Quantitative flow ratio versus fractional flow reserve for Heart Team decision-making in multivessel disease: the randomised, multicentre DECISION QFR trial.

BACKGROUND: Vessel-level physiological data derived from pressure wire measurements are one of the important determinant factors in the optimal revascularisation strategy for patients with multivessel disease (MVD). However, these may result in complications and a prolonged procedure time. AIMS: The feasibility of using the quantitative flow ratio (QFR), an angiography-derived fractional flow reserve (FFR), in Heart Team discussions to determine the optimal revascularisation strategy for patients with MVD was investigated. METHODS: Two Heart Teams were randomly assigned either QFR- or FFR-based data of the included patients. They then discussed the optimal revascularisation mode (percutaneous coronary intervention [PCI] or coronary artery bypass grafting [CABG]) for each patient and made treatment recommendations. The primary endpoint of the trial was the level of agreement between the treatment recommendations of both teams as assessed using Cohen's kappa. RESULTS: The trial included 248 patients with MVD from 10 study sites. Cohen's kappa in the recommended revascularisation modes between the QFR and FFR approaches was 0.73 [95% confidence interval {CI} : 0.62-0.83]. As for the revascularisation planning, agreements in the target vessels for PCI and CABG were substantial for both revascularisation modes (Cohen's kappa=0.72 [95% CI: 0.66-0.78] and 0.72 [95% CI: 0.66-0.78], respectively). The team assigned to the QFR approach provided consistent recommended revascularisation modes even after being made aware of the FFR data (Cohen's kappa=0.95 [95% CI:0.90-1.00]). CONCLUSIONS: QFR provided feasible physiological data in Heart Team discussions to determine the optimal revascularisation strategy for MVD. The QFR and FFR approaches agreed substantially in terms of treatment recommendations.

Consensus document on the clinical application of invasive functional coronary angiography from the Japanese Association of Cardiovascular Intervention and Therapeutics.

Invasive functional coronary angiography (FCA), an angiography-derived physiological index of the functional significance of coronary obstruction, is a novel physiological assessment tool for coronary obstruction that does not require the utilization of a pressure wire. This technology enables operators to rapidly evaluate the functional relevance of coronary stenoses during and even after angiography while reducing the burden of cost and complication risks related to the pressure wire. FCA can be used for treatment decision-making for revascularization, strategy planning for percutaneous coronary intervention, and procedure optimization. Currently, various software-computing FCAs are available worldwide, with unique features in their computation algorithms and functions. With the emerging application of this novel technology in various clinical scenarios, the Japanese Association of Cardiovascular Intervention and Therapeutics task force was created to outline expert consensus on the clinical use of FCA. This consensus document advocates optimal clinical applications of FCA according to currently available evidence while summarizing the concept, history, limitations, and future perspectives of FCA along with globally available software.

Physiology-guided PCI versus CABG for left main coronary artery disease: insights from the DEFINE-LM registry.

There have been no studies comparing clinical outcomes of physiology-guided revascularization in patients with unprotected left main coronary disease (ULMD) between percutaneous coronary intervention (PCI) vs. coronary artery bypass grafting (CABG). The aim of this study was to assess the long-term clinical outcomes between PCI and CABG of patients with physiologically significant ULMD. From an international multicenter registry of ULMD patients interrogated with instantaneous wave-free ratio (iFR), we analyzed data from 151 patients (85 PCI vs. 66 CABG) who underwent revascularization according to the cutoff value of iFR ≤ 0.89. Propensity score matching was employed to adjust for baseline clinical characteristics. The primary endpoint was a composite of all-cause death, non-fatal myocardial infarction, and ischemia-driven target lesion revascularization. The secondary endpoints were the individual components of the primary endpoint. Mean age was 66.6 (± 9.2) years, 79.2% male. Mean SYNTAX score was 22.6 (± 8.4) and median iFR was 0.83 (IQR 0.74-0.87). After performing propensity score matching analysis, 48 patients treated with CABG were matched to those who underwent PCI. At a median follow-up period of 2.8 years, the primary endpoint occurred in 8.3% in PCI group and 20.8% in CABG group, respectively (HR 3.80; 95% CI 1.04-13.9; p = 0.043). There was no difference in each component of the primary event (p > 0.05 for all). Within the present study, iFR-guided PCI was associated with lower cardiovascular events rate in patients with ULMD and intermediate SYNTAX score, as compared to CABG. State-of-the-art PCI vs. CABG for ULMD. Study design and primary endpoint in patients with physiologically significant ULMD. MACE was defined as the composite of all-cause death, non-fatal myocardial infarction, and target lesion revascularization. The blue line denotes the PCI arm, and the red line denotes the CABG arm. PCI was associated with significantly lower risk of MACE than CABG. CABG: coronary artery bypass grafting; iFR: instantaneous wave-free ratio; MACE: major adverse cardiovascular events; PCI: percutaneous coronary intervention; ULMD: unprotected left main coronary artery disease.

Angiography-derived functional assessment of left main coronary stenoses.

OBJECTIVES: We aimed to evaluate the diagnostic accuracy of quantitative flow ratio (QFR) in left main (LM) coronary stenoses, using Fractional Flow Reserve (FFR) as reference. BACKGROUND: QFR has demonstrated a high accuracy in determining the functional relevance of coronary stenoses in non-LM. However, there is an important paucity of data regarding its diagnostic value in the specific anatomical subset of LM disease. METHODS: This is a retrospective, observational, multicenter, international, and blinded study including patients with LM stenoses. Cases with significant ostial LM disease were excluded. QFR was calculated from conventional angiograms at blinded fashion with respect to FFR. RESULTS: Sixty-seven patients with LM stenoses were analyzed. Overall, LM had intermediate severity, both from angiographic (diameter stenosis [%DS] 43.8 ± 11.1%) and functional perspective (FFR 0.756 ± 0.105). Mean QFR was 0.733 ± 0.159. Correlation between QFR and FFR was moderate (r = 0.590). Positive and negative predictive value, sensitivity and specificity were 85.4%, 64%, 85.4%, and 69.6% respectively. Classification agreement of QFR and FFR in terms of functional stenosis severity was 78.1%. Area under the receiver operating characteristics of QFR using FFR as reference was 0.82 [95% confidence interval [CI], 0.71-0.93], and significantly better than angiographic evaluation including %DS (area under the receiver-operating characteristic curve [AUC] 0.45 [95% CI, 0.32-0.58], p < 0.001) and minimum lumen diameter (AUC 0.60 [95% CI, 0.47-0.74], p < 0.001). CONCLUSIONS: Compared with FFR, QFR has acceptable diagnostic performance in determining the functional relevance of LM stenosis, being better than conventional angiographic assessment. Nonetheless, caution should be taken when applying functional angiography techniques for the assessment of LM stenosis given its particular anatomical characteristics.

Diagnostic Accuracy of Artificial Intelligence-Based Angiography-Derived Fractional Flow Reserve Using Pressure Wire-Based Fractional Flow Reserve as a Reference.

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

Fractional Flow Reserve Versus Instantaneous Wave-Free Ratio in Assessment of Lesion Hemodynamic Significance and Explanation of their Discrepancies. International, Multicenter and Prospective Trial: The FiGARO Study.

Background The FiGARO (FFR versus iFR in Assessment of Hemodynamic Lesion Significance, and an Explanation of Their Discrepancies) trial is a prospective registry searching for predictors of fractional flow reserve/instantaneous wave-free ratio (FFR/iFR) discrepancy. Methods and Results FFR/iFR were analyzed using a Verrata wire, and coronary flow reserve was analyzed using a Combomap machine (both Philips-Volcano). The risk polymorphisms for endothelial nitric oxide synthase and for heme oxygenase-1 were analyzed. In total, 1884 FFR/iFR measurements from 1564 patients were included. The FFR/iFR discrepancy occurred in 393 measurements (20.9%): FFRp (positive)/iFRn (negative) type (264 lesions, 14.0%) and FFRn/iFRp (129 lesions, 6.8%) type. Coronary flow reserve was measured in 343 lesions, correlating better with iFR (R=0.56, P<0.0001) than FFR (R=0.36, P<0.0001). The coronary flow reserve value in FFRp/iFRn lesions (2.24±0.7) was significantly higher compared with both FFRp/iFRp (1.39±0.36), and FFRn/iFRn lesions (1.8±0.64, P<0.0001). Multivariable logistic regression analysis confirmed (1) sex, age, and lesion location in the right coronary artery as predictors for FFRp/iFRn discrepancy; and (2) hemoglobin level, smoking, and renal insufficiency as predictors for FFRn/iFRp discrepancy. The FFRn/iFRp type of discrepancy was significantly more frequent in patients with both risk types of polymorphisms (endothelial nitric oxide synthaser+heme oxygenase-1r): 8 patients (24.2%) compared with FFRp/iFRn type of discrepancy: 2 patients (5.9%), P=0.03. Conclusions Predictors for FFRp/iFRn discrepancy were sex, age, and location in the right coronary artery. Predictors for FFRn/iFRp were hemoglobin level, smoking, and renal insufficiency. The risk type of polymorphism in endothelial nitric oxide synthase and heme oxygenase-1 genes was more frequently found in patients with FFRn/iFRp type of discrepancy. Registration URL: https://clinicaltrials.gov; Unique identifier: NCT03033810.

Heart Team risk assessment with angiography-derived fractional flow reserve determining the optimal revascularization strategy in patients with multivessel disease: Trial design and rationale for the DECISION QFR randomized trial.

In patients with multivessel disease (MVD), functional information on lesions improves the prognostic capability of the SYNTAX score. Quantitative flow ratio (QFR®) is an angiography-derived fractional flow reserve (FFR) that does not require a pressure wire or pharmacological hyperemia. We aimed to investigate the feasibility of QFR-based patient information in Heart Teams' discussions to determine the optimal revascularization strategy for patients with MVD. We hypothesized that there is an acceptable agreement between treatment recommendations based on the QFR approach and recommendation based on the FFR approach. The DECISION QFR study is a prospective, multicenter, randomized controlled trial that will include patients with MVD who require revascularization. Two Heart Teams comprising cardiologists and cardiac surgeons will be randomized to select a revascularization strategy (percutaneous coronary intervention or coronary artery bypass graft) according to patient information either based on QFR or on FFR. All 260 patients will be assessed by both teams with reference to the anatomical and functional SYNTAX score/SYNTAX score II 2020 derived from the allocated physiological index (QFR or FFR). The primary endpoint of the trial is the level of agreement between the treatment recommendations of both teams, assessed using Cohen's κ. As of March 2022, the patient enrollment has been completed and 230 patients have been discussed in both Heart Teams. The current trial will indicate the usefulness of QFR, which enables a wireless multivessel physiological interrogation, in the discussions of Heart Teams to determine the optimal revascularization strategy for MVD.

Stress Myocardial Perfusion Imaging Interpretation From the Viewpoint of Fractional Flow Reserve.

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

Accuracy of Intravascular Ultrasound-Based Fractional Flow Reserve in Identifying Hemodynamic Significance of Coronary Stenosis.

BACKGROUND: Ultrasonic flow ratio (UFR) is a novel method for fast computation of fractional flow reserve (FFR) from intravascular ultrasound images. The objective of this study is to evaluate the diagnostic performance of UFR using wire-based FFR as the reference. METHODS: Post hoc computation of UFR was performed in consecutive patients with both intravascular ultrasound and FFR measurement in a core lab while the analysts were blinded to FFR. RESULTS: A total of 167 paired comparisons between UFR and FFR from 94 patients were obtained. Median FFR was 0.80 (interquartile range, 0.68-0.89) and 50.3% had a FFR≤0.80. Median UFR was 0.81 (interquartile range, 0.69-0.91), and UFR showed strong correlation with FFR (r=0.87; P<0.001). The area under the curve was higher for UFR than intravascular ultrasound-derived minimal lumen area (0.97 versus 0.89, P<0.001). The diagnostic accuracy, sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, and negative likelihood ratio for UFR to identify FFR≤0.80 was 92% (95% CI, 87-96), 91% (95% CI, 82-96), 96% (95% CI, 90-99), 96% (95% CI, 89-99), 91% (95% CI, 93-96), 25.0 (95% CI, 8.2-76.2), and 0.10 (95% CI, 0.05-0.20), respectively. The agreement between UFR and FFR was independent of lesion locations (P=0.48), prior myocardial infarction (P=0.29), and imaging catheters (P=0.22). Intraobserver and interobserver variability of UFR analysis was 0.00±0.03 and 0.01±0.03, respectively. Median UFR analysis time was 102 (interquartile range, 87-122) seconds. CONCLUSIONS: UFR had a strong correlation and good agreement with FFR. The fast computational time and excellent analysis reproducibility of UFR bears the potential of a wider adoption of integration of coronary imaging and physiology in the catheterization laboratory.

Determination of the Optimal Measurement Point for Fractional Flow Reserve Derived From CTA Using Pressure Wire Assessment as Reference.

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

In vivo validation of resting full-cycle ratio and diastolic pressure ratio: simultaneous measurement with instantaneous wave-free ratio.

The diastolic pressure ratio (dPR) and resting full-cycle ratio (RFR) are considered to be almost identical to the instantaneous wave-free ratio (iFR) in the retrospective analysis of pooled data. The aim of this study was to investigate the direct comparison of iFR and these new resting indexes in real world practice. Two pressure wires were inserted and placed in the distal part of the same coronary artery. The measurement of the iFR and the other resting indexes was performed simultaneously. A total of 54 lesions from 23 patients were subject to physiological study. In 49 lesions, iFR and other resting indexes were also measured in hyperemic conditions. The general correlation between iFR and other resting indexes was excellent in both resting and hyperemic conditions (r2 = 0.99; mean difference - 0.001 ± 0.021; p < 0.001; and r2 = 0.99; mean difference - 0.012 ± 0.025; p < 0.001, respectively). This correlation was maintained in various subgroup analyses. A diagnostic change between iFR and other resting indexes occurred in three cases (3%) when a fixed cut-off point (≤ 0.89) was applied. There was no diagnostic change when a hybrid zone (0.86 ≤ iFR ≤ 0.93) was considered. The new resting indexes and iFR showed very high correlation in real world practice. A diagnostic change only occurred in three cases (3%) when a fixed cut-off point (≤ 0.89) was applied.

Comparisons of Nonhyperemic Pressure Ratios: Predicting Functional Results of Coronary Revascularization Using Longitudinal Vessel Interrogation.

OBJECTIVES: The aim of this study was to investigate the accuracy of pre-percutaneous coronary intervention (PCI) predicted nonhyperemic pressure ratios (NHPRs) with actual post-PCI NHPRs and to assess the efficacy of PCI strategy using pre-PCI NHPR pullback. BACKGROUND: Predicting the functional results of PCI is feasible using pre-PCI longitudinal vessel interrogation with the instantaneous wave-free ratio (iFR), a pressure-based, adenosine-free NHPR. However, the reliability of novel NHPRs (resting full-cycle ratio [RFR] and diastolic pressure ratio [dPR]) for this purpose remains uncertain. METHODS: In this prospective, multicenter, randomized controlled trial, vessels were randomly assigned to receive pre-PCI iFR, RFR, or dPR pullback (50 vessels each). The pre-PCI predicted NHPRs were compared with actual NHPRs after contemporary PCI using intravascular imaging. The number and the total length of treated lesions were compared between NHPR pullback-guided and angiography-guided strategies. RESULTS: The predicted NHPRs were strongly correlated with actual NHPRs: iFR, r = 0.83 (95% confidence interval: 0.72 to 0.90; p < 0.001); RFR, r = 0.84 (95% confidence interval: 0.73 to 0.91; p < 0.001), and dPR, r = 0.84 (95% confidence interval: 0.73 to 0.91; p < 0.001). The number and the total length of treated lesions were lower with the NHPR pullback strategy than with the angiography-guided strategy, leading to physiological improvement. CONCLUSIONS: Predicting functional PCI results on the basis of pre-procedural RFR and dPR pullbacks yields similar results to iFR. Compared with an angiography-guided strategy, a pullback-guided PCI strategy with any of the 3 NHPRs reduced the number and the total length of treated lesions. (Study to Examine Correlation Between Predictive Value and Post PCI Value of iFR, RFR and dPR; UMIN000033534).

Difference in functional assessment of individual stenosis severity in serial coronary lesions between resting and hyperemic pressure-wire pullback: Insights from the GIFT registry.

BACKGROUND: Identifying the individual hemodynamic significance of tandem coronary artery lesions can be complicated by the crosstalk phenomenon which occurs between serial stenoses under hyperemic conditions. Physiological assessments performed under resting conditions are considered to be, theoretically, less affected by the hemodynamic interaction between serial coronary stenoses. The purpose of this study was to assess whether pressure-wire (PW) pullback measurements at rest and during hyperemia provided different information as to which stenosis appeared to be most functionally significant. METHODS: In consecutive patients with angiographically discrete serial lesions, physiological lesion predominance (i.e. proximal or distal) was defined according to the pressure gradient along the vessels on PW-pullback trace. We used instantaneous wave-free ratio (iFR) based assessment as the reference standard and compared fractional flow reserve (FFR) based and hyperemic-iFR based lesion predominance. RESULTS: Eighty-eight vessels (70 patients, mean age 70.3 ± 9.4 years, 80% male) were included in this study. Median iFR, FFR and hyperemic-iFR were 0.85 (interquartile range [IQR]: 0.74 to 0.91), 0.73 (IQR: 0.65 to 0.80) and 0.60 (IQR: 0.49 to 0.71), respectively. When judged against iFR-pullback based physiological assessment, lesion predominance changed in 22.7% (20/88) in FFR and in 20.5% (18/88) in hyperemic-iFR, respectively. There was no statistical difference between FFR and hyperemic-iFR for the impact on these changes (p = 0.77). CONCLUSIONS: In serial coronary lesions, hyperemic PW-pullback disagreed with resting PW-pullback on the lesion-specific identification of ischemia in approximately 20% of cases, either in whole cardiac cycle or in wave-free period.

Per-Vessel Level Analysis of Fractional Flow Reserve and Instantaneous Wave-Free Ratio Discordance　- Insights From the AJIP Registry.

BACKGROUND: The per-vessel level impact of physiological pattern of disease on the discordance between fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) has not been clarified.Methods and Results:Using the AJIP registry, vessels with FFR/iFR discordance (133/671 [19.8%]) were analyzed. In the left anterior descending artery (LAD), physiologically diffuse disease, as assessed by pressure-wire pullback, was associated with FFR-/iFR+ (83.3% [40/48]), while physiologically focal disease was associated with FFR+/iFR- (57.4% [31/54]), significantly (P<0.0001). These differences were not significant in non-LAD (P=0.17). CONCLUSIONS: The impact of physiological pattern of disease on FFR/iFR discordance is more pronounced in the LAD.

Endothelial dysfunction assessed by digital tonometry and discrepancy between fraction flow reserve and instantaneous wave free ratio.

Background: We tested whether the level of endothelial dysfunction assessed by digital tonometry, and expressed as reactive hyperemia index (RHI), is related to occurrences of a discrepancy between fractional flow reserve (FFR) and the instantaneous wave free ratio (iFR) (ClinicalTrials.gov identifier: NCT03033810).Methods: We examined patients with coronary stenosis in the range of 40-70%, assessed by both FFR and iFR (system Philips-Volcano) for stable angina. We included consecutive patients with FFR and iFR in one native coronary artery, and who had had no previous intervention.Results: We included 138 patients. Out of those, 24 patients (17.4%) had a negative FFR (with an FFR value >0.8) and positive iFR (with a iFR value ≤0.89) - designated the FFRn/iFRp discrepancy group, and 22 patients (15.9%) had a positive FFR (≤0.8) and negative iFR (>0.89) - designated the FFRp/iFRn discrepancy. RHI was higher in the discrepancy groups compared the group without discrepancy (1.73 ± 0.79 vs. 1.48 ± 0.50, p = 0.025). However, this finding was not confirmed in multivariant logistic regression analyses. Patients with any type of discrepancy differed from the agreement group by having a higher occurrence of diabetes mellitus [9 patients (21.4%) vs. 36 patients (39.6%), p = 0.029], active smoking (23 patients or 54.8% vs. 26 patients or 28.6%, p = 0.003) and lower use of calcium channel blockers (9 patients, 21.4%, vs. 43 patients, 46.7%, p = 0.004).Conclusion: The presence of endothelial dysfunction can be associated with a discrepancy in FFR/iFR. However, RHI correlated with risk factors of atherosclerosis, not with FFR or iFR.

QFR Versus FFR Derived From Computed Tomography for Functional Assessment of Coronary Artery Stenosis.

OBJECTIVES: The aim of this study was to compare diagnostic performance between quantitative flow ratio (QFR) derived from coronary angiography and fractional flow reserve derived from computed tomography (FFRCT) using fractional flow reserve (FFR) as the reference standard. BACKGROUND: QFR and FFRCT are recently developed, less invasive techniques for functional assessment of coronary artery disease. METHODS: QFR, FFRCT, and FFR were measured in 152 patients (233 vessels) with stable coronary artery disease. RESULTS: QFR was highly correlated with FFR (r = 0.78; p < 0.001), whereas FFRCT was moderately correlated with FFR (r = 0.63; p < 0.001). Both QFR and FFRCT showed moderately good agreement with FFR, presenting small values of mean difference but large values of root mean squared deviation (FFR-QFR, 0.02 ± 0.09; FFR-FFRCT, 0.03 ± 0.11). The sensitivity, specificity, positive predictive value, and negative predictive value of QFR ≤0.80 for predicting FFR ≤0.80 were 90%, 82%, 81%, and 90%, respectively. Those of FFRCT ≤0.80 for predicting FFR ≤0.80 were 82%, 70%, 70%, and 82%, respectively. The diagnostic accuracy of QFR ≤0.80 for predicting FFR ≤0.80 was 85% (95% confidence interval [CI]: 81% to 89%), whereas that of FFRCT ≤0.80 for predicting FFR ≤0.80 was 76% (95% CI: 70% to 80%). CONCLUSIONS: QFR and FFRCT showed significant correlation with FFR. Mismatches between QFR and FFR and between FFRCT and FFR were frequent.