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Background: we hypothesized that fractional flow reserve (FFR)-guided percutaneous coronary intervention (PCI) would be superior to medical therapy as initial treatment in patients with stable coronary artery disease.Methods: among 1220 patients with angiographically significant stenoses, those in whom at least one stenosis was hemodynamically significant (FFR, ≤0.80) were randomly assigned to FFR-guided PCI plus medical therapy or to medical therapy alone. Patients in whom all stenoses had an FFR of more than 0.80 received medical therapy and were entered into a registry. The primary end point was a composite of death, myocardial infarction, or urgent revascularization.Results: a total of 888 patients underwent randomization (447 patients in the PCI group and 441 in the medical-therapy group). At 5 years, the rate of the primary end point was lower in the PCI group than in the medical-therapy group (13.9% vs. 27.0%; hazard ratio, 0.46; 95% confidence interval [CI], 0.34 to 0.63; PConclusions: in patients with stable coronary artery disease, an initial FFR-guided PCI strategy was associated with a significantly lower rate of the primary composite end point of death, myocardial infarction, or urgent revascularization at 5 years than medical therapy alone. Patients without hemodynamically significant stenoses had a favorable long-term outcome with medical therapy alone. (Funded by St. Jude Medical and others; FAME 2 ClinicalTrials.gov number, NCT01132495 .).

Objectives This study sought to assess the impact of a wide range of mean right atrial pressure (Pra) on fractional flow reserve (FFR) measurements. Background FFR invasively assesses the ischemic potential of coronary stenoses. FFR is calculated as the ratio of mean distal coronary pressure (Pd) to mean aortic pressure (Pa) during maximal hyperemia. The Pra is considered to have little impact if it is within normal range, so it is neglected in the formula. Methods In 1,676 stenoses of 1,235 patients undergoing left-right heart catheterization for ischemic (642 [52%]) or valvular heart disease (593 [48%]), the authors compared the FFR values calculated without accounting for Pra (FFR= Pd/Pa) to the corresponding myocardial fractional flow reserve (FFRmyo) values accounting for Pra (FFRmyo = Pd - Pra/Pa - Pra). Results The median Pra was 7 (interquartile range [IQR]: 5 to 10) mm Hg with a maximum of 27 mm Hg. The correlation and agreement between FFR and FFRmyo was excellent (R2 = 0.987; slope 1.096 ± 0.003). The median FFR (0.85; IQR: 0.78 to 0.91) was slightly but statistically significantly higher than the median FFRmyo (0.83; IQR: 0.76 to 0.90; p < 0.001) with a median difference of 0.01 (IQR: 0.01 to 0.02). Values of FFR above the cutoff of 0.80 provided an FFRmyo ≤0.80 in 110 (9%) stenoses. No FFR value above 0.80 provided an FFRmyo ≤0.75. Conclusions The difference between FFR and FFRmyo was minimal even in patients with markedly increased Pra. FFR values above the gray zone (i.e., >0.80) did not yield values below the gray zone (i.e., ≤0.75) in any case, which suggests that the impact of right atrial pressure on FFR measurement is indeed negligible.

The present study sought to establish the dosage of intracoronary (IC) adenosine associated with minimal side effects and above which no further increase in flow can be expected.

OBJECTIVES: The aim of this study was to develop a new model for assessment of stenosis severity in a bifurcation lesion including its core. The diagnostic performance of this model, powered by 3-dimensional quantitative coronary angiography to predict the functional significance of obstructive bifurcation stenoses, was evaluated using fractional flow reserve (FFR) as the reference standard.BACKGROUND: Development of advanced quantitative models might help to establish a relationship between bifurcation anatomy and FFR.METHODS: Patients who had undergone coronary angiography and interventions in 5 European cardiology centers were randomly selected and analyzed. Different bifurcation fractal laws, including Murray, Finet, and HK laws, were implemented in the bifurcation model, resulting in different degrees of stenosis severity.RESULTS: A total of 78 bifurcation lesions in 73 patients were analyzed. In 51 (65%) bifurcations, FFR was measured in the main vessel. A total of 34 (43.6%) interrogated vessels had an FFR ≤0.80. Correlation between FFR and diameter stenosis was poor by conventional straight analysis (ρ = -0.23, p < 0.001) but significantly improved by bifurcation analyses: the highest by the HK law (ρ = -0.50, p < 0.001), followed by the Finet law (ρ = -0.49, p < 0.001), and the Murray law (ρ = -0.41, p < 0.001). The area under the receiver-operating characteristics curve for predicting FFR ≤0.80 was significantly higher by bifurcation analysis compared with straight analysis: 0.72 (95% confidence interval: 0.61 to 0.82) versus 0.60 (95% confidence interval: 0.49 to 0.71, p = 0.001). Applying a threshold of ≥50% diameter stenosis, as assessed by the bifurcation model, to predict FFR ≤0.80 resulted in 23 true positives, 27 true negatives, 17 false positives, and 11 false negatives.CONCLUSIONS: The new bifurcation model provides a comprehensive assessment of bifurcation anatomy. Compared with straight analysis, identification of lesions with preserved FFR values in obstructive bifurcation stenoses was improved. Nevertheless, accuracy was limited by using solely anatomical parameters.

Objectives The aim of this study was to determine the impact of downstream coronary stenosis in the left anterior descending coronary artery (LAD) or left circumflex coronary artery (LCx) on the assessment of fractional flow reserve (FFR) across an intermediate left main coronary artery (LMCA) stenosis in humans with the pressure wire positioned in the nondiseased downstream vessel. Background Accurate assessment of intermediate LMCA disease is critical for guiding decisions regarding revascularization. In theory, FFR across an intermediate LMCA stenosis will be affected by downstream disease, even if the pressure wire is positioned in the nondiseased downstream vessel. Methods After percutaneous coronary intervention of the LAD, LCx, or both, an intermediate LMCA stenosis was created with a deflated balloon catheter. FFR was measured in the LAD and LCx coronary arteries before and after creation of downstream stenosis by inflating an angioplasty balloon within the newly placed stent. The true FFR (FFRtrue) of the LMCA, measured in the nondiseased downstream vessel in the absence of stenosis in the other vessel, was compared with the apparent FFR (FFRapp) measured in the presence of stenosis. Results In 25 patients, 91 pairs of measurements were made, 71 with LAD stenosis and 20 with LCx stenosis. FFRtrue of the LMCA was significantly lower than FFRapp (0.81 ± 0.08 vs. 0.83 ± 0.08, p < 0.001), although the numerical difference was small. This difference correlated with the severity of the downstream disease (r = 0.35, p < 0.001). In all cases in which FFRapp was >0.85, FFRtrue was >0.80. Conclusions In most cases, downstream disease does not have a clinically significant impact on the assessment of FFR across an intermediate LMCA stenosis with the pressure wire positioned in the nondiseased vessel.

ObjectivesThe present study sought to establish the dosage of intracoronary (IC) adenosine associated with minimal side effects and above which no further increase in flow can be expected.BackgroundDespite the widespread adoption of IC adenosine in clinical practice, no wide-ranging, dose-response study has been conducted. A recurring debate still exists regarding its optimal dose.MethodsIn 30 patients, Doppler-derived flow velocity measurements were obtained in 10 right coronary arteries (RCAs) and 20 left coronary arteries (LCAs) free of stenoses >20% in diameter. Flow velocity was measured at baseline and after 8 ml bolus administrations of arterial blood, saline, contrast medium, and 9 escalating doses of adenosine (4 to 500 μg). The hyperemic value was expressed in percent of the maximum flow velocity reached in a given artery (Q/Qmax, %).ResultsQ/Qmax did not increase significantly beyond dosages of 60 μg for the RCA and 160 μg for LCA. Heart rate did not change, whereas mean arterial blood pressure decreased by a maximum of 7% (p < 0.05) after bolus injections of IC adenosine. The incidence of transient A-V blocks was 40% after injection of 100 μg in the RCA and was 15% after injection of 200 μg in the LCA. The duration of the plateau reached 12 ± 13 s after injection of 100 μg in the RCA and 21 ± 6 s after the injection of 200 μg in the LCA. A progressive prolongation of the time needed to return to baseline was observed. Hyperemic response after injection of 8 ml of contrast medium reached 65 ± 36% of that achieved after injection of 200 μg of adenosine.ConclusionsThis wide-ranging, dose-response study indicates that an IC adenosine bolus injection of 100 μg in the RCA and 200 μg in the LCA induces maximum hyperemia while being associated with minimal side effects.

ObjectivesThe aim of this study was to determine the impact of downstream coronary stenosis in the left anterior descending coronary artery (LAD) or left circumflex coronary artery (LCx) on the assessment of fractional flow reserve (FFR) across an intermediate left main coronary artery (LMCA) stenosis in humans with the pressure wire positioned in the nondiseased downstream vessel.BackgroundAccurate assessment of intermediate LMCA disease is critical for guiding decisions regarding revascularization. In theory, FFR across an intermediate LMCA stenosis will be affected by downstream disease, even if the pressure wire is positioned in the nondiseased downstream vessel.MethodsAfter percutaneous coronary intervention of the LAD, LCx, or both, an intermediate LMCA stenosis was created with a deflated balloon catheter. FFR was measured in the LAD and LCx coronary arteries before and after creation of downstream stenosis by inflating an angioplasty balloon within the newly placed stent. The true FFR (FFRtrue) of the LMCA, measured in the nondiseased downstream vessel in the absence of stenosis in the other vessel, was compared with the apparent FFR (FFRapp) measured in the presence of stenosis.ResultsIn 25 patients, 91 pairs of measurements were made, 71 with LAD stenosis and 20 with LCx stenosis. FFRtrue of the LMCA was significantly lower than FFRapp (0.81 ± 0.08 vs. 0.83 ± 0.08, p < 0.001), although the numerical difference was small. This difference correlated with the severity of the downstream disease (r = 0.35, p < 0.001). In all cases in which FFRapp was >0.85, FFRtrue was >0.80.ConclusionsIn most cases, downstream disease does not have a clinically significant impact on the assessment of FFR across an intermediate LMCA stenosis with the pressure wire positioned in the nondiseased vessel.

Importance Whether the improvement in myocardial perfusion provided by percutaneous coronary intervention (PCI) is associated with symptomatic relief or improved outcomes has not been well investigated. Objective To investigate the prognostic value of the improvement in fractional flow reserve (FFR) after PCI (ΔFFR) on patients’ symptoms and 2-year outcomes. Design, Setting, and Participants This study is a post hoc analysis of data from patients undergoing FFR-guided PCI in the randomized clinical trials Fractional Flow Reserve vs Angiography for Multivessel Evaluation (FAME) 1 (NCT00267774; 2009) and FAME 2 (NCT01132495; 2012), with inclusion of 2 years of follow-up data. The FAME 1 trial included patients with multivessel coronary artery disease from 20 medical centers in Europe and the United States. The FAME 2 trial included patients with stable coronary artery disease involving up to 3 vessels from 28 sites in Europe and North America. Lesions from the group in the FAME 1 trial from whom FFR was measured and the group in the FAME 2 trial who received FFR-guided PCI plus medical therapy were analyzed. Data analysis occurred from May 2017 to May 2018. Interventions Measure of post-PCI FFR. Main Outcomes and Measures Vessel-oriented clinical events at 2 years, a composite of cardiac death, target vessel-associated myocardial infarction, and target vessel revascularization. Results This analysis included 639 patients from whom pre-PCI and post-PCI FFR values were available. Of their 837 lesions, 277 were classified into the lowest tertile (ΔFFR≤0.18), 282 into the middle tertile (0.19≤ΔFFR≤0.31), and 278 into the highest tertile (ΔFFR>0.31). Vessel-oriented clinical events were significantly more frequent in the lowest tertile (n = 25 of 277 [9.1%]) compared with the highest tertile (n = 13 of 278 [4.7%]; hazard ratio, 2.01 [95% CI, 1.03-3.92]; P = .04). In addition, a significant association was observed between ΔFFR and symptomatic relief (odds ratio, 1.33 [95% CI, 1.02-1.74]; P = .02). Conclusions and Relevance In this analysis of 2 randomized clinical trials, the larger the improvement in FFR, the larger the symptomatic relief and the lower the event rate. This suggests that measuring FFR before and after PCI provides clinically useful information.

Background Global fractional flow reserve (FFR) (ie, the sum of the FFR values in the 3 major coronary arteries) is a physiologic correlate of global atherosclerotic burden. The objective of the present study was to investigate the value of global FFR in predicting long‐term clinical outcome of patients with stable coronary artery disease but no ischemia‐inducing stenosis. Methods and Results We studied major adverse cardiovascular events (MACEs: all‐cause death, myocardial infarction, and any revascularization) after 5 years in 1122 patients without significant stenosis (all FFR >0.80; n=275) or with at least 1 significant stenosis successfully treated by percutaneous coronary intervention (ie, post–percutaneous coronary intervention FFR >0.80; n=847). The patients were stratified into low, mid, or high tertiles of global FFR (≤2.80, 2.80–2.88, and ≥2.88). Patients in the lowest tertile of global FFR showed the highest 5‐year MACE rate compared with those in the mid or high tertile of global FFR (27.5% versus 22.0% and 20.9%, respectively; log‐rank P =0.040). The higher 5‐year MACE rate was mainly driven by a higher rate of revascularization in the low global FFR group (16.4% versus 11.3% and 11.8%, respectively; log‐rank P =0.038). In a multivariable model, an increase in global FFR of 0.1 unit was associated with a significant reduction in the rates of MACE (hazard ratio [HR], 0.988; 95% CI, 0.977–0.998; P =0.023), myocardial infarction (HR, 0.982; 95% CI, 0.966–0.998; P =0.032), and revascularization (HR, 0.985; 95% CI, 0.972–0.999; P =0.040). Conclusions Even in the absence of ischemia‐producing stenoses, patients with a low global FFR, physiologic correlate of global atherosclerotic burden, present a higher risk of MACE at 5‐year follow‐up.

Aims Significant platelet activation after long stented coronary segments has been associated with periprocedural microvascular impairment and myonecrosis. In long lesions treated either with an everolimus-eluting bioresorbable vascular scaffold (BVS) or an everolimus-eluting stent (EES), we aimed to investigate (a) procedure-related microvascular impairment, and (b) the relationship of platelet activation with microvascular function and related myonecrosis. Methods and results Patients (n=66) undergoing elective percutaneous coronary intervention (PCI) in long lesions were randomised 1:1 to either BVS or EES. The primary endpoint was the difference between groups in changes of pressure-derived corrected index of microvascular resistance (cIMR) after PCI. Periprocedural myonecrosis was assessed by high-sensitivity cardiac troponin T (hs-cTnT), platelet reactivity by high-sensitivity adenosine diphosphate (hs-ADP)-induced platelet reactivity with the Multiplate Analyzer. Post-dilatation was more frequent in the BVS group, with consequent longer procedure time. A significant difference was observed between the two groups in the primary endpoint of ΔcIMR (p=0.04). hs-ADP was not different between the groups at different time points. hs-cTnT significantly increased after PCI, without difference between the groups. Conclusions In long lesions, BVS implantation is associated with significant acute reduction in IMR as compared with EES, with no significant interaction with platelet reactivity or periprocedural myonecrosis.

Background: Among patients with documented stable coronary artery disease and in whom no revascularization was performed, we compared the respective values of angiographic diameter stenosis (DS) and fractional flow reserve (FFR) in predicting natural history. Methods: The present analysis included the 607 patients from the FAME 2 trial (Fractional Flow Reserve Versus Angiography in Multivessel Evaluation 2) in whom no revascularization was performed. FFR varied from 0.20 to 1.00 (average 0.74±0.16), and DS (by quantitative coronary analysis) varied from 8% to 98% (average 53±15). The primary end point, defined as vessel-oriented clinical end point (VOCE) at 2 years, was a composite of prospectively adjudicated cardiac death, vessel-related myocardial infarction, vessel-related urgent, and not urgent revascularization. The stenoses were divided into 4 groups according to FFR and %DS values: positive concordance (FFR≤0.80; DS≥50%), negative concordance (FFR>0.80; DS0.80; DS≥50%). Results: The rate of VOCE was highest in the positive concordance group (log rank: X 2 =80.96; P =0.001) and lowest in the negative concordance group. The rate of VOCE was higher in the positive mismatch group than in the negative mismatch group (hazard ratio, 0.38; 95% confidence interval, 0.21–0.67; P =0.001). There was no significant difference in VOCE between the positive concordance and positive mismatch groups (FFR≤0.80; hazard ratio, 0.77; 95% confidence interval, 0.57–1.09; P =0.149) and no significant difference in rate of VOCE between the negative mismatch and negative concordance groups (FFR>0.80; hazard ratio, 1.89; 95% confidence interval, 0.96–3.74; P =0.067). Conclusions: In patients with stable coronary disease, physiology (FFR) is a more important determinant of the natural history of coronary stenoses than anatomy (DS). Clinical Trial Registration: URL: https://clinicaltrials.gov . Unique identifier: NCT01132495.

Aims The aim of this study was to assess prospectively the clinical benefits of fractional flow reserve (FFR) in guiding coronary artery bypass grafting (CABG). Methods and results GRAFFITI is a single-blinded, prospective, multicentre, randomised controlled trial of FFR-guided versus angiography-guided CABG. We enrolled patients undergoing coronary angiography, having a significantly diseased left anterior descending artery or left main stem and at least one more major coronary artery with intermediate stenosis, assessed by FFR. Surgical strategy was defined based on angiography, blinded to FFR values prior to randomisation. After randomisation, patients were operated on either following the angiography-based strategy (angiography-guided group) or according to FFR, i.e., with an FFR ≤0.80 as cut-off for grafting (FFR-guided group). The primary endpoint was graft patency at 12 months. Between March 2012 and December 2016, 172 patients were randomised either to the angiography-guided group (84 patients) or to the FFR-guided group (88 patients). The patients had a median of three [3; 4] lesions; diameter stenosis was 65% (50%; 80%), FFR was 0.72 (0.50; 0.82). Compared to the angiography-guided group, the FFR-guided group received fewer anastomoses (3 [3; 3] vs 2 [2; 3], respectively; p=0.004). One-year angiographic follow-up showed no difference in overall graft patency (126 [80%] vs 113 [81%], respectively; p=0.885). One-year clinical follow-up, available in 98% of patients, showed no difference in the composite of death, myocardial infarction, target vessel revascularisation and stroke. Conclusions FFR guidance of CABG has no impact on one-year graft patency, but it is associated with a simplified surgical procedure. ClinicalTrials.gov Identifier: NCT01810224.

Pressure wire-based fractional flow reserve is considered the standard of reference for evaluation of the ischemic potential of coronary stenoses and the expected benefit from revascularization. Accordingly, its application in daily practice or for research purposes has to be as standardized as possible to avoid technical or operator-related artifacts in pressure recordings. This document proposes a standardized way of acquiring, recording, interpreting, and archiving the pressure tracings for daily practice and for the purpose of clinical research involving a core laboratory. Proposed standardized steps enhance the uniformity of clinical practices and data interpretation. (C) 2016 by the American College of Cardiology Foundation. Dr. Toth has a consultancy agreement with St. Jude 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 and Volcano/Philips outside of the submitted work; and has an institutional licensing and consulting agreement with Boston Scientific. Dr. Jeremias has reported speaker and consultant fees from Volcano Inc. and St. Jude Medical Inc. outside of the submitted work. Dr. Pellicano has been supported by a research grant provided by the Cardiopath PhD program. Dr. Vranckx has received speaking or consulting fees from AstraZeneca, Bayer, Boehringer Ingelheim, Daiichi-Sankyo, and The Medicines Co. outside of the submitted work. Dr. Fearon has received research support from Medtronic and St. Jude Medical outside of the submitted work; and has received consultant fees from Medtronic, HeartFlow, and Cathworks. Dr. Barbato has received institutional research grants and speakers fees from St. Jude Medical outside of the submitted work. Dr. Kern has received consultant and speaker fees from St. Jude Medical, Volcano, Opsens, ACIST Medical, and Heartflow outside of the submitted work. Dr. Pijls is a consultant for St. Jude Medical, Opsens, and Boston Scientific outside of the submitted work; has received research grants from Medtronic; and is a shareholder for Philips, ASML, General Electric, and Heartflow. Dr. De Bruyne is a shareholder for Siemens, GE, Bayer, Philips, HeartFlow, Edwards Life Sciences, Sanofi, and Omega Pharma; and his institution has received grant support from Abbott, Boston Scientific, Biotronik, and St. Jude Medical and receives consulting fees on his behalf from St. Jude Medical, Opsens, and Boston Scientific outside of the submitted work.

Background— Fractional flow reserve (FFR)-guided coronary artery bypass graft (CABG) surgery has been associated with lower number of graft anastomoses, lower rate of on-pump surgery, and higher graft patency rate as compared with angiography-guided CABG surgery. However, no clinical benefit has been reported to date. Methods and Results— Consecutive patients (n=627) treated by CABG between 2006 and 2010 were retrospectively included. In 198 patients, at least 1 stenosis was grafted according to FFR (FFR-guided group), whereas in 429 patients all stenoses were grafted based on angiography (angiography-guided group). The 2 coprimary end points were overall death or myocardial infarction and major adverse cardiovascular events (composite of overall death, myocardial infarction, and target vessel revascularization) up to 6-year follow-up. In the FFR-guided group, patients were significantly younger (66 [57–73] versus 70 [63–76]; P P =0.008), and less often diabetic (21% versus 30%; P =0.023). Clinical follow-up (median, 85 [66–104] months) was analyzed in 396 patients after 1:1 propensity-score matching for these 3 variables. The rate of overall death or myocardial infarction was significantly lower in the FFR-guided (n=31 [16%] versus n=49 [25%]; hazard ratio, 0.59 [95% confidence interval, 0.38–0.93]; P =0.020) as compared with the angiography-guided group. Major adverse cardiovascular events rate was also numerically lower in the FFR-guided than in the angiography-guided group (n=42 [21%] versus n=52 [26%]; hazard ratio, 0.77 [95% confidence interval, 0.51–1.16]; P =0.21). Conclusions— FFR-guided CABG is associated with a significant reduction in the rate of overall death or myocardial infarction at 6-year follow-up as compared with angiography-guided CABG.

Clinical benefit of invasive functionally guided revascularization has been mostly investigated and proven for percutaneous coronary intervention. It has never been prospectively evaluated whether a systematic fractional flow reserve (FFR) assessment is also beneficial in guiding coronary artery bypass graft surgery (CABG). The objective of the GRAft patency after FFR-guided versus angiography-guIded CABG (GRAFFITI) trial was to compare an FFR-guided revascularization strategy to the traditional angiography-guided revascularization strategy for patients undergoing CABG. Patients were enrolled with significantly diseased left anterior descending or left main stem and at least one major coronary artery with angiographically intermediate stenosis (30-90% diameter stenosis) that was assessed by FFR. Thereafter, while the FFR values were kept concealed, cardiac surgeons decided their intended procedural strategy based on the coronary angiography alone. At this point, patients underwent 1:1 randomization to either an FFR-guided or an angiography-guided CABG strategy. In case the patient was randomized to angiography-guided arm, cardiac surgeons kept their intended procedural strategy, i.e., CABG was guided solely on the basis of the coronary angiography. In case the patient was randomized to the FFR-guided arm, FFR values were disclosed to the surgeons who revised the surgical protocol according to the functional significance of each coronary stenosis. The primary endpoint of the trial was the rate of graft occlusion at 12 months, assessed by coronary computed tomography or coronary angiography. The secondary endpoints were (1) length of postoperative hospital stay; (2) changes in surgical strategy depending upon FFR results (in FFR-guided group only); and (3) rate of major adverse cardiac and cerebrovascular events, i.e., composite of death, myocardial infarction, stroke, and any revascularization during the follow-up period. This study is the first prospective randomized trial investigating potential clinical benefits, associated with FFR-guided surgical revascularization. info:eu-repo/semantics/publishedVersion

Background— The predictive value of fractional flow reserve (FFR) measured immediately after percutaneous coronary intervention (PCI) with drug-eluting stent placement has not been prospectively investigated. We investigated the potential of post-PCI FFR measurements to predict clinical outcome in patients from FAME 1 and 2 trials (Fractional Flow Reserve or Angiography for Multivessel Evaluation). Methods and Results— All patients of FAME 1 and FAME 2 who had post-PCI FFR measurement were included. The primary outcome was vessel-oriented composite end point at 2 years, defined as vessel-related cardiovascular death, vessel-related spontaneous myocardial infarction, and ischemia-driven target vessel revascularization. Eight hundred thirty-eight vessels in 639 patients were analyzed. Baseline FFR values did not differ between vessels with versus without vessel-oriented composite end point (0.66±0.11 versus 0.63±0.14, respectively; P =0.207). Post-PCI FFR was significantly lower in vessels with vessel-oriented composite end point (0.88±0.06 versus 0.90±0.06, respectively; P =0.019). Comparing the 2-year outcome of lower and upper tertiles of post-PCI FFR significant difference was found favoring upper tertile in terms of overall vessel-oriented composite end point (9.2% versus 3.8%, respectively; hazard ratio, 1.46; 95% confidence interval, 1.02–2.08; P =0.037) and target vessel revascularization (7.0% versus 2.4%, respectively; hazard ratio, 1.59; 95% confidence interval, 1.03–2.46; P =0.037). When adjusted to sex, hypertension, diabetes mellitus, target vessel, serial stenosis, and baseline percentage diameter stenosis, a strong trend was preserved in terms of target vessel revascularization (harzard ratio, 1.55; 95% confidence interval, 0.97–2.46; P =0.066), favoring the upper tertile. Post-PCI FFR of 0.92 was found to have the highest diagnostic accuracy; however, the positive likelihood ratio remained low ( Conclusions— A higher post-PCI FFR value is associated with a better vessel-related outcome. However, its predictive value is too low to advocate its use as a surrogate clinical end point.

The aim of this review is to highlight the role of invasive functional evaluation in patients in whom coronary artery bypass graft (CABG) is indicated, and to examine the clinical evidence available in favour of fractional flow reserve (FFR) adoption in these patients, outline appropriate use, as well as point out potential pitfalls. FFR after CABG will also be reviewed, highlighting its correct interpretation and adoption when applied to both native coronary arteries and bypass grafts. Practice European guidelines support the use of FFR to complement coronary angiography with the highest degree of recommendation (Class IA) for the assessment of coronary stenosis before undertaking myocardial revascularization when previous non-invasive functional evaluation is unavailable or not conclusive. As a result, FFR has been adopted in routine clinical practice to guide clinicians decision as to whether or not perform a revascularization. Of note, due to the increasing confidence of the interventional cardiologists, FFR guidance is also being implemented to indicate or guide CABG. This is in anticipation of supportive clear-cut evidence, since recommendations for FFR adoption were based on randomized clinical trials investigating percutaneous coronary intervention (PCI) strategies in which patients with typical indications for CABG were excluded (e.g. left main disease, valvular disease, and coronary anatomy unsuitable for PCI). Based on the critical appraisal of the literature, FFR can play an important role in risk stratification and determining management strategy of patients either before or after CABG.

Background— The fractional flow reserve (FFR) value of 0.75 has been validated against ischemic testing, whereas the FFR value of 0.80 has been widely accepted to guide clinical decision making. However, revascularization when FFR is 0.76 to 0.80, within the so-called gray zone, is still debatable. Methods and Results— From February 1997 to June 2013, all patients with single-segment disease and an FFR value within the gray zone or within the 2 neighboring FFR strata (0.70–0.75 and 0.81–0.85) were included. Study end points consisted of major adverse cardiovascular events (death, myocardial infarction, and any revascularization) up to 5 years. Of 17 380 FFR measurements, 1459 patients were included. Of them, 449 patients were treated with revascularization and 1010 patients were treated with medical therapy. In the gray zone, the major adverse cardiovascular events rate was similar (37 [13.9%] versus 21 [11.2%], respectively; P =0.3) between medical therapy and revascularization, whereas a strong trend toward a higher rate of death or myocardial infarction (25 [9.4] versus 9 [4.8], P =0.06) and overall death (20 [7.5] versus 6 [3.2], P =0.059) was observed in the medical therapy group. Among medical therapy patients, a significant step-up increase in major adverse cardiovascular events rate was observed across the 3 FFR strata, especially with proximal lesion location. In revascularization patients, the major adverse cardiovascular events rate was not different across the 3 FFR strata. Conclusions— FFR in and around the gray zone bears a major prognostic value, especially in proximal lesions. These data confirm that FFR≤0.80 is valid to guide clinical decision making.

Fractional flow reserve (FFR) has never been investigated in patients with aortic stenosis (AS). From 2002 to 2010, we identified 106 patients with AS and coronary artery disease with at least one intermediate lesion treated according to FFR guidance. We matched 212 contemporary control patients with AS in which revascularization was decided on angiography only. More patients in the FFR-guided group underwent percutaneous coronary intervention (24% vs 13%; p = 0.019), whereas there was a trend toward less coronary artery bypass grafting (CABG) performed. After FFR, the number of diseased vessels was downgraded within the FFR-guided group (from 1.85 ± 0.97 to 1.48 ± 1; p