Use Of Fractional Flow Reserve Research Articles

Fractional Flow Reserve (FFR) and Resting Index (dPR) Reproducibility With a Fiber-Optic Pressure Wire (Readi-Epic 14)

There are limited data regarding comparative prognosis and medical cost between fractional flow reserve (FFR)–based and angiography-based percutaneous coronary intervention (PCI) among revascularized patients.This study evaluates prognosis and medical cost of FFR use in revascularized patients by PCI.Using the National Health Insurance Service database, stable or unstable angina patients who underwent PCI from 2011 to 2017 were evaluated. Eligible patients were divided into 2 groups according to use of FFR in PCI. Primary outcome was a composite of all-cause death or spontaneous myocardial infarction (MI). Secondary outcomes included individual components of the primary outcome, unplanned revascularization, and medical costs.Among 134,613 eligible patients, PCI was performed based on angiography (n = 129,497) and FFR (n = 5,116). During the study period, both the annual number and proportion of use of FFR in PCI increased (all P for trend <0.001). The FFR group showed significantly lower risk of the primary outcome (7.0% vs 9.5%; P < 0.001), all-cause death (5.8% vs 7.7%; P = 0.001), and spontaneous MI (1.6% vs 2.2%; P = 0.022) than the angiography group. Although the FFR group showed higher medical cost during index admission than angiography group (median: $6,265.10 vs $5,385.60; P < 0.001), cumulative medical cost after index admission was significantly lower ($2,696.50 vs. $3,142.10; P < 0.001).Use of FFR in PCI in stable or unstable angina patients showed significantly lower risk of all-cause death and spontaneous MI compared to angiography-based PCI. Although the FFR group had higher initial medical cost than the angiography group, cumulative medical cost after index admission was significantly lower.

The association between provider characteristics and post-catheterization interventions.

ObjectivesTo examine whether the demographics of providers’ prior year patient cohorts, providers’ historic degree of catheter-based fractional flow reserve (FFR) utilization, and other provider characteristics were associated with post-catheterization performance of percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG).Study designA retrospective, observational analysis of outpatient claims data was performed.MethodsAll 2018 outpatient catheterization claims from a national organization offering commercial and Medicare Advantage health plans were examined. Claims were excluded if the patient had a prior catheterization in 2018, had any indications of CABG or valvular heart disease in the prior year of claims, or if the provider had ≤10 catheterization claims in 2017. Downstream PCI and CABG were determined by examining claims 0–30 days post-catheterization. Using multivariate mixed effects logistic regression with provider identity random effects, the association between post-catheterization procedures and provider characteristics was assessed, controlling for patient characteristics.ResultsThe sample consisted of 31,920 catheterization claims pertaining to procedures performed by 964 providers. Among the catheterization claims, 8,554 (26.8%) were followed by PCI and 1,779 (5.6%) were followed by CABG. Catheterizations performed by providers with older prior year patient cohorts were associated with higher adjusted odds of PCI (1.78; CI: 1.26–2.53), even after controlling for patient age. Catheterizations performed by providers with greater historic use of FFR had significantly higher adjusted odds of being followed by PCI (1.73; CI: 1.26–2.37).ConclusionProvider characteristics may impact whether patients receive a procedure post-catheterization. Further research is needed to characterize this relationship.

Fractional Flow Reserve in Choosing the Tactics of Interventional Treatment of Multilevel Coronary Artery Lesions

When choosing tactics for the treatment of patients with stable coronary artery disease, invasive coronary angiography remains the gold standard for diagnosis and is a crucial method in choosing tactics and volume of revascularization. However, in the presence of borderline (&gt;50-70%), multilevel lesions of the coronary artery, there is a need for additional assessment of the physiological significance of each stenosis.&#x0D; The aim. To develop an algorithm to optimize the use of fractional flow reserve (FFR) measurement in interventional treatment of borderline (&gt;50-70%), multilevel lesions of coronary arteries, to show the safety of “functional revascula­ rization” in comparison with traditional angiography.&#x0D; Materials and methods. The study included 32 patients who were treated at the National Amosov Institute of Cardiovascular Surgery in the period from 2017 to 2021 (the vast majority were men – 25 patients (67%) and 7 (33%) women) aged 60.3±8.3 years who had &gt;50-75% multilevel lesions of one of the main coronary arteries according to selective invasive coronary angiography. The patients were divided into two groups: 1) Angiographic group (n = 17, 53%), where the volume and tactics of revascularization were determined only by angiography (maximum complete anatomical revascularization); 2) Functional group (n=15, 47%) (combination of angiography data and FFR measurement, the so-called “functional revascularization”).&#x0D; Conclusions. An effective and safe algorithm for measuring FFR in multilevel lesions (reducing the number of implanted stents) is shown.

Reliability of Fractional Flow Reserve and Instantaneous Wave-Free Ratio in Assessing Intermediate Coronary Stenosis in Patients With Atrial Fibrillation

Despite the current use of fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) for guiding revascularization in atrial fibrillation (AF), there is a lack of studies evaluating their reliability in this particular population. This retrospective study aimed to investigate the reliability of FFR and iFR in patients with AF. This retrospective study included all patients with AF undergoing FFR measurements (n=45 vessels from 36 patients) at Brugmann University Hospital, Brussels, Belgium, between 2012 and 2020 or iFR (n=18 vessels from 13 patients) and a corresponding number of patients with sinus rhythm (SR) randomly selected from the same period, benefiting from iFR (n=20 vessels from 17 patients) or FFR (n=50 vessels from 37 patients). Our main findings indicate that there is an increased beat-to-beat variability of individual iFR measures in patients with AF, compared with SR. In addition, the reproducibility of iFR on test-retest is low in patients with AF, leading to increased lesion reclassification (53.8% of lesions reclassified on 2 consecutive iFR measurements in AF vs 6.6% lesions reclassified in SR, p <0.05). In contrast, FFR seems to be more robust in evaluating coronary lesions in AF in terms of equivalent variability, reproducibility, and lesion reclassification observed in the SR population. In conclusion, this is the first study to evaluate the reliability of iFR and FFR in AF. Our findings raise caution in using iFR to guide revascularization in patients with AF, whereas FFR seems to be more robust in this population.

Virtual (Computed) Fractional Flow Reserve: Future Role in Acute Coronary Syndromes.

The current management of acute coronary syndromes (ACS) is with an invasive strategy to guide treatment. However, identifying the lesions which are physiologically significant can be challenging. Non-invasive imaging is generally not appropriate or timely in the acute setting, so the decision is generally based upon visual assessment of the angiogram, supplemented in a small minority by invasive pressure wire studies using fractional flow reserve (FFR) or related indices. Whilst pressure wire usage is slowly increasing, it is not feasible in many vessels, patients and situations. Limited evidence for the use of FFR in non-ST elevation (NSTE) ACS suggests a 25% change in management, compared with traditional assessment, with a shift from more to less extensive revascularisation. Virtual (computed) FFR (vFFR), which uses a 3D model of the coronary arteries constructed from the invasive angiogram, and application of the physical laws of fluid flow, has the potential to be used more widely in this situation. It is less invasive, fast and can be integrated into catheter laboratory software. For severe lesions, or mild disease, it is probably not required, but it could improve the management of moderate disease in 'real time' for patients with non-ST elevation acute coronary syndromes (NSTE-ACS), and in bystander disease in ST elevation myocardial infarction. Its practicability and impact in the acute setting need to be tested, but the underpinning science and potential benefits for rapid and streamlined decision-making are enticing.

Prognostic value of a novel index: computational pressure-flow dynamics derived fractional flow reserve in patients with stable coronary artery disease treated with optimal medical therapy alone

Abstract Background The use of fractional flow reserve (FFR) is limited due to the need of invasive pressure wire and hyperaemic stimulus. Computational pressure-flow dynamics derived fractional flow reserve (caFFR) is a novel non-invasive index to determine the FFR in patients with stable coronary artery disease (CAD). Purpose The clinical value of caFFR remains uncertain. The aim of the study is to evaluate the prognostic role of caFFR in patients with stable CAD who were treated by optimal medical therapy alone. Methods A total of 558 stable CAD patients (mean age=64.5±11.2, 59.0% male) with ≥1 coronary lesion detected during conventional coronary angiogram were included. All of them did not undergo percutaneous coronary intervention and were treated with optimal medical therapy alone. Patients were then classified into 4 groups according to their caFFR value; caFFR ≤0.70 (n=40), caFFR = 0.71–0.80 (n=28), caFFR = 0.81–0.90 (n=292), caFFR = 0.91–1.00 (n=198), with a lower caFFR indicating a greater magnitude of myocardial ischemia. The primary endpoint was 3-year major adverse cardiac events (MACE), defined as a composite of all-cause mortality, myocardial infarction or any unplanned revascularization. Results During a median follow-up of 36 months, a total of 49 composite events occurred, including 27 all-cause mortality, 4 myocardial infarction and 18 unplanned revascularization. After multivariate adjustment, caFFR was an independent predictor of MACE (adjusted hazard ratio [HR] = 0.97 per 0.01 increase in caFFR; 95% confidence interval [Cl], 0.95–0.99; P&amp;lt;0.01), all-cause mortality (adjusted HR = 0.96 per 0.01 increase in caFFR; 95% Cl, 0.94–0.99; P&amp;lt;0.01), and stroke (adjusted HR = 0.95 per 0.01 increase in caFFR; 95% Cl, 0.90–0.99; P=0.03). The area under the curve (AUC) by receiver-operating characteristic curve analysis (ROC) is 0.70 (95% Cl, 0.62–0.78; P&amp;lt;0.01). The optimal cut-off of caFFR defined by ROC analysis for predicting MACE is 0.80, concluding that patients with caFFR ≤0.80 have significantly higher adverse event rate, which is consistent with the cut-off from wire-based FFR. Using caFFR = 0.91–1.00 as reference, the risk of MACE was highest in patients with caFFR ≤0.70 (adjusted HR = 4.65; 95% Cl, 1.81–11.94; P&amp;lt;0.01), followed by caFFR = 0.71–0.80 (adjusted HR = 3.67; 95% Cl, 1.12–11.33; P=0.02). The risk of MACE was nonetheless similar among patients with caFFR &amp;gt;0.8 (adjusted HR = 1.39; 95% Cl, 0.61–3.19, P=0.44). Conclusion In patients with stable CAD who were treated with optimal medical therapy alone, those with more significant myocardial ischemia, indicated by lower caFFR, had higher risks of adverse outcomes. The finding thus supports the use of this non invasive index to quantify the severity of myocardial ischemia, improve risk-stratification, and predict adverse outcomes in patients with stable CAD. Funding Acknowledgement Type of funding sources: Public hospital(s). Main funding source(s): The University of Hong Kong, Queen Mary Hospital

Association between non-wire based computational angiography fractional flow reserve treatment threshold and major adverse cardiac events in patients with stable coronary artery disease

Abstract Introduction Despite class IA guideline recommendations, the use of fractional flow reserve (FFR) in guiding percutaneous coronary intervention (PCI) in stable coronary artery disease (CAD) patients remains low due to limitations including the need of guidewire placement and hyperaemic stimulus. A novel non-invasive index, computational pressure-flow dynamics derived FFR (caFFR), was developed for measuring functional myocardial ischemia and overcoming the limitations of FFR. However, the clinical relevance of caFFR remains to be investigated. In the present study, we aim at evaluating the prognostic value of caFFR among stable CAD patients. Methods We retrospectively included patients with stable CAD who underwent coronary angiography during 2014–2016 at our center. Based on the caFFR value, patients were considered to be ischemic (caFFR ≤0.8) and non-ischemic (caFFR &amp;gt;0.8). Further, we recombined the patients to form the adherence cohort, where patients were defined as adherent-to-caFFR if they were ischemic with PCI or non-ischemic without PCI, and nonadherent-to-caFFR if they were ischemic without PCI or non-ischemic with PCI. The primary endpoint was major adverse cardiac events (MACE), defined as a composite of all-cause mortality, non-fatal myocardial infarction, and any revascularization. Inverse probability of treatment weighting was used to account for treatment selection bias (PCI vs without PCI, or adherent vs non-adherent), and Cox proportional hazard model was used to evaluate the association with MACE. Results A total of 1322 patients, 782 patients in the ischemic cohort and 540 patients in the non-ischemic cohort respectively, were included in our analysis. PCI was associated with a lower risk of MACE in the ischemic cohort (hazard ratio [HR] 0.52; 95% confidence interval [CI], 0.34–0.80; P=0.002), but was not associated with MACE in the non-ischemic cohort. In the adherence cohort, adherent-to-caFFR group (n=803) had a lower risk of MACE compared with nonadherent-to-caFFR group (n=566) (HR, 0.61; 95% CI, 0.44–0.85; P=0.003). Conclusion Our study is the first to demonstrate the prognostic value of caFFR, a non-wire based assessment of myocardial ischemia, in patients with stable CAD undergoing PCI. These findings support the use of caFFR that bears the potential of a wider adoption compared with wire-based FFR through a reduction in procedure time, risk and costs. Funding Acknowledgement Type of funding sources: None. Weighted Kaplan-Meier curvesWeighted Cox proportional hazards model

The relationship between coronary stenosis morphology and fractional flow reserve: a computational fluid dynamics modelling study.

AimsInternational guidelines mandate the use of fractional flow reserve (FFR) and/or non-hyperaemic pressure ratios to assess the physiological significance of moderate coronary artery lesions to guide revascularization decisions. However, they remain underused such that visual estimation of lesion severity continues to be the predominant decision-making tool. It would be pragmatic to have an improved understanding of the relationship between lesion morphology and haemodynamics. The aim of this study was to compute virtual FFR (vFFR) in idealized coronary artery geometries with a variety of stenosis and vessel characteristics.Methods and resultsCoronary artery geometries were modelled, based upon physiologically realistic branched arteries. Common stenosis characteristics were studied, including % narrowing, length, eccentricity, shape, number, position relative to branch, and distal (myocardial) resistance. Computational fluid dynamics modelling was used to calculate vFFRs using the VIRTUheart™ system. Percentage lesion severity had the greatest effect upon FFR. Any ≥80% diameter stenosis in two views (i.e. concentric) was physiologically significant (FFR ≤ 0.80), irrespective of length, shape, or vessel diameter. Almost all eccentric stenoses and all 50% concentric stenoses were physiologically non-significant, whilst 70% uniform concentric stenoses about 10 mm long straddled the ischaemic threshold (FFR 0.80). A low microvascular resistance (MVR) reduced FFR on average by 0.05, and a high MVR increased it by 0.03.ConclusionUsing computational modelling, we have produced an analysis of vFFR that relates stenosis characteristics to haemodynamic significance. The strongest predictor of a positive vFFR was a concentric, ≥80% diameter stenosis. The importance of MVR was quantified. Other lesion characteristics have a limited impact.

Evaluating the Impact of Fractional Flow Reserve (FFR) on Decision-Making for Treatment of Borderline Coronary Artery Lesions:

Background: The primary reference criterion for evaluating coronary artery stenosis functional significance is fractional flow reserve (FFR). It helps the interventionist to define appropriate angiographic borderline coronary lesions that should or should not be treated with a stent. Objective: To evaluate the experience of the cardiology department, MUST University, on the use of FFR and its impact on patients with a borderline coronary lesion as regard revascularization decision-making. Patients and methods: A retrospective study were done on 86 patients with borderline lesions undergoing coronary angiograms for whom FFR was performed. Three experienced cardiac interventionists re-analyzed their coronary angiography and whether to delay or conduct revascularization with borderline stenotic lesions (40-70 %). A distinction was made between the findings of quantitative coronary angiography (QCA), visual and functional assessment of coronary stenosis severity. Result: Eighty-six patients (51 males and 35 females) with a mean age of 58.60 ± 9.20 were enrolled in the current study. FFR was 0.8 left main (LM) lesion and for the other vessels with severe coronary lesions, stenting was performed. Conclusion: In patients having borderline coronary artery stenosis, FFR is an important tool for clinical decisions making about procedures of revascularization. FFR results in alteration in the coronary intervention judgment.

Health-Related Quality of Life and Angina in Fractional Flow Reserve- Versus Angiography-Guided Coronary Artery Bypass Grafting: FARGO Trial (Fractional Flow Reserve Versus Angiography Randomization for Graft Optimization).

In coronary artery bypass grafting (CABG), the use of fractional flow reserve (FFR) is insufficiently investigated. Stenosis assessment usually relies on visual estimates of lesion severity. This study evaluated health-related quality of life (HRQoL) and angina after FFR- versus angiography-guided CABG. One hundred patients referred for CABG were randomized to FFR- or angiography-guided CABG. In the FFR group, lesions with FFR>0.80 were deferred, while the surgeon was blinded to the FFR values in the angiography group. Before and 6 months after CABG, HRQoL was assessed by the health state classifier EQ-5D of the EuroQoL 5-level instrument and angina status based on the Canadian Cardiovascular Society classification system were registered. Six-month angiography included FFR evaluations of deferred lesions. In total, completed EQ-5D of the EuroQoL 5-level instrument questionnaires were available in 86 patients (43 in the FFR versus 43 in the angiography-guided group). HRQoL was significantly improved and angina significantly decreased from baseline to 6 months after CABG with no difference between the randomization groups. Graft failure rates and clinical outcomes were similar in both groups. Patients with graft failure or FFR<0.80 of the previous deferred lesions had significantly lower visual analogue scale scores (78.7±14.2 versus 86.8±14.7, P=0.004) and more angina compared with patients without graft failure or FFR≥0.80 at 6-month follow-up. FFR- versus angiography-guided CABG demonstrated similar improvements in HRQoL and angina 6 months after CABG. Graft failure or low FFR in deferred lesions were associated with low HRQoL and angina. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02477371.

INCREASED EXPOSURE TO X-RAYS DURING CORONARY ANGIOGRAPHY AND PERCUTANEOUS CORONARY INTERVENTIONS ASSOCIATED WITH FRACTIONAL FLOW RESERVE MEASUREMENT AND ENDOCORONARY IMAGING TECHNIQUES.

Growing use of fractional flow reserve (FFR) and intracoronary imaging techniques by optical coherence tomography or intravascular ultrasound has raised concerns about additional exposure during coronary angiography and percutaneous coronary interventions (PCIs). Using data from the prospective CRAC-France PCI Prospective Multicentre registry, we sought to evaluate the effect of these new techniques on the radiation dose to patients undergoing coronary procedures. Data on Kerma Area Product (PKA), total air kerma (KAr) and fluoroscopy time from 42182 coronary procedures were retrospectively compared, using multivariable linear regression, according to whether they included FFR and intracoronary imaging. In coronary angiography, FFR was associated with longer fluoroscopy time and higher PKA (21.0 vs. 18.9Gy.cm2) and KAr (372 vs. 299mGy) (all p<0.001). Intracoronary imaging was associated with longer fluoroscopy time, higher contrast volume (both p<0.001), lower PKA (18.3 vs. 19.0Gy.cm2, p=0.02) and similar KAr. In PCI, FFR was associated with a moderate increase in KAr (682 vs. 626mGy, p<0.01) but not PKA (35.9 vs. 33.7Gy.cm2, p=0.34). For intracoronary imaging, there were no differences between groups, except for contrast volume. Increased patient exposure associated with FFR and intracoronary imaging is moderate in diagnostic coronary angiography and minimal or none in PCI, provided optimization techniques are used. It should not be a limitation on the use of these techniques given the important additional information they provide.

Diagnostic accuracy of quantitative flow ratio for assessment of coronary stenosis significance from a single angiographic view: A novel method based on bifurcation fractal law.

We aimed to evaluate the diagnostic accuracy of computation of fractional flow reserve (FFR) from a single angiographic view in patients with intermediate coronary stenosis. Computation of quantitative flow ratio (QFR) from a single angiographic view might increase the feasibility of routine use of computational FFR. In addition, current QFR solutions assume a linear tapering of the reference vessel size, which might decrease the diagnostic accuracy in the presence of the physiologically significant bifurcation lesions. An artificial intelligence algorithm was proposed for automatic delineation of lumen contours of major epicardial coronary arteries including their side branches. A step-down reference diameter function was reconstructed based on the Murray bifurcation fractal law and used for QFR computation. Validation of this Murray law-based QFR (μQFR) was performed on the FAVOR II China study population. The μQFR was computed separately in two angiographic projections, starting with the one with optimal angiographic image quality. Hemodynamically significant coronary stenosis was defined by pressure wire-derived FFR ≤0.80. The μQFR was successfully computed in all 330 vessels of 306 patients. There was excellent correlation (r = 0.90, p < .001) and agreement (mean difference = 0.00 ± 0.05, p = .378) between μQFR and FFR. The vessel-level diagnostic accuracy for μQFR to identify hemodynamically significant stenosis was 93.0% (95% CI: 90.3 to 95.8%), with sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, and negative likelihood ratio of 87.5% (95% CI: 80.2 to 92.8%), 96.2% (95% CI: 92.6 to 98.3%), 92.9% (95% CI: 86.5 to 96.9%), 93.1% (95% CI: 88.9 to 96.1%), 23.0 (95% CI: 11.6 to 45.5), 0.13 (95% CI: 0.08 to 0.20), respectively. Use of suboptimal angiographic image view slightly decreased the diagnostic accuracy of μQFR (AUC = 0.97 versus 0.92, difference = 0.05, p < .001). Intra- and inter-observer variability for μQFR computation was 0.00 ± 0.03, and 0.00 ± 0.03, respectively. Average analysis time for μQFR was 67 ± 22 s. Computation of μQFR from a single angiographic view has high feasibility and excellent diagnostic accuracy in identifying hemodynamically significant coronary stenosis. The short analysis time and good reproducibility of μQFR bear potential of wider adoption of physiological assessment in the catheterization laboratory.

Usefulness of Fractional Flow Reserve during Routine Clinical Procedures in All-Comer Coronary Artery Disease Patients

Background: Fractional flow reserve (FFR)-guided interventions, though proved to be safe, continue to be a much-underutilized modality in determining treatment strategy, and data is lacking in Indian population. Objective: We aimed to determine the use of FFR-guided PCI and assess the overall impact on treatment decisions and clinical outcomes in patients with acute coronary syndrome (ACS) or chronic coronary syndromes (CCS). Methods: In this single-center retrospective and prospective observational study, FFR had been performed for the evaluation of treatment reclassification and clinical outcomes, as per physician’s clinical practice. Results: Data was obtained for 250 subjects (mean age 60.45 ± 9.6 years) with 324 lesions. The treatment plan based on angiography alone changed in 28% of lesions post-hyperemic FFR. The initial treatment plan based on angiography vs. the final treatment plan post-FFR (>0.80) was medical management 56.5% vs. 66.0%; CABG 11.1% vs. 7.7%; and PCI 32.4% vs. 26.2%. In subjects initially assigned to medical management, 14% had changed to PCI, and for subjects initially assigned to PCI, 44% had changed to medical therapy. Receiver operating characteristics (ROC) curve analysis revealed a good correlation between a resting FFR value of Conclusion: This study supports the use of FFR in determining treatment strategy in ACS or CCS patients with low MACE. Resting FFR value of be an alternative to intracoronary nitroglycerine/adenosine/Nikorandil-induced FFR in predicting positive FFR particularly in hemodynamically unstable patients, and who are intolerant to hyperemic drugs.

Abstract 13674: Real-world Outcomes Following Fractional Flow Reserve Use

Introduction: Fractional flow reserve is an established method for assessing coronary artery stenosis severity. However, long-term outcome data in a real-world population is lacking. Aims: We aim to determine whether FFR use is superior to angiography alone in relation to cardiac death and all-cause death in a real-world population. Methods: Patients undergoing angiography between June-2017 and June-2018 recorded by the Centre-for-Health-Record-Linkage (CHeReL) were included. The CHeReL database captures health data from ≥97% of all healthcare facilities in the state of New South Wales, with a population of 7.5 million people. The cohort was stratified into angiography-FFR group when concomitant FFR was performed, and the angiography-only group which included all patients undergoing angiography without concomitant FFR. The primary and secondary outcomes were cardiac death and all-cause death respectively. Results: The study cohort comprised 34,597 patients, in which 32,863 (95%) patients underwent angiography alone and 1,734 (5%) patients had angiography combined with FFR. At 1-year follow-up, the angiography-FFR group had a lower occurrence of the endpoints of cardiac death (0.8% vs 2.3%, P&lt;0.001) and all-cause death (1.7% vs 4.7%, P&lt;0.001) compared to the angiography-only group. Multivariable Cox regression analysis showed FFR use to be associated with lower rates of both cardiac death (hazard ratio [HR] 0.55, 95% confidence interval [CI] 0.32-0.93, P=0.025) and all-cause death (HR 0.55, 95% CI 0.38-0.79, P=0.001) independent of age, sex, facility, country of birth, referral source, marital status, Charlson comorbidity index, valvular heart disease, pre-existing atrial fibrillation (AF), presenting illnesses including AF, congestive heart failure or acute coronary syndrome, planned percutaneous coronary intervention or coronary artery bypass graft surgery, and concomitant or subsequent cardiac valve surgery. Conclusions: FFR use was associated with a reduction in both cardiac death and all-cause death in this real-world study.

Non-hyperaemic pressure ratios to guide percutaneous coronary intervention.

The use of fractional flow reserve (FFR) in guiding revascularisation improves patient outcomes and has been well-established in clinical guidelines. Despite this, the uptake of FFR has been limited, likely attributable to the perceived increase in procedural time and use of hyperaemic agents that can cause patient discomfort. This has led to the development of instantaneous wave-free ratio (iFR), an alternative non-hyperaemic pressure ratio (NHPR). Since its inception, the use of iFR has been supported by an increasing body of evidence and is now guideline recommended. More recently, other commercially available NHPRs including diastolic hyperaemia-free ratio and resting full-cycle ratio have emerged. Studies have demonstrated that these indices, in addition to mean distal coronary artery pressure to mean aortic pressure ratio, are mathematically analogous (with specific nuances) to iFR. Additionally, there is increasing data demonstrating the equivalent diagnostic performance of alternative NHPRs in comparison with iFR and FFR. These NHPRs are now integral within most current pressure wire systems and are commonly available in the catheter laboratory. It is therefore key to understand the fundamental differences and evidence for NHPRs to guide appropriate clinical decision-making.

Survival of Patients With Angina Pectoris Undergoing Percutaneous Coronary Intervention With Intracoronary Pressure Wire Guidance

BackgroundIntracoronary pressure wire measurement of fractional flow reserve (FFR) provides decision-making guidance during percutaneous coronary intervention (PCI). However, limited data exist on the effect of FFR on long-term clinical outcomes in patients with stable angina pectoris. ObjectivesThe purpose of this study was to determine the association between the usage of FFR and all-cause mortality in patients with stable angina undergoing PCI. MethodsData was used from the SCAAR (Swedish Coronary Angiography and Angioplasty Registry) on all patients undergoing PCI (with or without FFR guidance) for stable angina pectoris in Sweden between January 2005 and March 2016. The primary endpoint was all-cause mortality, and the secondary endpoints were stent thrombosis (ST) or restenosis and peri-procedural complications. The primary model was multilevel Cox proportional hazards regression adjusted with Kernel-based propensity score matching. ResultsIn total, 23,860 patients underwent PCI for stable angina pectoris; of these, FFR guidance was used in 3,367. After a median follow-up of 4.7 years (range 0 to 11.2 years), the FFR group had lower adjusted risk estimates for all-cause mortality (hazard ratio: 0.81; 95% confidence interval [CI]: 0.73 to 0.89; p < 0.001), and ST and restenosis (hazard ratio: 0.74; 95% CI: 0.57 to 0.96; p = 0.022). The number of peri-procedural complications did not differ between the groups (adjusted odds ratio: 0.96; 95% CI: 0.77 to 1.19; p = 0.697). ConclusionsIn this observational study, the use of FFR was associated with a lower risk of long-term mortality, ST, and restenosis in patients undergoing PCI for stable angina pectoris. This study supports the current European and American guidelines for the use of FFR during PCI and shows that intracoronary pressure wire guidance confers prognostic benefit in patients with stable angina pectoris.

Angiography-Derived Fractional Flow Reserve: More or Less Physiology?

Evidence robustly demonstrates that ischemia, rather than anatomy, is the optimal target for coronary revascularization. In the cardiac catheter laboratory, fractional flow reserve (FFR) and corresponding diastolic indices are regarded as the gold standard for physiological lesion assessment and ischemia detection (Table 1). Yet, despite a wealth of supporting data and indications in international guidelines, the use of FFR remains surprisingly low in the diagnostic assessment of coronary artery disease across the world.1, 2 To address this, multiple groups have developed methods for computing FFR from invasive angiography, without the need for passing a pressure wire or inducing hyperemia, thus removing the main barriers to uptake. Angiography‐derived FFR therefore has the potential to extend the benefits of physiological coronary lesion assessment to considerably more patients. Given the size of the interventional cardiology market, clinical and commercial motivation to deliver these tools as quickly as possible could hardly be greater. Several models are now approved as medical devices. Imminently, physicians and healthcare providers will have to decide whether to use these tools. But do they truly deliver physiology, and are they accurate enough? There are 3 particular areas of that deserve close scrutiny.

European survey on acute coronary syndrome diagnosis and revascularisation treatment: Assessing differences in reported clinical practice with a focus on strategies for specific patient cases.

Rationale, Aims, and ObjectivesWhile different imaging and treatment options are available in acute coronary syndrome (ACS) care, there is a lack of data regarding their use across Europe. We examined the diagnostic and treatment strategies in patients with known or suspected ACS as reported by physicians and identified variations in responses across European countries and geographical areas.MethodA web‐based clinician survey focusing on ACS imaging and revascularization treatments was circulated through email distribution lists and websites of European professional societies in the field of cardiology. We collected information on respondents' clinical setting and specialty. Reported percentages of patients receiving imaging or treatment modalities and percentages of clinicians reporting to use modalities in a range of clinical scenarios were analyzed. Statistical comparisons were performed.ResultsIn total, 69 responses were received (Sweden [n = 20], United Kingdom [n = 16], Northern/Western Europe [n = 17], Southern Europe [n = 9], and Central Europe [n = 7]). Considerable variations between geographical areas were seen in terms of reported diagnostic modalities and treatment strategies. For example, when presented with the scenario of a theoretical 45‐year‐old smoking female with a suspected ACS, 56% of UK clinicians reported to use coronary computed tomography angiography, compared to only 10% of Swedish clinicians (P = .002). Large variations were observed regarding the reported use of fractional flow reserve by physicians for non‐culprit lesions during invasive management of myocardial infarction patients (44% in Sweden, 31% in the United Kingdom, and 30% in Northern/Western Europe vs non‐use in Central and Southern Europe).ConclusionsIn this survey, respondents reported different diagnostic and treatment strategies in ACS care. These variations seem to have geographic components. Larger studies or real world data are needed to verify these observations and investigate their causes. More research is needed to compare the quality and efficiency of ACS care across countries and explore pathways for improvement.

Utilization and Outcomes of Measuring Fractional Flow Reserve in Patients With Stable Ischemic Heart Disease

BackgroundThe use and clinical outcomes of fractional flow reserve (FFR) measurement in patients with stable ischemic heart disease (SIHD) are uncertain, as prior studies have been based on selected populations. ObjectivesThis study sought to evaluate contemporary, real-world patterns of FFR use and its effect on outcomes among unselected patients with SIHD and angiographically intermediate stenoses. MethodsThe authors used data from the Veterans Affairs Clinical Assessment, Reporting, and Tracking (CART) Program to analyze patients who underwent coronary angiography between January 1, 2009, and September 30, 2017, and had SIHD with angiographically intermediate disease (40% to 69% diameter stenosis on visual inspection). The authors documented trends in FFR utilization and evaluated predictors using generalized mixed models. They applied Cox proportional hazards models to determine the association between an FFR-guided revascularization strategy and all-cause mortality at 1 year. ResultsA total of 17,989 patients at 66 sites were included. The rate of FFR use gradually increased from 14.8% to 18.5% among all patients with intermediate lesions, and from 44% to 75% among patients who underwent percutaneous coronary intervention. One-year mortality was 2.8% in the FFR group and 5.9% in the angiography-only group (p < 0.0001). After adjustment for patient, site-level, and procedural factors, FFR-guided revascularization was associated with a 43% lower risk of mortality at 1 year compared with angiography-only revascularization (hazard ratio: 0.57; 95% confidence interval: 0.45 to 0.71; p < 0.0001). ConclusionsIn patients with SIHD and angiographically intermediate stenoses, use of FFR has slowly risen, and was associated with significantly lower 1-year mortality.

Insights into the Role of Fractional Flow Reserve in Clinical Practice

The early trials of fractional flow reserve (FFR), such as the Deferral versus Performance of Percutaneous Transluminal Coronary Angioplasty in Patients Without Documented Ischaemia, FFR versus angiography for multivessel evaluation (FAME), and FAME 2 trials, established the role of FFR in the practice of interventional cardiology. These trials led proponents of FFR to propose making FFR a routine procedure before percutaneous coronary intervention (PCI) and to give preference to PCI over optimal medical therapy (OMT) in those with FFR-positive coronary stenoses. Follow-up results of these trials have given more insights. Some of the benefits of FFR-guided strategy over angiography-guided strategy disappeared over time, and beyond revascularization, the FFR strategy did not show benefit over OMT when considering death and myocardial infarction as endpoints. The FUnctional Testing Underlying Coronary REvascularization trial did not demonstrate the superiority of the FFR-guided strategy over angiography-guided strategy. The ORBITA and the ISHEMIA trials gave strength to the lifestyle modification and OMT approach in stable ischemic heart disease patients with moderate-to-severe ischemia. The role of FFR has to be defined in light of the evolving clinical advances in medicine and new evidence. An in-depth review of all current evidence provides no compelling evidence for the routine use of FFR in cardiac interventions. However, FFR can play a role in coronary stenoses where there is uncertainty in the hemodynamic impact of the lesions.