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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/purpose: It is unclear whether coronary physiology or coronary angiography (CA)-guided strategy is the more preferable approach for deferring percutaneous coronary intervention (PCI). We sought to evaluate the clinical efficacy of various PCI strategies through a network meta-analysis of randomized controlled trials (RCTs)., Methods/materials: We searched multiple databases for RCTs investigating the impact of the following strategies for the purpose of determining whether or not to defer PCI: fractional flow reserve, instantaneous wave-free ratio, quantitative flow ratio (QFR), and CA. We conducted a network meta-analysis for trial-defined major adverse cardiovascular events (MACE), all-cause death, cardiovascular death, myocardial infarction (MI), target lesion revascularization (TLR), and stent thrombosis. We performed a subgroup analysis for those with acute coronary syndrome (ACS)., Results: Our search identified 12 eligible RCTs including a total of 13,177 patients. QFR-guided PCI was associated with reduced MACE, MI, and TLR compared with CA-guided PCI (relative risk (RR) 0.68; 95 % confidence interval (CI] [0.49 to 0.94], RR 0.58; 95 % CI [0.36 to 0.96], and RR 0.58; 95 % CI [0.38 to 0.91], respectively). There were no significant differences in any pairs for all-cause death, cardiovascular death, or stent thrombosis. QFR was ranked the best in most outcomes. In the subgroup analysis of the ACS cohort, there were no significant differences in MACE between any comparisons., Conclusions: QFR was associated with reduced MACE, MI, and TLR compared with CA, and ranked the best in most outcomes. However, this was not applied in the ACS cohort., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: Nonhyperemic pressure ratios (NHPRs) have been proposed as alternatives to fractional flow reserve (FFR) without induction of hyperemia. More recently, imaging based-FFR estimation, especially coronary angiography-derived FFR (Angio-FFR) measurement, is proposed to estimate wire-based FFR. However, little is known about the diagnostic performance of these indices against conventional FFR., Aims: We aimed to assess and compare the diagnostic performance of both NHPRs and coronary Angio-FFR against wire-based conventional FFR., Methods: PubMed and Embase databases were systematically searched for peer-reviewed original articles up to 08/2022. The primary outcomes were the pooled sensitivity and specificity as well as the area under the curve (AUC) of the summary receiver-operating characteristic curve of those indices., Results: A total of 6693 records were identified after a literature search, including 37 reports for NHPRs and 34 for Angio-FFR. Overall, NHPRs have a lower diagnostic performance in estimating wire-based FFR with an AUC of 0.85 (0.81, 0.88) when compared with Angio-FFR of 0.95 (0.93, 0.97). When all four modalities of NHPRs (iFR, Pd/Pa, DPR, RFR) were compared, those had overlapping AUCs without major differences among each other. Similarly, when the two most commonly used Angio-FFR (QFR, FFR angio ) were compared, those had overlapping AUCs without major differences among each other., Conclusion: Angio-FFR may offer a better estimation of wire-based FFR than NHPRs. Our results support a wider use of Angio-FFR in the cardiac catheterization laboratory to streamline our workflow for coronary physiologic assessment., Classifications: FFR,, stable ischemic disease and non-ST elevation acute coronary syndrome., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Fractional flow reserve (FFR) has become the gold standard for invasively assessing the functional significance of coronary artery disease (CAD) to guide revascularization. The amount of evidence supporting the role of FFR in the cardiac catheterization laboratory is large and still growing. However, FFR uptake in the daily practice is limited by a variety of factors such as invasive instrumentation of the coronary artery that requires extra time and need for vasodilator medications for hyperemia. In this review, we describe the details of wire-based alternatives to FFR, providing insights as to their development, clinical evidence, and limitations., Competing Interests: Disclosure M.A. Parikh serves on the advisory boards of Abbott Vascular, Boston Scientific, and Medtronic. Y. Kobayashi serves as a consultant for Abbott Vascular. Others have no conflict of interest to disclose., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: Previous studies comparing percutaneous coronary intervention (PCI) with coronary artery bypass grafting (CABG) in patients with multivessel coronary disease not involving the left main have shown significantly lower rates of death, myocardial infarction (MI), or stroke after CABG. These studies did not routinely use current-generation drug-eluting stents or fractional flow reserve (FFR) to guide PCI., Methods: FAME 3 (Fractional Flow Reserve versus Angiography for Multivessel Evaluation) is an investigator-initiated, multicenter, international, randomized trial involving patients with 3-vessel coronary artery disease (not involving the left main coronary artery) in 48 centers worldwide. Patients were randomly assigned to receive FFR-guided PCI using zotarolimus drug-eluting stents or CABG. The prespecified key secondary end point of the trial reported here is the 3-year incidence of the composite of death, MI, or stroke., Results: A total of 1500 patients were randomized to FFR-guided PCI or CABG. Follow-up was achieved in >96% of patients in both groups. There was no difference in the incidence of the composite of death, MI, or stroke after FFR-guided PCI compared with CABG (12.0% versus 9.2%; hazard ratio [HR], 1.3 [95% CI, 0.98-1.83]; P =0.07). The rates of death (4.1% versus 3.9%; HR, 1.0 [95% CI, 0.6-1.7]; P =0.88) and stroke (1.6% versus 2.0%; HR, 0.8 [95% CI, 0.4-1.7]; P =0.56) were not different. MI occurred more frequently after PCI (7.0% versus 4.2%; HR, 1.7 [95% CI, 1.1-2.7]; P =0.02)., Conclusions: At 3-year follow-up, there was no difference in the incidence of the composite of death, MI, or stroke after FFR-guided PCI with current-generation drug-eluting stents compared with CABG. There was a higher incidence of MI after PCI compared with CABG, with no difference in death or stroke. These results provide contemporary data to allow improved shared decision-making between physicians and patients with 3-vessel coronary artery disease., Registration: URL: https://www., Clinicaltrials: gov; Unique identifier: NCT02100722., Competing Interests: Disclosures Dr Pijls receives 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 Mansour has consulting relationships with Abbott Vascular, Amgen, AstraZeneca, Bayer, Boehringer Ingelheim, Novartis, Pfizer, and Servier Affaires, and received a research grant from Opsens Inc and Abbott Vascular. Dr Kala has a consulting relationship with Boston Scientific, Medtronic, and Servier Affaires, and receives honoraria from AstraZeneca and Bayer. Dr Angeras receives research funding from Abbott Vascular and AstraZeneca and has a consulting relationship with Abbott Vascular and Boston Scientific. Dr Miner has a consulting relationship with Abbott, Amgen, Astra Zeneca, Bayer, Boehringer, Novartis, Opsens, Pfizer, and Servier Affaires Medicales. Dr Engstrøm has a consulting relationship with Abbott Vascular, Bayer, and Novo Nordisk. Dr Christiansen has a consulting relationship with Abbott Vascular and has received research grants from Abbott Vascular. Dr Tonino has received research grants from Biosensors and Opsens. Dr Reardon has a consulting relationship with Boston Scientific and W.L. Gore & Associates. Dr Otsuki has received research grants from the Uehara Memorial Foundation, Abbott, Medtronic, Boston Scientific, and Terumo. Dr Kobayashi has a consulting relationship with Abbott Vascular. Dr Hlatky has a consulting relationship with Blue Cross and Blue Shield and research support from HeartFlow. Dr Mahaffey has received research grants or contracts from the American Heart Association, Apple, Inc, Bayer, California Institute Regenerative Medicine, Eidos, Ferring, Gilead, Google (Verily), Idorsia, Johnson & Johnson, Luitpold, PAC-12, Precordior, and Sanifit; has provided consulting or other services for Amgen, Applied Therapeutics, AstraZeneca, Bayer, CSL Behring, Elsevier, FibroGen, Inova, Johnson & Johnson, Lexicon, MyoKardia, Novartis, Novo Nordisk, Otsuka, PhaseBio, Portola, Quidel, Sanofi, and Theravance; and has equity in Precordior. Dr Yeung has a consulting relationship with Medtronic. Dr De Bruyne has an institutional consulting relationship with Boston Scientific, Abbott Vascular, CathWorks, Siemens, GE Healthcare, and Coroventis Research; receives institutional research grants from Abbott Vascular, Coroventis Research, CathWorks, and Boston Scientific; and holds minor equities in Philips, Siemens, GE Healthcare, CathWorks, Edwards Life Sciences, HeartFlow, Opsens, Celyad, Xenter, Medyria, Bayer, and Sanofi. Dr Fearon receives research funding from Abbott, Medtronic, and Boston Scientific and has a consulting relationship with Siemens and CathWorks and stock options with HeartFlow. The other authors report no conflicts of interest.

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.)

Fractional flow reserve (FFR) has become the gold standard for invasively assessing the functional significance of coronary artery disease (CAD) to guide revascularization. The amount of evidence supporting the role of FFR in the cardiac catheterization laboratory is large and still growing. However, FFR uptake in the daily practice is limited by a variety of factors such as invasive instrumentation of the coronary artery that requires extra time and need for vasodilator medications for hyperemia. In this review, we describe the details of wire-based alternatives to FFR, providing insights as to their development, clinical evidence, and limitations., Competing Interests: Disclosure M.A. Parikh serves on the advisory boards of Abbott Vascular, Boston Scientific, and Medtronic. Y. Kobayashi serves as a consultant for Abbott Vascular. Others have no conflict of interest to disclose., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background: Little is known about the overall diagnostic performance of computational fractional flow reserve (FFR) derived from angiography (Angio-FFR), intravascular ultrasound (IVUS-FFR), and optical coherence tomography (OCT-FFR) to detect hemodynamically significant coronary artery disease. The present study aimed to evaluate the diagnostic performance of those novel physiologic indices using conventional FFR as the gold standard., Methods: PubMed and Embase were searched in September 2021 for a systematic review and meta-analysis of studies assessing the diagnostic performance of invasive imaging-derived FFR. The primary outcomes were the summary sensitivity, specificity, correlation coefficients of each index., Results: A total of 6572 records were initially identified and 49 studies were included in the final analysis (7010 lesions from 36 studies for Angio-FFR, 305 lesions from 5 studies for IVUS-FFR, and 667 lesions from 8 studies for OCT-FFR). Invasive imaging-derived FFR had a high diagnostic performance to detect functionally significant coronary lesions using conventional FFR as the gold standard [Angio-FFR, sensitivity 0.87 (95% CI 0.84-0.89), specificity 0.93 (95% CI 0.910.95); IVUS-FFR, sensitivity 0.90 (95% CI 0.84-0.94), specificity 0.95 (95% CI 0.90-0.98); OCT-FFR, sensitivity 0.85 (95% CI 0.78-0.91), specificity 0.93 (95% CI 0.89-0.95)]. The summary correlation coefficients of Angio-, IVUS-, and OCT-FFRs with wire-based FFR were 0.83 (95% CI 0.80-0.85), 0.85 (95% CI 0.79-0.91), and 0.80 (95% CI 0.74-0.86), respectively., Conclusions: This meta-analysis demonstrated that computational FFR derived from invasive coronary imaging has clinically acceptable diagnostic performances irrespective of modalities, supporting their applicability to clinical practice., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Background: Patients with three-vessel coronary artery disease have been found to have better outcomes with coronary-artery bypass grafting (CABG) than with percutaneous coronary intervention (PCI), but studies in which PCI is guided by measurement of fractional flow reserve (FFR) have been lacking., Methods: In this multicenter, international, noninferiority trial, patients with three-vessel coronary artery disease were randomly assigned to undergo CABG or FFR-guided PCI with current-generation zotarolimus-eluting stents. The primary end point was the occurrence within 1 year of a major adverse cardiac or cerebrovascular event, defined as death from any cause, myocardial infarction, stroke, or repeat revascularization. Noninferiority of FFR-guided PCI to CABG was prespecified as an upper boundary of less than 1.65 for the 95% confidence interval of the hazard ratio. Secondary end points included a composite of death, myocardial infarction, or stroke; safety was also assessed., Results: A total of 1500 patients underwent randomization at 48 centers. Patients assigned to undergo PCI received a mean (±SD) of 3.7±1.9 stents, and those assigned to undergo CABG received 3.4±1.0 distal anastomoses. The 1-year incidence of the composite primary end point was 10.6% among patients randomly assigned to undergo FFR-guided PCI and 6.9% among those assigned to undergo CABG (hazard ratio, 1.5; 95% confidence interval [CI], 1.1 to 2.2), findings that were not consistent with noninferiority of FFR-guided PCI (P = 0.35 for noninferiority). The incidence of death, myocardial infarction, or stroke was 7.3% in the FFR-guided PCI group and 5.2% in the CABG group (hazard ratio, 1.4; 95% CI, 0.9 to 2.1). The incidences of major bleeding, arrhythmia, and acute kidney injury were higher in the CABG group than in the FFR-guided PCI group., Conclusions: In patients with three-vessel coronary artery disease, FFR-guided PCI was not found to be noninferior to CABG with respect to the incidence of a composite of death, myocardial infarction, stroke, or repeat revascularization at 1 year. (Funded by Medtronic and Abbott Vascular; FAME 3 ClinicalTrials.gov number, NCT02100722.)., (Copyright © 2021 Massachusetts Medical Society.)

Despite the current evidence supporting clinical benefits of fractional flow reserve (FFR), its uptake in the cardiac catheterization laboratory has been slow due to procedural cost and increased time with the need for maximum hyperemia. Recently, novel physiological indices derived from coronary angiography and intracoronary imaging have emerged to overcome issues with a wire-based FFR. Angiography-based FFR can be measured without vessel instrumentation and has shown excellent diagnostic performance using wire-based FFR as the reference standard. Thus, angiography-based FFR may facilitate coronary functional assessment before and after percutaneous coronary intervention (PCI). Angiography-based index of microcirculatory resistance (IMR) is another new computational index for assessing the coronary microcirculation. Although angiography-derived IMR remains in an early phase of development and requires further validation, its less-invasive nature may help broaden the adoption of microvascular functional assessment in various conditions such as myocardial infarction and cardiac allograft vasculopathy. Lastly, computational FFR based on intravascular ultrasound and optical coherence tomography allows detailed lesion assessment from both morphological and functional standpoints. Given a growing interest in physiology-guided PCI optimization strategies, intravascular imaging-based FFR may become the main assessment tool to confirm successful PCI., Competing Interests: Declaration of Competing Interest A.L. has served on Advisory Boards for Medtronic, Boston Scientific, Philips, Canon, CorFlow, and Abbott. Y.K. has served as a consultant to Abbott Vascular Inc. and CONAVI Medical Inc. T.T., K.T., and H.O. have no financial conflict of interest to disclose., (Copyright © 2021. Published by Elsevier Ltd.)

Background: A large, prospective, multicentre trial recently showed that fractional flow reserve (FFR) derived from coronary angiography (FFRangio) has an accuracy of 92% compared with conventional guidewire-based FFR (FFRwire); however, little is known about whether specific patient/lesion characteristics affect the diagnostic performance., Aims: The primary goal of the present study was to investigate whether specific patient or lesion characteristics such as high body mass index (BMI), presentation with an acute coronary syndrome, or lesion location affect the diagnostic performance of FFRangio in patients enrolled in the FAST-FFR study., Methods: FFRangio was measured in a blinded fashion in 301 patients (319 vessels) who were undergoing FFRwire assessment. Using an FFRwire ≤0.80 as a reference, the diagnostic performance of FFRangio was compared in pre-specified subgroups., Results: The mean FFRwire and FFRangio were 0.81±0.13 and 0.80±0.12. Overall, FFRangio had a sensitivity of 93.5% and specificity of 91.2% for predicting FFRwire. Patient characteristics including age, sex, clinical presentation, body mass index, and diabetes did not affect sensitivity or specificity (p>0.05 for all). Similarly, lesion characteristics including calcification and tortuosity did not affect sensitivity or specificity (p>0.05 for all), nor did lesion location (proximal, middle, versus distal). Sensitivity was equally high across all target vessels, while specificity was highest in the LAD and lower (~85%) in the RCA and LCx (p<0.05)., Conclusions: FFRangio derived from coronary angiography has a high diagnostic performance regardless of patient and most lesion characteristics. The interaction of vessel on the specificity will need to be confirmed in larger cohorts.

Background: Whether the benefit in quality of life (QOL) after percutaneous coronary intervention depends on the severity of the stenosis as determined by fractional flow reserve (FFR) remains unknown. This study sought to investigate the relationship between FFR values and improvement in QOL., Methods: From the FAME 1 and 2 trials (Fractional Flow Reserve Versus Angiography for Multivessel Evaluation), we identified 706 stable patients with coronary artery disease who had at least 1 lesion with an FFR≤0.80 that was treated with percutaneous coronary intervention and 185 patients with coronary artery disease who had no lesion with an FFR≤0.80 and were treated medically who served as a reference group. QOL was assessed by the European Quality of Life-5 Dimensions index at baseline, 1 month, and 1 year. We assessed the relationship between QOL improvement (defined as the change in European Quality of Life-5 Dimensions index from baseline) and FFR as a continuous value and according to abnormal FFR tertile., Results: QOL improved significantly after percutaneous coronary intervention in each abnormal FFR tertile, whereas it did not change in the reference group. The lowest abnormal FFR subgroup had the greatest improvement in QOL at 1 month ( P<0.001). In mixed-effects models for repeated measures, lower FFR ( P=0.002 for 1 month and 0.049 for 1 year), greater delta FFR ( P=0.021 for 1 month and 0.025 for 1 year), and higher angina class ( P=0.001 for 1 month and <0.001 for 1 year) were associated with the greatest magnitude of QOL improvement at both 1 month and 1 year., Conclusions: Among patients with stable coronary artery disease, FFR and angina severity predict QOL improvement after percutaneous coronary intervention., Clinical Trial Registration: URL: https://www.clinicaltrials.gov . Unique identifiers: NCT00267774 and NCT01132495.

Objectives: The goal of this study was to investigate sex differences in adenosine-free coronary pressure indexes., Background: Several adenosine-free coronary pressure wire indexes have been proposed to assess the functional significance of coronary artery lesions; however, there is a theoretical concern that sex differences may affect diagnostic performance because of differences in resting flow and distal myocardial mass., Methods: In this CONTRAST (Can Contrast Injection Better Approximate FFR Compared to Pure Resting Physiology?) substudy, contrast fractional flow reserve (cFFR), obtained during contrast-induced submaximal hyperemia, the instantaneous wave-free ratio (iFR), and distal/proximal coronary pressure ratio (Pd/Pa) were compared with fractional flow reserve (FFR) in 547 men and 216 women. Using FFR ≤0.8 as a reference, the diagnostic performance of each index was compared., Results: Men and women had similar diameter stenosis (p = 0.78), but women were less likely to have FFR ≤0.80 than men (42.5% vs. 51.5%, p = 0.04). Sensitivity was similar among cFFR, iFR, and Pd/Pa when comparing women and men, respectively (cFFR, 77.5% vs. 75.3%; p = 0.69; iFR, 84.9% vs. 79.4%; p = 0.30; Pd/Pa, 78.8% vs. 77.3%; p = 0.78). cFFR was more specific than iFR or Pd/Pa regardless of sex (cFFR, 94.3% vs. 95.8%; p = 0.56; iFR, 75.6% vs. 80.1%; p = 0.38; Pd/Pa, 80.6% vs. 78.7%; p = 0.69). By receiver-operating characteristic curve analysis, cFFR provided better diagnostic accuracy than resting indexes irrespective of sex (p ≤ 0.0001)., Conclusions: Despite the theoretical concern, the diagnostic sensitivity and specificity of cFFR, iFR, and Pd/Pa did not differ between the sexes. Irrespective of sex, cFFR provides the best diagnostic performance., (Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Contrast fractional flow reserve (cFFR) is a method for assessing functional significance of coronary stenoses, which is more accurate than resting indices and does not require adenosine. However, contrast media volume and osmolality may affect the degree of hyperemia and therefore diagnostic performance., Methods and Results: cFFR, instantaneous wave-free ratio, distal pressure/aortic pressure at rest, and FFR were measured in 763 patients from 12 centers. We compared the diagnostic performance of cFFR between patients receiving low or iso-osmolality contrast (n=574 versus 189) and low or high contrast volume (n=341 versus 422) using FFR≤0.80 as a reference standard. The sensitivity, specificity, and overall accuracy of cFFR for the low versus iso-osmolality groups were 73%, 93%, and 85% versus 87%, 90%, and 89%, and for the low versus high contrast volume groups were 69%, 99%, and 83% versus 82%, 93%, and 88%. By receiver operating characteristics (ROC) analysis, cFFR provided better diagnostic performance than resting indices regardless of contrast osmolality and volume ( P <0.001 for all groups). There was no significant difference between the area under the curve of cFFR in the low- and iso-osmolality groups (0.938 versus 0.957; P =0.40) and in the low- and high-volume groups (0.939 versus 0.949; P =0.61). Multivariable logistic regression analysis showed that neither contrast osmolality nor volume affected the overall accuracy of cFFR; however, both affected the sensitivity and specificity., Conclusions: The overall accuracy of cFFR is greater than instantaneous wave-free ratio and distal pressure/aortic pressure and not significantly affected by contrast volume and osmolality. However, contrast volume and osmolality do affect the sensitivity and specificity of cFFR., Clinical Trial Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02184117., (© 2017 American Heart Association, Inc.)

Cardiac allograft vasculopathy is a major cause of long-term graft failure following heart transplantation. Asymmetric dimethylarginine (ADMA), a marker of endothelial dysfunction, has been mechanistically implicated in the development of cardiac allograft vasculopathy, but its impact on coronary physiology early after transplantation is unknown. Invasive indices of coronary physiology, namely, fractional flow reserve (FFR), the index of microcirculatory resistance, and coronary flow reserve, were measured with a coronary pressure wire in the left anterior descending artery within 8 weeks (baseline) and 1 year after transplant. Plasma levels of ADMA were concurrently assayed using high-performance liquid chromatography. In 46 heart transplant recipients, there was a statistically significant correlation between elevated ADMA levels and lower FFR values at baseline (r = -0.33; p = 0.024); this modest association persisted 1 year after transplant (r = -0.39; p = 0.0085). Patients with a baseline FFR <0.90 (a prognostically validated cutoff) had significantly higher baseline ADMA levels (0.63 ± 0.16 vs 0.54 ± 0.12 µM; p = 0.034). Baseline ADMA (odds ratio 1.80 per 0.1 µM; 95% confidence interval 1.07 to 3.03; p = 0.027) independently predicted a baseline FFR <0.90 after multivariable adjustment. Even after dichotomizing ADMA (≥0.60 µM, provides greatest diagnostic accuracy by receiver operating characteristic curve), this association remained significant (odds ratio 7.52, 95% confidence interval 1.74 to 32.49; p = 0.006). No significant relationship between ADMA and index of microcirculatory resistance or coronary flow reserve was detected. In conclusion, baseline ADMA was a strong independent predictor of FFR <0.90, suggesting that elevated ADMA levels are associated with abnormal epicardial function soon after heart transplantation., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: The induction of hyperemia is of importance to precisely assess the functional significance of coronary artery lesions with fractional flow reserve (FFR). Adenosine or ATP alone is used widely in this setting; however, little is known about the additive value of nicorandil, which acts as a nitrate and a K-ATP channel opener, to induce further hyperemia., Patients and Methods: A total of 183 intermediate native coronary artery lesions from 112 patients were prospectively enrolled into this study. FFR was measured using a coronary pressure wire during an intravenous ATP infusion alone (150 mcg/kg/min) (FFRATP) and repeated after an adjunctive intracoronary nicorandil injection (2.0 mg) (FFRATP+Nico)., Results: Physiologic measurements were completed without any severe adverse effects from ATP and nicorandil in all patients. FFRATP and FFRATP+Nico had a strong linear correlation (R=0.79, P<0.001). The FFR value became significantly lower with an adjunctive intracoronary nicorandil injection compared with ATP alone [FFRATP vs. FFRATP+Nico, 0.87 (interquartile range: 0.81-0.92) vs. 0.85 (0.79-0.90), P<0.001]. A total of 18 lesions out of 183 (9.8%) were reclassified after a nicorandil injection (12 from FFR>0.80 to ≤0.80 vs. six from FFR≤0.80 to >0.80, P=0.26). The adjunctive effect of nicorandil was accentuated with each increment of FFRATP strata (per 0.05 increase, P for trend<0.001), but with minimal effect around the borderline FFR zone., Conclusion: An adjunctive intracoronary nicorandil injection is safe, but appears to have little effect in inducing further hyperemia. Therefore, its effect on the clinical scenario is limited.

Background: The aim of this study is to determine the prognostic value of invasively assessing coronary physiology early after heart transplantation., Methods and Results: Seventy-four cardiac transplant recipients had fractional flow reserve, coronary flow reserve, index of microcirculatory resistance (IMR), and intravascular ultrasound performed down the left anterior descending coronary artery soon after (baseline) and 1 year after heart transplantation. The primary end point was the cumulative survival free of death or retransplantation at a mean follow-up of 4.5±3.5 years. The cumulative event-free survival was significantly lower in patients with a fractional flow reserve <0.90 at baseline (42% versus 79%; P=0.01) or an IMR ≥20 measured 1 year after heart transplantation (39% versus 69%; P=0.03). Patients in whom IMR decreased or did not change from baseline to 1 year had higher event-free survival compared with patients with an increase in IMR (66% versus 36%; P=0.03). Fractional flow reserve <0.90 at baseline (hazard ratio, 0.13; 95% confidence interval, 0.02-0.81; P=0.03), IMR ≥20 at 1 year (hazard ratio, 3.93; 95% confidence interval, 1.08-14.27; P=0.04), and rejection during the first year (hazard ratio, 6.00; 95% confidence interval, 1.56-23.09; P=0.009) were independent predictors of death/retransplantation, whereas intravascular ultrasound parameters were not., Conclusions: Invasive measures of coronary physiology (fractional flow reserve and IMR) determined early after heart transplantation are significant predictors of late death or retransplantation., (© 2016 American Heart Association, Inc.)

Background: Fractional flow reserve (FFR)-guided percutaneous coronary intervention (PCI) significantly improves outcomes compared with angio-guided PCI in patients with multivessel coronary artery disease. However, there is a theoretical concern that in patients with reduced left ventricular ejection fraction (EF) FFR may be less accurate and FFR-guided PCI less beneficial., Methods: From the FAME (Fractional flow reserve versus Angiography for Multivessel Evaluation) trial database, we compared FFR values between patients with reduced EF (both ≤ 40%, n = 90 and ≤ 50%, n = 252) and preserved EF (> 40%, n = 825 and > 50%, n = 663) according to the angiographic stenosis severity. We also compared differences in 1 year outcomes between FFR- vs. angio-guided PCI in patients with reduced and preserved EF., Results: Both groups had similar FFR values in lesions with 50-70% stenosis (p = 0.49) and with 71-90% stenosis (p = 0.89). The reduced EF group had a higher mean FFR compared to the preserved EF group across lesions with 91-99% stenosis (0.55 vs. 0.50, p = 0.02), although the vast majority of FFR values remained ≤ 0.80. There was a similar reduction in the composite end point of death, nonfatal myocardial infarction, and repeat revascularization with FFR-guided compared to angio-guided PCI for both the reduced (14.5% vs. 19.0%, relative risk = 0.76, p = 0.34) and the preserved EF group (13.8 vs. 17.0%, relative risk = 0.81, p = 0.25). The results were similar with an EF cutoff of 40%., Conclusion: Reduced EF has no influence on the FFR value unless the stenosis is very tight, in which case a theoretically explainable, but clinically irrelevant overestimation might occur. As a result, FFR-guided PCI remains beneficial regardless of EF., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Objectives: This study investigated sex differences in coronary flow reserve (CFR) and the index of microcirculatory resistance (IMR) in patients with angina in the absence of obstructive coronary artery disease., Background: Coronary microvascular dysfunction is associated with worse long-term outcomes, especially in women. Coronary flow reserve (CFR) and the index of microcirculatory resistance (IMR) are 2 methods of assessing the coronary microcirculation., Methods: We prospectively enrolled 117 women and 40 men with angina in the absence of obstructive coronary artery disease. We performed CFR, IMR, fractional flow reserve, and quantitative coronary angiography in the left anterior descending artery. Coronary flow was assessed with a thermodilution method by obtaining mean transit time (Tmn) (an inverse correlate to absolute flow) at rest and hyperemia., Results: All patients had minimal atherosclerosis by quantitative coronary angiography (% diameter stenosis: 23.2 ± 12.3%), and epicardial disease was milder in women (fractional flow reserve: 0.88 ± 0.04 vs. 0.87 ± 0.04; p = 0.04). IMR was similar between the sexes (20.7 ± 9.8 vs. 19.1 ± 8.0; p = 0.45), but CFR was lower in women (3.8 ± 1.6 vs. 4.8 ± 1.9; p = 0.004). This was primarily due to a shorter resting Tmn in women (p = 0.005), suggesting increased resting coronary flow, whereas hyperemic Tmn was identical (p = 0.79). In multivariable analysis, female sex was an independent predictor of lower CFR and shorter resting Tmn., Conclusions: Despite similar microvascular function in women and men by IMR, CFR is lower in women. This discrepancy appears to be due to differences in resting coronary flow between the sexes. The effect of sex differences should be considered in interpretation of physiological indexes using resting coronary flow., (Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)