting fees from Canon Medical, Abbott and Medtronic. AI has received consulting fees from Canon, Artrya Medical and Boston Scientific. TWJ has received consultancy/speaker fees from Abbott Vascular, Boston Scientific, Medtronic, Shockwave, Terumo and research grants from Abbott Vascular. NPJ 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 Corporation (DEFINE-FLOW, NCT02328820) for other studies using intracoronary pressure and flow sensors; has an institutional licensing agreement with Boston Scientific for the smart-minimum FFR algorithm (now commercialized under 510(k) K191008); and has patents pending on diagnostic methods for quantifying aortic stenosis and TAVI physiology, and on methods to correct pressure tracings from fluid-filled catheters. SB received research grants provided by Sahajanand Medical Technologies Ltd (SMT), Medis Medical Imaging Systems, Eukon S.r.l., Siemens Healthineers, General Electric (GE) Healthcare, and Insight Lifetech. EHC has received consulting fees from Abbott Medical Denmark A/S. CB receives research funding from the British Heart Foundation (RE/18/6134217, BHF/FS/17/26/32744, PG/19/28/34310). Colin Berry is employed by the University of Glasgow which holds consultancy and research agreements for his work with Abbott Vascular, AstraZeneca, Boehringer Ingelheim, Coroventis, GSK, HeartFlow, Menarini, Novartis, Servier, Siemens Healthcare, and Valo Health. WFF receives institutional research support from Abbot, Boston, and Medtronic and has consulting relationships with CathWorks and Siemens and stock options with HeartFlow. TE reports speakers and advisory board fees from Abbott, Boston and Novo Nordisk. AY has received minor honoraria from Abbott Vascular, and research grants from Abbott Vascular and Philips. DC has received consulting fees from Abbott. TS reports a grant provided by the EAPCI Fellowship Programme., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background Chronic kidney disease (CKD) might influence fractional flow reserve (FFR) value, potentially attenuating its prognostic utility. However, few large-scale data are available regarding clinical outcomes after FFR-guided deferral of revascularization in patients with CKD. Methods and Results From the J-CONFIRM registry (Long-Term Outcomes of Japanese Patients With Deferral of Coronary Intervention Based on Fractional Flow Reserve in Multicenter Registry), 1218 patients were divided into 3 groups according to renal function: (1) non-CKD (estimated glomerular filtration rate ≥60 mL/min per 1.73 m 2 ), n=385; (2) CKD (estimated glomerular filtration rate 15-59 mL/min per 1.73 m 2 , n=763); and (3) end-stage renal disease (ESRD) (eGFR <15 mL/min per 1.73 m 2 , n=70). The primary study end point was the cumulative 5-year incidence of target vessel failure (TVF), defined as a composite of cardiac death, target vessel myocardial infarction, and clinical driven target vessel revascularization. Cumulative 5-year incidence of TVF was significantly higher in the ESRD group than in the CKD and non-CKD group, whereas it did not differ between the CKD and non-CKD groups (26.3% versus 11.9% versus 9.5%, P <0.001). Although the 5-year TVF risk increased as the FFR value decreased regardless of renal function, patients with ESRD had a remarkably higher risk of TVF at every FFR value than those with CKD and non-CKD. Conclusions At 5 years, patients with ESRD showed a higher incidence of TVF than patients with CKD and non-CKD, although with similar outcomes between patients with CKD and non-CKD. Patients with ESRD had an excess risk of 5-year TVF at every FFR value compared with those with CKD and non-CKD. Registration URL: https://www.umin.ac.jp; Unique identifier: UMIN000014473.

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: A bolus thermodilution-derived index of microcirculatory resistance (IMR) has emerged as the standard for assessing coronary microvascular dysfunction (CMD). Continuous thermodilution has recently been introduced as a tool to quantify absolute coronary flow and microvascular resistance directly. Microvascular resistance reserve (MRR) derived from continuous thermodilution has been proposed as a novel metric of microvascular function, which is independent of epicardial stenoses and myocardial mass., Aims: We aimed to assess the reproducibility of bolus and continuous thermodilution in assessing coronary microvascular function., Methods: Patients with angina and non-obstructive coronary artery disease (ANOCA) at angiography were prospectively enrolled. Bolus and continuous intracoronary thermodilution measurements were obtained in duplicate in the left anterior descending artery (LAD). Patients were randomly assigned in a 1:1 ratio to undergo either bolus thermodilution first or continuous thermodilution first., Results: A total of 102 patients were enrolled. The mean fractional flow reserve (FFR) was 0.86±0.06. Coronary flow reserve (CFR) calculated with continuous thermodilution (CFR cont ) was significantly lower than bolus thermodilution-derived CFR (CFR bolus ; 2.63±0.65 vs 3.29±1.17; p<0.001). CFR cont showed a higher reproducibility than CFR bolus (variability: 12.7±10.4% continuous vs 31.26±24.85% bolus; p<0.001). MRR showed a higher reproducibility than IMR (variability 12.4±10.1% continuous vs 24.2±19.3% bolus; p<0.001). No correlation was found between MRR and IMR (r=0.1, 95% confidence interval: -0.09 to 0.29; p=0.305)., Conclusions: In the assessment of coronary microvascular function, continuous thermodilution demonstrated significantly less variability on repeated measurements than bolus thermodilution.

Background: Fractional flow reserve (FFR) measured after percutaneous coronary intervention (PCI) carries prognostic information. Yet, myocardial mass subtended by a stenosis influences FFR. We hypothesized that a smaller coronary lumen volume and a large myocardial mass might be associated with lower post-PCI FFR., Aim: We sought to assess the relationship between vessel volume, myocardial mass, and post-PCI FFR., Methods: This was a subanalysis with an international prospective study of patients with significant lesions (FFR ≤ 0.80) undergoing PCI. Territory-specific myocardial mass was calculated from coronary computed tomography angiography (CCTA) using the Voronoi's algorithm. Vessel volume was extracted from quantitative CCTA analysis. Resting full-cycle ratio (RFR) and FFR were measured before and after PCI. We assessed the association between coronary lumen volume (V) and its related myocardial mass (M), and the percent of total myocardial mass (%M) with post-PCI FFR., Results: We studied 120 patients (123 vessels: 94 left anterior descending arteries, 13 left Circumflex arteries, 16 right coronary arteries). Mean vessel-specific mass was 61 ± 23.1 g (%M 39.6 ± 11.7%). The mean post-PCI FFR was 0.88 ± 0.06 FFR units. Post-PCI FFR values were lower in vessels subtending higher mass (0.87 ± 0.05 vs. 0.89 ± 0.07, p = 0.047), and with lower V/M ratio (0.87 ± 0.06 vs. 0.89 ± 0.07, p = 0.02). V/M ratio correlated significantly with post-PCI RFR and FFR (RFR r = 0.37, 95% CI: 0.21-0.52, p < 0.001 and FFR r = 0.41, 95% CI: 0.26-0.55, p < 0.001)., Conclusion: Post-PCI RFR and FFR are associated with the subtended myocardial mass and the coronary volume to mass ratio. Vessels with higher mass and lower V/M ratio have lower post-PCI RFR and FFR., (© 2023 Wiley Periodicals LLC.)

Background: Angiographic fractional flow reserve (angioFFR) is a novel artificial intelligence (AI)-based angiography-derived fractional flow reserve (FFR) application. We investigated the diagnostic accuracy of angioFFR to detect hemodynamically relevant coronary artery disease., Methods and results: Consecutive patients with 30-90% angiographic stenoses and invasive FFR measurements were included in this prospective, single-center study conducted between November 2018 and February 2020. Diagnostic accuracy was assessed using invasive FFR as the reference standard. In patients undergoing percutaneous coronary intervention, gradients of invasive FFR and angioFFR in the pre-senting segments were compared. We assessed 253 vessels (200 patients). The accuracy of angioFFR was 87.7% (95% confidence interval [CI] 83.1-91.5%), with a sensitivity of 76.8% (95% CI 67.1-84.9%), specificity of 94.3% (95% CI 89.5-97.4%), and area under the curve of 0.90 (95% CI 0.86-0.93%). AngioFFR was well correlated with invasive FFR (r=0.76; 95% CI 0.71-0.81; P<0.001). The agreement was 0.003 (limits of agreement: -0.13, 0.14). The FFR gradients of angioFFR and invasive FFR were comparable (n=51; mean [±SD] 0.22±0.10 vs. 0.22±0.11, respectively; P=0.87)., Conclusions: AI-based angioFFR showed good diagnostic accuracy for detecting hemodynamically relevant stenosis using invasive FFR as the reference standard. The gradients of invasive FFR and angioFFR in the pre-stenting segments were comparable.

Background: Twenty percent to 40% of patients are affected by angina after percutaneous coronary intervention (PCI), which is associated with anxiety, depression, impaired physical function, and reduced quality of life. Understanding patient and procedural factors associated with post-PCI angina may inform alternative approaches to treatment., Methods: Two hundred thirty patients undergoing PCI completed the Seattle Angina Questionnaire (SAQ-7) and European quality of life-5 dimension-5 level (EQ-5D-5L) questionnaires at baseline and 3 months post-PCI. Patients received blinded intracoronary physiology assessments before and after stenting. A post hoc analysis was performed to compare clinical and procedural characteristics among patients with and without post-PCI angina (defined by follow-up SAQ-angina frequency score <100)., Results: Eighty-eight of 230 patients (38.3%) reported angina 3 months post-PCI and had a higher incidence of active smoking, atrial fibrillation, and history of previous myocardial infarction or PCI. Compared with patients with no angina at follow-up, they had lower baseline SAQ summary scores (69.48±24.12 versus 50.20±22.59, P <0.001) and EQ-5D-5L health index scores (0.84±0.15 versus 0.69±0.22, P <0.001). Pre-PCI fractional flow reserve (FFR) was lower among patients who had no post-PCI angina (0.56±0.15 versus 0.62±0.13, P =0.003). Percentage change in FFR after PCI had a moderate correlation with angina frequency score at follow-up ( r =0.36, P <0.0001). Patients with post-PCI angina had less improvement in FFR (43.1±33.5% versus 67.0±50.7%, P <0.001). There were no between-group differences in post-PCI FFR, coronary flow reserve, or corrected index of microcirculatory resistance. Patients with post-PCI angina had lower SAQ-summary scores (64.01±22 versus 95.16±8.72, P ≤0.001) and EQ-5D-5L index scores (0.69±0.26 versus 0.91±0.17, P ≤0.001) at follow-up., Conclusions: Larger improvements in FFR following PCI were associated with less angina and better quality of life at follow-up. In patients with stable symptoms, intracoronary physiology assessment can inform expectations of angina relief and quality of life improvement after stenting and thereby help to determine the appropriateness of PCI., Registration: URL: https://www., Clinicaltrials: gov; Unique identifier: NCT03259815.

Background: Cardiac stress tests remain the cornerstone for evaluating patients suspected of having obstructive coronary artery disease (CAD). Coronary microvascular dysfunction (CMD) can lead to abnormal non-invasive tests., Aims: We sought to assess the diagnostic performance of exercise stress tests with indexes of epicardial and microvascular resistance as reference., Methods: This was a prospective, single-arm, multicentre study of patients with an intermediate pretest probability of CAD and positive exercise stress tests who were referred for invasive angiography. Patients underwent an invasive diagnostic procedure (IDP) with measurement of fractional flow reserve (FFR) and index of microvascular resistance (IMR) in at least one coronary vessel. Obstructive CAD was defined as diameter stenosis (DS) >50% by quantitative coronary angiography (QCA). The objective was to determine the false discovery rate (FDR) of cardiac exercise stress tests with both FFR and IMR as references., Results: One hundred and seven patients (137 vessels) were studied. The mean age was 62.1±8.7, and 27.1% were female. The mean diameter stenosis was 37.2±27.5%, FFR was 0.84±0.10, coronary flow reserve was 2.74±2.07, and IMR 20.3±11.9. Obstructive CAD was present in 39.3%, whereas CMD was detected in 20.6%. The FDR was 60.7% and 62.6% with QCA and FFR as references (p-value=0.803). The combination of FFR and IMR as clinical reference reduced the FDR by 25% compared to QCA (45.8% vs 60.7%; p-value=0.006)., Conclusions: In patients with evidence of ischaemia, an invasive functional assessment accounting for the epicardial and microvascular compartments led to an improvement in the diagnostic performance of exercise tests, driven by a significant FDR reduction.

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 Coronary artery disease (CAD) patterns play an essential role in the decision-making process about revascularization. The pullback pressure gradient (PPG) quantifies CAD patterns as either focal or diffuse based on fractional flow reserve (FFR) pullbacks. The objective of this study was to evaluate the impact of CAD patterns on acute percutaneous coronary intervention (PCI) results considered surrogates of clinical outcomes. Methods and Results This was a prospective, multicenter study of patients with hemodynamically significant CAD undergoing PCI. Motorized FFR pullbacks and optical coherence tomography (OCT) were performed before and after PCI. Post-PCI FFR >0.90 was considered an optimal result. Focal disease was defined as PPG >0.73 (highest PPG tertile). Overall, 113 patients (116 vessels) were included. Patients with focal disease were younger than those with diffuse CAD (61.4±9.9 versus 65.1±8.7 years, P =0.042). PCI in vessels with high PPG (focal CAD) resulted in higher post-PCI FFR (0.91±0.07 in the focal group versus 0.86±0.05 in the diffuse group, P <0.001) and larger minimal stent area (6.3±2.3 mm 2 in focal versus 5.3±1.8 mm 2 in diffuse CAD, P =0.015) compared withvessels with low PPG (diffuse CAD). The PPG was associated with the change in FFR after PCI ( R 2 =0.51, P <0.001). The PPG significantly improved the capacity to predict optimal PCI results compared with an angiographic assessment of CAD patterns (area under the curve PPG 0.81 [95% CI, 0.73-0.88] versus area under the curve angio 0.51 [95% CI, 0.42-0.60]; P <0.001). Conclusions PCI in vessels with focal disease defined by the PPG resulted in greater improvement in epicardial conductance and larger minimal stent area compared with diffuse disease. PPG, but not angiographically defined CAD patterns, distinguished patients attaining superior procedural outcomes. Registration URL: https://clinicaltrials.gov/ct2/show/NCT03782688.

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.)

Fractional flow reserve (FFR) pullbacks assess the location and magnitude of pressure drops along the coronary artery. The pullback pressure gradient (PPG) quantifies the FFR pullback curve and provides a numeric expression of focal versus diffuse coronary artery disease. This study aims (1) to validate the PPG using manual FFR pullbacks compared with motorized FFR pullbacks as a reference; and (2) to determine the intra- and interoperator reproducibility of the PPG derived from manual FFR pullbacks. Patients with stable coronary artery disease and an FFR ≤ 0.80 were included. All patients underwent FFR pullback evaluation either with a motorized device or manually, depending on the study cohort. The agreement of the PPG between repeated pullbacks was assessed using the Bland-Altman method. Overall, 116 FFR pullback maneuvers (96 manual and 20 motorized) were analyzed. There was excellent agreement between the PPG derived from manual and motorized pullbacks (mean difference -0.01 ± 0.07, 95% limits of agreement [LOA] -0.14 to 0.12). The intra- and interoperator reproducibility of PPG derived from manual pullbacks were excellent (mean difference <0.01, 95% LOA -0.11 to 0.12, and mean difference <0.01, 95% LOA -0.12 to 0.11, respectively). The duration of the pullback maneuver did not impact the reproducibility of the PPG (r = 0.12, 95% CI: -0.29 to 0.49, p = 0.567). Manual pullbacks allow for an accurate PPG calculation. The inter- and intraoperator reproducibility of PPG derived from manual pullbacks were excellent., (© 2022 Wiley Periodicals LLC.)

Objective: To investigate the impact of invasive functional guidance for coronary artery bypass graft surgery (CABG) on graft failure., Background: Data on the impact of fractional flow reserve (FFR) in guiding CABG are still limited., Methods: Systematic review and individual patient data meta-analysis were performed. Primary objective was the risk of graft failure, stratified by FFR. Risk estimates are reported as odds ratios (ORs) derived from the aggregated data using random-effects models. Individual patient data were analyzed using mixed effect model to assess relationship between FFR and graft failure. This meta-analysis is registered in PROSPERO (CRD42020180444)., Results: Four prospective studies comprising 503 patients referred for CABG, with 1471 coronaries, assessed by FFR were included. Graft status was available for 1039 conduits at median of 12.0 [IQR 6.6; 12.0] months. Risk of graft failure was higher in vessels with preserved FFR (OR 5.74, 95% CI 1.71-19.29). Every 0.10 FFR units decrease in the coronaries was associated with 56% risk reduction of graft failure (OR 0.44, 95% CI 0.34 to 0.59). FFR cut-off to predict graft failure was 0.79., Conclusion: Surgical grafting of coronaries with functionally nonsignificant stenoses was associated with higher risk of graft failure., (© 2021 The Authors. Catheterization and Cardiovascular Interventions published by Wiley Periodicals LLC.)

Objectives: To characterize hemodynamics of serial coronary stenoses using fractional flow reserve (FFR) pullbacks and the pullback pressure gradients (PPG) index., Background: The cross-talk between stenoses within the same coronary artery makes the prediction of the functional contribution of each lesion challenging., Methods and Results: One-hundred seventeen patients undergoing coronary angiography for stable angina were prospectively recruited. Serial lesions were defined as two or more narrowings with visual diameter stenosis >50% on conventional angiography. Motorized FFR pullback tracings were obtained at 1 mm/s. Pullbacks were visually adjudicated as presenting two, one, and no focal pressure drops. The pattern of disease (i.e., focal or diffuse) was quantified using the PPG index. Twenty-five vessels presented serial lesions (mean PPG 0.48 ± 0.17). Two, one or no focal pressure drops were observed in 40% (n = 10; PPG 0.59 ± 0.17), 52% (n = 13; PPG 0.44 ± 0.12) and 8% of cases (n = 2; PPG 0.27 ± 0.01; p-value = 0.01). Distal FFR was similar between vessels with two, one and no focal pressure drops in the pullback curve (p-value = 0.27). The PPG index independently predicted the presence of two focal pressure drops in the pullback curve (p = 0.04)., Conclusions: FFR pullbacks in serial coronary lesions exhibit three distinct functional patterns. High PPG was associated with pullback curves presenting two pressure drops. The PPG provides a quantitative assessment of the pattern of coronary artery disease in cases with serial lesions and might be useful to assess the appropriateness of percutaneous revascularization., (© 2021 Wiley Periodicals LLC.)

Background: Myocardial perfusion imaging (MPI) and fractional flow reserve (FFR) are established approaches to the assessment of myocardial ischemia. Recently, various FFR cutoff values were proposed, but the diagnostic accuracy of MPI in identifying positive FFR using various cutoff values is not well established., Methods and results: We retrospectively studied 273 patients who underwent stress MPI and FFR within a 3-month period. Results for FFR were obtained from 218 left anterior descending artery (LAD) lesions and 207 non-LAD lesions. Stress MPI and FFR demonstrated a good correlation in the detection of myocardial ischemia. However, the positive predictive value (PPV) of FFR for detecting MPI-positive lesions at the optimal FFR thresholds was insufficient (44% for LAD and 65% for non-LAD lesions). This was caused by a sharp drop in PPV at an FFR threshold of 0.7 or more. Notably, 41% of the lesions with normal MPI demonstrated FFRs <0.80. However, MPI-negative lesions had an extremely low lesion rate with FFR <0.65 (6%). Conversely, 78% and 41% of MPI-positive lesions had FFR <0.80 and <0.65, respectively., Conclusions: The data confirmed that decisions based on MPI are reasonable because MPI-negative patients have an extremely low rate of lesions with a FFR below the cutoff point for a hard event, and MPI-positive lesions include many lesions with FFR <0.65.

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. For clinical decision making, it was recently recommended that values of fractional flow reserve (FFR) derived from coronary CTA (FFR CT ) be measured 1-2 cm distal to the stenosis, given the potential for overestimation of ischemia when FFR CT values at far distal segments are used. Supporting data are, however, lacking. OBJECTIVE. The purpose of the present study was to evaluate the diagnostic performance of FFR CT values measured 1-2 cm distal to the stenosis and at more distal locations relative to invasive FFR values. METHODS. FFR CT and invasive FFR values for 365 vessels in 253 patients identified from the Assessing Diagnostic Value of Noninvasive FFR CT in Coronary Care (ADVANCE) registry were prospectively assessed. FFR CT values were measured 1-2 cm distal to the stenosis and at the pressure wire position and far distal segments. The diagnostic accuracy of FFR CT was assessed on the basis of the ROC AUC. The AUC of FFR CT was calculated using FFR CT as an explanatory variable and an invasive FFR of 0.80 or less as the dichotomous dependent variable. RESULTS. The AUC of FFR CT values measured 1-2 cm distal to the stenosis (0.85; 95% CI, 0.80-0.88) was higher ( p = .002) than that of FFR CT values measured at far distal segments (0.80; 95% CI, 0.76-0.84) and similar ( p = .16) to that of FFR CT values measured at the pressure wire position (0.86; 95% CI, 0.81-0.89). FFR CT values measured 1-2 cm distal to the stenosis and at far distal segments had sensitivity of 87% versus 92% ( p = .003), specificity of 73% versus 42% ( p < .001), PPV of 75% versus 59% ( p < .001), and NPV of 86% versus 85% ( p = .72), respectively. Subgroup analyses of lesions of the left anterior descending coronary artery, left circumflex coronary artery, and right coronary artery all showed improved specificity and PPV (all p < .005) for FFR CT values measured 1-2 cm distal to the stenosis compared with values measured at the pressure wire position. However, the AUC was higher for measurements obtained 1-2 cm distal to the stenosis versus those obtained at far distal segments, for left anterior descending coronary artery lesions ( p < .001) but not for left circumflex coronary artery lesions ( p = .27) or right coronary artery lesions ( p = .91). CONCLUSION. The diagnostic performance of FFR CT values measured 1-2 cm distal to the stenosis was higher than that of FFR CT values measured at far distal segments and was similar to that of FFR CT values measured at the pressure wire position in evaluating ischemic status, particularly for left anterior descending coronary artery lesions. CLINICAL IMPACT. The present study supports recent recommendations from experts to use FFR CT measured 1-2 cm distal to the stenosis, rather than measurements obtained at far distal segments, in clinical decision making.

Introduction: Fractional flow reserve (FFR) measured after percutaneous coronary intervention (PCI) has been identified as a surrogate marker for vessel related adverse events. FFR can be derived from standard coronary computed tomography angiography (CTA). Moreover, the FFR derived from coronary CTA (FFR CT ) Planner is a tool that simulates PCI providing modeled FFR CT values after stenosis opening., Aim: To validate the accuracy of the FFR CT Planner in predicting FFR after PCI with invasive FFR as a reference standard., Methods: Prospective, international and multicenter study of patients with chronic coronary syndromes undergoing PCI. Patients will undergo coronary CTA with FFR CT prior to PCI. Combined morphological and functional evaluations with motorized FFR hyperemic pullbacks, and optical coherence tomography (OCT) will be performed before and after PCI. The FFR CT Planner will be applied by an independent core laboratory blinded to invasive data, replicating the invasive procedure. The primary objective is to assess the agreement between the predicted FFR CT post-PCI derived from the Planner and invasive FFR. A total of 127 patients will be included in the study., Results: Patient enrollment started in February 2019. Until December 2020, 100 patients have been included. Mean age was 64.1 ± 9.03, 76% were males and 24% diabetics. The target vessels for PCI were LAD 83%, LCX 6%, and RCA 11%. The final results are expected in 2021., Conclusion: This study will determine the accuracy and precision of the FFR CT Planner to predict post-PCI FFR in patients with chronic coronary syndromes undergoing percutaneous revascularization., (© 2021 The Authors. Clinical Cardiology published by Wiley Periodicals LLC.)

Objectives: The aim of this study was to investigate the accuracy of pre-percutaneous coronary intervention (PCI) predicted nonhyperemic pressure ratios (NHPRs) with actual post-PCI NHPRs and to assess the efficacy of PCI strategy using pre-PCI NHPR pullback., Background: Predicting the functional results of PCI is feasible using pre-PCI longitudinal vessel interrogation with the instantaneous wave-free ratio (iFR), a pressure-based, adenosine-free NHPR. However, the reliability of novel NHPRs (resting full-cycle ratio [RFR] and diastolic pressure ratio [dPR]) for this purpose remains uncertain., Methods: In this prospective, multicenter, randomized controlled trial, vessels were randomly assigned to receive pre-PCI iFR, RFR, or dPR pullback (50 vessels each). The pre-PCI predicted NHPRs were compared with actual NHPRs after contemporary PCI using intravascular imaging. The number and the total length of treated lesions were compared between NHPR pullback-guided and angiography-guided strategies., Results: The predicted NHPRs were strongly correlated with actual NHPRs: iFR, r = 0.83 (95% confidence interval: 0.72 to 0.90; p < 0.001); RFR, r = 0.84 (95% confidence interval: 0.73 to 0.91; p < 0.001), and dPR, r = 0.84 (95% confidence interval: 0.73 to 0.91; p < 0.001). The number and the total length of treated lesions were lower with the NHPR pullback strategy than with the angiography-guided strategy, leading to physiological improvement., Conclusions: Predicting functional PCI results on the basis of pre-procedural RFR and dPR pullbacks yields similar results to iFR. Compared with an angiography-guided strategy, a pullback-guided PCI strategy with any of the 3 NHPRs reduced the number and the total length of treated lesions. (Study to Examine Correlation Between Predictive Value and Post PCI Value of iFR, RFR and dPR; UMIN000033534)., Competing Interests: Author Relationship With Industry Dr. Escaned has provided consulting and speaking services at educational events for Abbott, Boston Scientific, and Philips Healthcare. Dr. Mizukami has received consulting fees from HeartFlow. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2020. Published by Elsevier Inc.)

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.)

Objectives: The present study aimed at determining the accuracy and reproducibility of motorized FFR pullbacks in patients with stable coronary artery disease., Background: Fractional flow reserve (FFR) is recommended for decision making regarding myocardial revascularization. The distribution of epicardial resistance along coronary vessels can be assessed using FFR pullbacks., Methods: Duplicated FFR pullbacks were acquired using a motorized device at a speed of 1 mm/s in intermediate coronary stenosis. In addition, a single FFR value was measured at an anatomical landmark. The agreement between FFR measurements was assessed using the Bland-Altman method, Pearson's correlation coefficient and area under the pullback curve (AUPC)., Results: In 20 vessels, 37,326 FFR values were obtained. The mean FFR from the pullbacks was 0.91 ± 0.08 whereas the mean FFR at the distal location was 0.85 ± 0.09. The mean difference between pullbacks was -0.002 (LOA -0.058 to 0.054). The difference in AUPC between the two FFR pullbacks was 2.1 ± 1.6%. At pre-specified anatomical locations, the mean difference between the FFR derived from the pullback data and the measured FFR was 0 (LOA -0.040 to 0.039). The repeatability of the distal FFR measurement was high (bias -0.003, LOA -0.046 to 0.041)., Conclusion: A motorized FFR pullback was accurate to assess the distribution of epicardial resistance in patients with intermediate coronary artery disease. The reproducibility of the FFR pullback was high. Further studies are required to determine the potential usefulness of a hyperemic FFR pullback strategy for decision making and treatment planning., (© 2020 Wiley Periodicals, Inc.)

Background: Cardiac allograft vasculopathy (CAV) remains the Achilles' heel of long-term survival after heart transplantation (HTx). The severity and extent of CAV is graded with conventional coronary angiography (COR) which has several limitations. Recently, vessel fractional flow reserve (vFFR) derived from COR has emerged as a diagnostic computational tool to quantify the functional severity of coronary artery disease., Purpose: The present study assessed the usefulness of vFFR to detect CAV in HTx recipients., Methods: In HTx patients referred for annual check-up, undergoing surveillance COR, the extent of CAV was graded according to the criteria proposed by the international society of heart and lung transplantation (ISHLT). In addition, three-dimensional coronary geometries were constructed from COR to calculate pressure losses using vFFR., Results: In 65 HTx patients with a mean age of 53.7 ± 10.1 years, 8.5 years (IQR 1.90, 15.2) years after HTx, a total number of 173 vessels (59 LAD, 61 LCX, and 53 RCA) were analyzed. The mean vFFR was 0.84 ± 0.15 and median was 0.88 (IQR 0.79, 0.94). A vFFR ≤ 0.80 was present in 24 patients (48 vessels). HTx patients with a history of ischemic cardiomyopathy (ICMP) had numerically lower vFFR as compared to those with non-ICMP (0.70 ± 0.22 vs. 0.79 ± 0.13, p = 0.06). The use of vFFR reclassified 31.9% of patients compared to the anatomical ISHLT criteria. Despite a CAV score of 0, a pathological vFFR ≤ 0.80 was detected in 8 patients (34.8%)., Conclusion: The impairment in epicardial conductance assessed by vFFR in a subgroup of patients without CAV according to standard ISHLT criteria suggests the presence of a diffuse vasculopathy undetectable by conventional angiography. Therefore, we speculate that vFFR may be useful in risk stratification after HTx., Competing Interests: The authors declare that there are no conflicts of interest regarding the publication of this paper., (Copyright © 2020 Sakura Nagumo et al.)

Aims: Fractional flow reserve (FFR) pullback allows to assess the distribution of pressure loss along the coronary vessels. FFR derived from CT (FFR CT ) provides a virtual pullback curve that may also aid in the assessment of the distribution of epicardial coronary resistance in the non-invasive setting. The present study aims to determine the accuracy of the virtual FFR CT pullback curve using a motorized invasive FFR pullback as reference in patients with stable coronary artery disease., Methods and Results: FFR values were extracted from coronary vessels at approximately 1 mm to generate pullback curves. Invasive motorized FFR pullbacks were acquired using a dedicated device at a speed of 1 mm/s. A total of 3172 matched FFR CT and FFR values were obtained in 24 vessels. The correlation coefficient between FFR CT and FFR was 0.76 (95%CI 0.75 to 0.78; p < 0.001). The area under the pullback curve was similar between FFR CT and invasive FFR (79.0 ± 16.1 vs. 85.3 ± 16.4, p = 0.097). The mean difference in lesion gradient between FFR CT and FFR was -0.07 (LOA -0.26 to 0.13) whereas in non-obstructive segments was -0.01 (LOA -0.06 to 0.05)., Conclusion: The evaluation of epicardial coronary resistance using coronary CT angiography with FFR CT was feasible. FFR CT virtual pullback appears to be accurate for the evaluation of pressure gradients. FFR CT has the potential to identify the pathophysiological pattern of coronary artery disease in the non-invasive setting., Competing Interests: Declaration of competing interest TM has been supported by a research grant provided by HeartFlow Inc. JS reports receiving research grant from the Cardiopath PhD. program. CC has been supported by a research grant provided by HeartFlow Inc and Biosensors. BDB declares that the Cardiovascular Center Aalst receives on his behalf grant support from Abbott, Boston Scientific, Biotronik, and St. Jude Medical and consulting fees from St. Jude Medical, Opsens, and Boston Scientific. He is a shareholder for Siemens, GE, Bayer, Philips, Heartflow Inc, Edwards LifeSciences, Sanofi, and Omega Pharma. DA received research grant from GE Healthcare and Bracco. The other authors have nothing to disclose., (Copyright © 2020 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.)

Coronary computed tomography angiography (CCTA) is at the frontline of the diagnostic strategies to detect coronary artery disease (CAD). Anatomical information have proven to be insufficient to detect hemodynamic significant epicardial stenosis. In the present invited review we discuss on FFR CT and stress CTP, emerging technologies for an accurate and comprehensive evaluation of patients with suspected CAD, offering both anatomical (i.e. luminal and plaque) and functional assessment in one single technique., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Background: Diffuse atherosclerosis is commonly observed in angiographically normal segments in patients with stable coronary artery disease (CAD). The distribution of epicardial resistance along the vessel can be evaluated using coronary physiology., Objectives: The purpose of this study was to characterize the pathophysiological patterns of CAD using invasive pressure pullbacks during continuous hyperemia., Methods: In this prospective, multicenter study of patients undergoing clinically-indicated coronary angiography due to stable angina, a pressure-wire pullback device was set at a speed of 1 mm/s. Based on coronary angiography and on the fractional flow reserve (FFR) pullback curve, the patterns of CAD were adjudicated as focal, diffuse, or a combination of both. The distribution of epicardial resistance was characterized using the hyperemic pullback pressure gradients (PPGs). The PPG index, a continuous metric based on the magnitude of pressure drop over 20 mm and on the extent of functional disease was computed to determine the pattern of CAD. Low PPG index indicates diffuse CAD., Results: A total of 158 vessels (n = 117) were included. Overall, 984,813 FFR values were used to generate 100 FFR pullback curves. Using coronary physiology, 36% of the vessel disease patterns were reclassified compared to angiography. The median of maximal PPG over 20 mm was 0.083 (interquartile range: 0.063 to 0.118) FFR units, and the mean extent of functional disease was 39.3 ± 21.3 mm. The mean PPG index was 0.58 ± 0.18 and differentiated pathophysiological focal and diffuse disease (p < 0.001)., Conclusions: Pathophysiological patterns of CAD can be characterized by motorized hyperemic PPGs. The evaluation of the FFR pullback curve reclassified one-third of the vessels' disease patterns compared with conventional angiography. The PPG index is a novel metric that quantifies the distribution of epicardial resistance and discriminates focal from diffuse CAD. (Physiological Patterns of Coronary Artery Disease; NCT03824600)., (Copyright © 2019 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)