Quantitative Flow Ratio Values Research Articles

Preoperative Quantitative Flow Ratio, Intraoperative Transit Time Flow Measurement Parameters, and Their Predictive Value for Short-Term Graft Failure After Coronary Artery Bypass Grafting.

Studies on the relationship between the preoperative quantitative flow ratio (QFR) and parameters of intraoperative transit time flow measurement (TTFM) are extremely rare. In addition, the predictive value of QFR and TTFM parameters for early internal mammary artery (IMA) failure after coronary artery bypass grafting still needs to be validated.Methods and Results: We retrospectively collected data from 510 patients who underwent in situ IMA grafting to the left anterior descending (LAD) artery at Fuwai Hospital. Spearman correlation coefficients between preoperative QFR of the LAD artery and intraoperative TTFM parameters of the IMA were -0.13 (P=0.004) for mean graft flow (Qm) and 0.14 (P=0.002) for the pulsatility index (PI). QFR and TTFM exhibited similar and good predictive value for early IMA failure (5.7% at 1 year), and they were better than percentage diameter stenosis (area under the curve 0.749 for QFR, 0.733 for Qm, 0.688 for PI, and 0.524 for percentage diameter stenosis). The optimal cut-off value of QFR was 0.765. Both univariate and multivariable regression analyses revealed that QFR >0.765, Qm ≤15 mL/min, and PI >3.0 independently contributed to early IMA failure. There were statistically significant correlations between preoperative QFR of the LAD artery and intraoperative TTFM parameters (Qm, PI) of the IMA. Preoperative QFR and intraoperative Qm and PI exhibited excellent predictive value for early IMA failure.

QFR for the Revascularization of Nonculprit Vessels in MI Patients: Insights From the FIRE Trial.

The role of quantitative flow ratio (QFR) in the treatment of nonculprit vessels of patients with myocardial infarction (MI) is a topic of ongoing discussion. This study aimed to investigate the predictive capability of QFR for adverse events and its noninferiority compared to wire-based functional assessment in nonculprit vessels of MI patients. The FIRE (Functional Assessment in Elderly MI Patients With Multivessel Disease) trial randomized 1,445 older MI patients to culprit-only (n=725) or physiology-guided complete revascularization (n=720). In the culprit-only arm, angiographic projections of nonculprit vessels were prospectively collected, centrally reviewed for QFR computation, and associated with endpoints. In the complete revascularization arm, endpoints were compared between nonculprit vessels investigated with QFR or wire-based functional assessment. The primary endpoint was the vessel-oriented composite endpoint (VOCE) at 1 year. QFR was measured on 903 nonculprit vessels from 685 patients in the culprit-only arm. Overall, 366 (40.5%) nonculprit vessels showed a QFR value≤0.80, with a significantly higher incidence of VOCEs (22.1% vs 7.1%; P< 0.001). QFR≤0.80 emerged as an independent predictor of VOCEs (HR: 2.79; 95%CI: 1.64-4.75). In the complete arm, QFR was used in 320 (35.2%) nonculprit vessels to guide revascularization. When compared with propensity-matched nonculprit vessels in which treatment was guided by wire-based functional assessment, no significant difference was observed (HR:0.57; 95%CI: 0.28-1.15) in VOCEs. This prespecified subanalysis of the FIRE trial provides evidence supporting the safety and efficacy of QFR-guided interventions for the treatment of nonculprit vessels in MI patients. (Functional Assessment in Elderly MI Patients With Multivessel Disease [FIRE]; NCT03772743).

Clinical Value of the Quantitative Flow Ratio to Predict Long-term Target Vessel Failure in Patients with In-stent Restenosis after Drug-coated Balloon Angioplasty.

The study sought to investigate the clinical predictive value of quantitative flow ratio (QFR) for the long-term target vessel failure (TVF) outcome in patients with in-stent restenosis (ISR) by using drug-coated balloon (DCB) treatment after a long-term follow-up. This was a retrospective study. A total of 186 patients who underwent DCB angioplasty for ISR in two hospitals from March 2014 to September 2019 were enrolled. The QFR of the entire target vessel was measured offline. The primary endpoint was TVF, including target vessel-cardiac death (TV-CD), target vessel-myocardial infarction (TV-MI), and clinically driven-target vessel revascularization (CD-TVR). The follow-up time was 3.09±1.53 years, and 50 patients had TVF. The QFR immediately after percutaneous coronary intervention (PCI) was significantly lower in the TVF group than in the no-TVF group. Multivariable Cox regression analysis indicated that the QFR immediately after PCI was an excellent predictor for TVF after the long-term follow-up [hazard ratio (HR): 5.15×10-5 (6.13×10-8-0.043); P<0.01]. Receiver-operating characteristic (ROC) curve analysis demonstrated that the optimal cut-off value of the QFR immediately after PCI for predicting the long-term TVF was 0.925 (area under the curve: 0.886, 95% confidence interval: 0.834-0.938; sensitivity: 83.40%, specificity: 88.00; P<0.01). In addition, QFR≤0.925 post-PCI was strongly correlated with the TVF, including TV-MI and CD-TVR (P<0.01). The QFR immediately after PCI showed a high predictive value of TVF after a long-term follow-up in ISR patients who underwent DCB angioplasty. A lower QFR immediately after PCI was associated with a worse TVF outcome.

VALIDATION OF QUANTITATIVE FLOW RATIO DERIVED VIRTUAL ANGIOPLASTY WITH POST–ANGIOPLASTY FRACTIONAL FLOW RESERVE. THE QIMERA–I STUDY

Abstract Backgroud Quantitative flow ratio (QFR) virtual angioplasty with pre–PCI residual QFR showed better results compared with angiographic approach to assess post–PCI functional results. However correlation with pre–PCI residual QFR and post–PCI fractional flow reserve (FFR) is lacking. Methods Multicenter prospective study including consecutive patientswith angiographically 50–90% coronary lesions and positive QFR result. All patients were evaluated with QFR, hyperemic and non–hyperemic pressure ratios (NHPR) before and after the index PCI. Pre–PCI residual QFR (virtual angioplasty) was calculated and compared with post–PCI fractional flow reserve (FFR), QFR and NHPR. Results A total of 84 patients with 92 treated coronary lesions were included, with a mean age of 65.5±10.9 years and 59% of single vessel lesion being the left anterior descending artery in 69%. The mean vessel diameter was 2.82±0.41 mm. Procedural success was achieved in all cases, with a mean number of implanted stents of 1.17±0.46. Baseline QFR value was 0.69 ± 0.12 and baseline FFR and NHPR were 0.73 + 0.08 and 0.82 + 0.11, respectively. Mean post–PCI FFR increased to 0.87 ±0.05 whereas residual QFR had been estimated as 0.95 ± 0.05 showing poor correlation with post–PCI FFR (0.163; 95%CI:0.078–0.386) and a low diagnostic accuracy (30.9%, 95%CI:20–43%). Conclusions In this analysis, the results of QFR–based virtual angioplasty did not seem to accurately correlate with post–PCI FFR.

Contrasting the relationship of serum uric acid/albumin ratio on quantitative flow ratio with other multiple composite parameters in patients with suspected coronary artery disease

ObjectiveThe aim of this study was to investigate the association between quantitative coronary flow reserve (CFR) and the blood uric acid/albumin ratio, as well as multiple clinical parameters, in order to assess the severity of coronary artery functional stenosis.MethodsThis retrospective cross-sectional study included 257 suspected coronary artery disease patients who underwent coronary angiography (CAG) and quantitative flow ratio (QFR) examinations in the Department of Cardiovascular Medicine at the First Affiliated Hospital of Yangtze University in Jingzhou City, China, between September 2022 and March 2023. The study subjects were divided into two groups based on their QFR values: QFR ≤ 0.80 group and QFR > 0.80 group. Correlation of uric acid-to-albumin ratio (UAR), high-density lipoprotein ratio (MHR), systemic immune-inflammation index (SII), Systemic Inflammation Response Index (SIRI), and Aggregate Index of Systemic Inflammation (AISI) with coronary artery QFR was analyzed using univariate and multivariate logistic regression models, considering them as both continuous and binary variables.ResultsThe QFR ≤ 0.80 group consisted of 83 patients, while the QFR > 0.80 group included 174 patients. Significant differences were observed between the QFR ≤ 0.80 and QFR > 0.80 groups in the following parameters: UAR (9.19 ± 2.47 vs 7.61 ± 1.91; p < 0.001), MHR (0.46 ± 0.19 vs 0.37 ± 0.16, p < 0.001), SII (674.98 ± 332.30 vs 571.43 ± 255.82; p = 0.006), SIRI (1.53 ± 0.83 vs 1.29 ± 1.10; p = 0.047), and AISI (340.22 ± 242.10 vs 243.97 ± 151.97; p < 0.001). ROC curve analysis revealed an area under the curve of 0.701 (CI: 0.633–0.770; p < 0.001) for UAR. In the univariate analysis, when treated as binary variables, high levels of UAR, MHR, SII, SIRI, and AISI were found to be significantly associated with the risk of QFR ≤ 0.80 (all P < 0.05). However, in the multivariate regression analysis, only high levels of UAR and AISI remained significantly associated with QFR ≤ 0.80 (all P < 0.05). When treated as continuous variables, the univariate analysis indicated that UAR (OR: 1.412, CI: 1.231–1.620, p < 0.001), e^MHR (OR: 1.394, CI: 1.151–1.687, p < 0.001), lnSII (OR: 1.001, CI: 1.000–1.002, p = 0.008), and lnAISI (OR: 2.695, CI: 1.539–4.719, p = 0.001) were significantly associated with QFR ≤ 0.80. In the multivariate analysis, UAR (OR: 1.373, CI: 1.187–1.587, p < 0.001) and AISI (OR: 2.217, CI: 1.309–3.757, p < 0.001) remained significantly associated with QFR ≤ 0.80.ConclusionsThe results of this study indicate a significant association between UAR and AISI with QFR ≤ 0.80, suggesting its potential role in predicting the extent of functional coronary artery stenosis in patients with CAD. Additionally, AIRI, identified as an inflammatory marker in the complete blood count, was found to exert influence on the severity of coronary artery physiology.

The value of quantitative flow ratio in the hemodynamic evaluation of myocardial bridge

Objective: To explore the application value of quantitative flow ratio (QFR) in the hemodynamic evaluation of myocardial bridge and to preliminarily evaluate the correlation and related influencing factors between deformation quantitative flow ratio (D-QFR) and QFR. Methods: This is a cross-sectional study. Patients with CAG-confirmed simple myocardial bridge of the middle anterior descending coronary artery from June 2012 to June 2022 at the Air Force Medical Center were retrospectively included in this study. Systolic stenosis of mural coronary arteries (MCA) and myocardial bridge length were measured using quantitative coronary angiography. The patients were divided into mild stenosis group (<50% systolic stenosis) and moderate-to-severe stenosis group (≥50% systolic stenosis) according to the Nobel grading criteria. At different time periods (systolic and diastolic), the QFR values were measured at 3 locations (1 to 2 cm before the MCA entrance, the middle segment of the MCA, and 1 to 2 cm after the MCA exit), denoted as QFRa, QFRb, and QFRc, respectively, and the D-QFR values, incorporating vessel deformation information, were recorded. The MCA distal QFR≤0.8 in either stage was defined as an abnormal QFR value. QFR values were compared between the two groups at different locations and within each group. Factors associated with abnormal QFR values were analysed using multifactorial logistic regression. Spearman rank correlation analysis was used to examine the correlation between D-QFR values and systolic and diastolic QFR values.Multiple linear regression was used to analyse the factors associated with D-QFR. Results: A total of 83 patients were enrolled, including 58 males, aged (57.1±13.1) years. There were 48 cases in the mild stenosis group and 35 cases in the moderate-to-severe stenosis group, and the differences in systolic and diastolic QFRb and QFRc values between the two groups were statistically significant (all P<0.05). Within-group comparisons showed the values of QFRb and QFRc in the systolic phase were lower than those in the diastolic phase; QFRb and QFRc were both lower than QFRa during the same period (all P<0.05). Multifactorial logistic regression analysis showed that MCA systolic stenosis (OR=1.225, 95%CI 1.093-1.372, P<0.001) was an influential factor for abnormal QFR. D-QFR values were positively correlated with both systolic and diastolic QFR values (correlation coefficients were 0.849 and 0.675, respectively, both P<0.01). Multiple linear regression analysis showed that D-QFR values were negatively correlated with age (β=-0.208, P=0.029), systolic stenosis (β=-0.500, P<0.001), and myocardial bridge length (β=-0.211, P=0.036). Conclusions: The QFR values in middle and distal of myocardial bridge decrease. The systolic stenosis rate of myocardial bridge is an important factor affecting QFR value. D-QFR is positively correlated with both systolic and diastolic QFR values. Age, myocardial bridge systolic stenosis rate and length are factors influencing the D-QFR values.

Validation of Quantitative Flow Ratio-Derived Virtual Angioplasty with Post-Angioplasty Fractional Flow Reserve-The QIMERA-I Study.

Background: Quantitative flow ratio (QFR) virtual angioplasty with pre-PCI residual QFR showed better results compared with an angiographic approach to assess post-PCI functional results. However, correlation with pre-PCI residual QFR and post-PCI fractional flow reserve (FFR) is lacking. Methods: A multicenter prospective study including consecutive patients with angiographically 50-90% coronary lesions and positive QFR results. All patients were evaluated with QFR, hyperemic and non-hyperemic pressure ratios (NHPR) before and after the index PCI. Pre-PCI residual QFR (virtual angioplasty) was calculated and compared with post-PCI fractional flow reserve (FFR), QFR and NHPR. Results: A total of 84 patients with 92 treated coronary lesions were included, with a mean age of 65.5 ± 10.9 years and 59% of single vessel lesions being the left anterior descending artery in 69%. The mean vessel diameter was 2.82 ± 0.41 mm. Procedural success was achieved in all cases, with a mean number of implanted stents of 1.17 ± 0.46. The baseline QFR value was 0.69 ± 0.12 and baseline FFR and NHPR were 0.73 ± 0.08 and 0.82 ± 0.11, respectively. Mean post-PCI FFR increased to 0.87 ± 0.05 whereas residual QFR had been estimated as 0.95 ± 0.05, showing poor correlation with post-PCI FFR (0.163; 95% CI:0.078-0.386) and low diagnostic accuracy (30.9%, 95% CI:20-43%). Conclusions: In this analysis, the results of QFR-based virtual angioplasty did not seem to accurately correlate with post-PCI FFR.

Quantitative flow ratio computed from invasive coronary angiography as a predictor for cardiac allograft vasculopathy after cardiac transplant.

Cardiac allograft vasculopathy (CAV) is a significant determinant of long-term survival in heart transplant recipients. Standard CAV screening typically utilizes invasive coronary angiography (ICA). Quantitative flow ratio (QFR) is a computational method for functional testing of coronary stenosis, and may add diagnostic value to ICA in assessing CAV. Consecutive subjects who received heart transplantation and underwent two separate routine coronary angiograms between January 2013 and April 2016 were enrolled. Coronary angiograms and IVUS were performed per local protocol at 1, 2, 3 and 5years post-transplant. QFR was calculated offline. CAV was assessed semi-quantitively based on coronary angiogram results. Twenty-two patients were enrolled. Mean time from transplant to first included ICA was 2.1years. QFR in at least 1 coronary vessel was interpretable in 19/22 (86%) of initial ICA (QFR1). QFR1 correlated well with the CAV score derived from the second ICA (CAV2) with a clustering of CAV at lower QFR values. In a receiver-operating characteristic (ROC) analysis, an optimal QFR threshold of 0.88 yielded 0.94 sensitivity and 0.67 specificity (AUC of 0.79) for at least non-obstructive subsequent CAV. Initial angiographically and intravascular ultrasound derived CAV severity poorly predicted subsequent CAV severity. QFR derived from invasive coronary angiography predicts subsequent development of CAV more accurately than angiography and intravascular ultrasound. This novel method of coronary flow assessment in recipients of heart transplantation may be useful to diagnose and predict subsequent CAV development.

Does the pre-procedural pathophysiological pattern impact post-procedural hemodynamic outcomes and vessel prognosis in multivessel coronary artery disease?

Abstract Aim The pathophysiological pattern of coronary artery disease (CAD) pre-procedure may affect the physiological response to percutaneous coronary intervention (PCI). The aim of this study was to evaluate whether the pathophysiological pattern of CAD, derived from virtual pullbacks of angiography-based fractional flow reserve, impacted the immediate hemodynamic outcome post-PCI. Methods and results Among 503 consecutive patients with chronic coronary syndrome and non-ST elevated acute coronary syndrome treated at least 1 vessel in the Multivessel TALENT trial, 826 quantitative flow ratio (QFR) analysable vessels were enrolled. Pre-procedural pathophysiological patterns in CAD were characterized by the physiological distribution and local severity of coronary atherosclerosis using QFR-derived indexes acquired from pre-PCI angiograms. The physiological distribution of CAD was defined as "predominant diffuse" or "focal" according to a QFR pullback pressure gradient (PPG) index &amp;lt;0.78 and ≥0.78, respectively. Physiological local severity was assessed using QFR gradient per 1 mm (dQFR/ds), with a value ≥ 0.025/mm defining the presence of a "major gradient". The optimal post-PCI QFR value was defined as QFR ≥0.91. Among the 826 vessels, 673 vessels were analysed (excluding vessels which have total occlusions, ostial lesions, and paired QFR not analysable). Mean pre-PCI PPG index was 0.70 with a nadir in the distribution curve. As per the definition, "focal" lesions were 30% of the total analysed vessels and 88% had a "major gradient". The majority of the vessels belong to predominantly diffuse disease with a major gradient (62.7%, Figure 1). Compared to predominantly focal disease with a major gradient, predominantly diffuse disease had a higher risk of a post-PCI QFR &amp;lt;0.91 (OR 1.78, 95%CI 1.23-2.58). The scatterplot between pre-procedural PPGI and post-procedural QFR showed positive correlation (Piason’s R=0.163, p&amp;lt;0.001, Figure 2). The correlation suggested that the vessels with focal lesions more frequently achieved optimal post-PCI QFR values compared to that with diffuse lesions. In multivariable analysis, low QFR PPG index (diffuse disease) was an independent factor for predicting a post-PCI QFR&amp;lt;0.91 (per 0.1 decreases of QFR PPG index, OR:10.3, 95% CI 1.7-63.3, p=0.012). The estimated 2-year VOCE, the powered secondary endpoint of this study, estimated by the post-QFR is 5.9% in treated vessels with predominant diffuse lesion, while 4.9% in that with predominant focal lesion based on the previous substudy of SYNTAX II trial.[1] Conclusions A physiological pattern of diffuse CAD pre-procedure was an independent factor in predicting an unfavourable immediate hemodynamic outcome post-PCI. Pre-procedural PPG index can be the predictor of not only post-PCI physiological value but also vessel base prognosis.pre-PCI pathophysiological patternScatterplot and correlation

Prognosis after non-infarct related artery PCI in patients with acute myocardial infarction and multivessel disease: substudy of FRAME-AMI trial

Abstract Background Complete revascularization either angiography-guided or fractional flow reserve (FFR)-guided can improve the clinical outcomes in patients with acute myocardial infarction (AMI) and multivessel disease. However, there is concern that angiography-guided percutaneous coronary intervention (PCI) may result in unnecessary PCI of non-infarct related artery (IRA) and its long-term prognosis is still unclear. Purpose We sought to evaluate clinical outcomes after non-IRA PCI according to quantitative flow ratio (QFR). Methods We performed post-hoc QFR analysis of non-IRA lesions of AMI patients who enrolled in the FRAME-AMI trial which randomly allocated patients into either FFR-guided PCI (FFR≤0.80) or angiography-guided PCI (diameter stenosis of &amp;gt;50%) for non-IRA lesions. Patients were classified by non-IRA QFR values into the QFR≤0.80 and QFR&amp;gt;0.80 groups. The primary end point was a major adverse cardiac event (MACE), a composite of cardiac death, MI, and repeat revascularization. Results A total of 443 patients (552 lesions) were eligible for the QFR analysis. Of 209 patients in the angiography-guided PCI group, 30.0% (N=60) underwent non-IRA PCI despite having QFR&amp;gt;0.80 in non-IRA. Conversely, only 2.7% (N=4) among 209 patients in the FFR-guided PCI group had QFR&amp;gt;0.80 in non-IRA. At a median follow-up of 3.5 years (interquartile range 2.7 to 4.1 years), the rate of MACE was significantly higher among patients with non-IRA PCI despite QFR&amp;gt;0.80 than patients with deferred PCI for non-IRA lesions (12.9% vs. 3.1%; HR=4.13, 95% CI 1.10-15.57, P=0.036). Non-IRA PCI despite QFR&amp;gt;0.80 was associated with higher risk of non-IRA MACE than patients with deferred PCI for non-IRA lesions (12.9% vs. 2.1%; HR 5.44, 95% CI 1.13-26.19, P=0.035). Conclusions In AMI patients with multivessel disease, 30.0% of angiography-guided PCI resulted in unnecessary PCI for non-IRA with QFR&amp;gt;0.80, which was significantly associated with the increased risk of MACE than those with deferred PCI for non-IRA lesions.

Abstract 14323: Significance of Angio-IMR to Predict Heart Failure Post-TAVI

Background/Introduction: The number of transcatheter aortic valve implantation (TAVI) procedures is currently increasing. However, a substantial number of patients suffer from repeated heart failure (HF) after the TAVI procedure. The association between Index of Microvascular Resistance (IMR) and HF is already known, especially in HFpEF. Purpose: The aim of this study was to assess the prognostic significance of IMR for HF after TAVI. Method and Result: 120 consecutive patients who underwent coronary angiography (CAG) before undergoing TAVI in our hospital between 2018 and 2021 were included in the analysis. Quantitative Flow Ratio (QFR) analysis was performed for each coronary artery, excluding cases undergoing PCI before or after TAVI. The angiography derived IMR was then obtained from the QFR values. Finally, 65 patients were available for IMR analysis. Of these, 12 were hospitalized or underwent medical intensification for HF exacerbations after TAVI. IMR was significantly higher in patients with HF compared without HF. (73.8 (31 to 121) vs 59.7 (26 to 153), p=0.041) No other significant differences were found in age, QFR values, EF, i-EOA on echocardiography after TAVI, STS score, and BNP values before TAVI. All patients with HF were female. Conclusion: It is suggested that angio-derived IMR values before TAVI might be a useful predictor of heart failure after TAVI.

Diagnostic performance of quantitative flow ratio in non-ST elevation acute coronary syndromes in comparison to non-hyperemic pressure ratios: a prospective study.

Quantitative flow ratio (QFR) is a new angiography-based coronary physiology tool aimed to evaluate functional relevance of intermediate coronary lesions. Aim of the study is to assess diagnostic performance of QFR in patients with non-ST-elevation acute coronary syndrome (NSTE-ACS) in comparison to currently used non-hyperaemic pressure ratios (NHPRs). In this prospective, single-centre study, coronary physiology of intermediate coronary stenoses of non-culprit vessels in patients presenting with NSTE-ACS was evaluated using NHPRs (iFR, DFR or RFR). Subsequently, QFR was computed offline by a QFR analyst blinded to the NHPR results. Diagnostic performance of QFR was assessed in comparison to NHPRs as reference standard. A total of 60 vessels with intermediate coronary stenoses was investigated. The NHPRs were used as follows: RFR 38%, DFR 47% and iFR 15% of the cases. The NHPR result was positive, showing significant lesion, in 19 cases. A significant correlation was found between NHPR and QFR (r = 0.84, p < 0.001). Classification agreement of the two methods (95%) and diagnostic performance of QFR in comparison to NHPR (AUC: 0.962 [0.914-1.00]) were both high. Sensitivity, specificity, positive and negative predictive value of QFR in comparison to NHPR were 84.2%, 100%, 100% and 93.2% respectively. QFR has high diagnostic performance in detecting functionally significant lesions of non-culprit arteries in patients with NSTE-ACS and multivessel disease. Due to its high negative predictive value, it can be used to safely avoid unnecessary invasive physiological assessment of these lesions.

The Differences of Quantitative Flow Ratio in Coronary Artery Stenosis with or without Atrial Fibrillation.

Quantitative flow ratio (QFR) is a new method for the assessment of the extent of coronary artery stenosis. But it may be obscured by the cardiac remodeling and abnormal blood flow of the coronary artery when encountering atrial fibrillation (AF). The present study aimed to examine the impact of these changed structures and blood flow of coronary arteries on QFR results in AF patients. Methods and Results. We evaluated QFR in 223 patients (112 patients with AF; 111 non-AF patients served as controls) who had undergone percutaneous coronary intervention (PCI) due to severe stenoses in coronary arteries. QFR of the target coronary was determined according to the flow rate of the contrast agent. Results showed that AF patients had significantly higher QFR values than control (0.792 ± 0.118 vs. 0.685 ± 0.167, p < 0.001). We further analyzed local QFR around the stenoses (0.858 ± 0.304 vs. 0.756 ± 0.146, p=0.002), residual QFR (0.958 ± 0.055 vs. 0.929 ± 0.093, p=0.005), and index QFR (0.807 ± 0.108 vs. 0.713 ± 0.152, p < 0.001) in these two groups of patients with and without AF. Further analysis revealed that QFR in AF patients was negatively correlated with coronary flow velocity (R = -0.22, p=0.02) and area of stenosis (R = -0.70, p < 0.001) but positively correlated with the minimum lumen area (MLA) (R = 0.47, p < 0.001). Conclusion. AF patients with coronary artery stenosis have higher QFR values, which are associated with decreased blood flow velocity, smaller stenosis, and larger MLA in AF patients upon cardiac remodeling.

QFR Assessment and Prognosis After Nonculprit PCI in Patients With Acute Myocardial Infarction

BackgroundComplete revascularization using either angiography-guided or fractional flow reserve (FFR)-guided strategy can improve clinical outcomes in patients with acute myocardial infarction (AMI) and multivessel disease. However, there is concern that angiography-guided percutaneous coronary intervention (PCI) may result in un-necessary PCI of the non–infarct-related artery (non-IRA), and its long-term prognosis is still unclear. ObjectivesThis study sought to evaluate clinical outcomes after non-IRA PCI according to the quantitative flow ratio (QFR). MethodsWe performed post hoc QFR analysis of non-IRA lesions of AMI patients enrolled in the FRAME-AMI (FFR Versus Angiography-Guided Strategy for Management of AMI With Multivessel Disease) trial, which randomly allocated 562 patients into either FFR-guided PCI (FFR ≤0.80) or angiography-guided PCI (diameter stenosis >50%) for non-IRA lesions. Patients were classified by non-IRA QFR values into the QFR ≤0.80 and QFR >0.80 groups. The primary outcome was a major adverse cardiac event (MACE), a composite of cardiac death, myocardial infarction, and repeat revascularization. ResultsA total of 443 patients (552 lesions) were eligible for QFR analysis. Of 209 patients in the angiography-guided PCI group, 30.0% (n = 60) underwent non-IRA PCI despite having QFR >0.80 in the non-IRA. Conversely, only 2.7% (n = 4) among 209 patients in the FFR-guided PCI group had QFR >0.80 in the non-IRA. At a median follow-up of 3.5 years, the rate of MACEs was significantly higher among patients with non-IRA PCI despite QFR >0.80 than in patients with deferred PCI for non-IRA lesions (12.9% vs 3.1%; HR: 4.13; 95% CI: 1.10-15.57; P = 0.036). Non-IRA PCI despite QFR >0.80 was associated with a higher risk of non-IRA MACEs than patients with deferred PCI for non-IRA lesions (12.9% vs 2.1%; HR: 5.44; 95% CI: 1.13-26.19; P = 0.035). ConclusionsIn AMI patients with multivessel disease, 30.0% of angiography-guided PCI resulted in un-necessary PCI for the non-IRA with QFR >0.80, which was significantly associated with an increased risk of MACEs than in those with deferred PCI for non-IRA lesions. (FFR Versus Angiography-Guided Strategy for Management of AMI With Multivessel Disease [FRAME-AMI] ClinicalTrials.gov number; NCT02715518)

Drug-eluting stent and drug-coated balloon for the treatment of de novo diffuse coronary artery disease lesions: A retrospective case series study.

The hybrid strategy of a combination of drug-eluting stent (DES) and drug-coated balloon (DCB) is promising for the treatment of de novo diffuse coronary artery disease (CAD). To investigate the efficacy and functional results of hybrid strategy. This case series study included patients treated with a hybrid approach for de novo diffuse CAD between February 2017 and November 2021. Postprocedural quantitative flow ratio (QFR) was used to evaluate the functional results. The primary endpoint was procedural success rate. The secondary endpoints were major adverse cardiovascular events (MACE) including cardiac death, myocardial infarction (MI) (including peri-procedural MI), and target vessel revascularization. A total of 109 patients with 114 lesions were treated. DES and DCB were commonly used in larger proximal segments and smaller distal segments, respectively. The mean QFR value was 0.9 ± 0.1 and 105 patients (96.3%) had values >0.8 in all the treated vessels. Procedural success was achieved in 106 (97.2%) patients. No cases of cardiac death were reported at a median follow-up of 19 months. Spontaneous MI occurred in three (2.8%) patients and target vessel revascularization in six (5.5%) patients. Estimated 2-year rate of MACE excluding peri-procedural MI was higher in the group with lower QFR value (12.1 ± 5.7% vs. 5.6 ± 4.4%, log-rank p = .035) (cut-off value 0.9). Hybrid strategy is a promising approach for the treatment of de novo diffuse CAD. Postprocedural QFR has some implications for prognosis and may be helpful in guiding this approach.

Quantitative flow ratio-based outcomes in patients undergoing transcatheter aortic valve implantation quaestio study.

Coronary artery disease (CAD) is common in patients with aortic valve stenosis (AS) ranging from 60% to 80%. The clinical and prognostic role of coronary artery lesions in patients undergoing Transcatheter Aortic Valve Implantation (TAVI) remains unclear. The aim of the present observational study was to estimate long-term clinical outcomes by Quantitative Flow Ratio (QFR) characterization of CAD in a well-represented cohort of patients affected by severe AS treated by TAVI. A total of 439 invasive coronary angiographies of patients deemed eligible for TAVI by local Heart Teams with symptomatic severe AS were retrospectively screened for QFR analysis. The primary endpoint of the study was all-cause mortality. The secondary endpoint was a composite of cardiovascular mortality, stroke/transient ischemic attack (TIA), acute myocardial infarction (AMI), and any hospitalization after TAVI. After exclusion of patients with no follow-up data, coronary angiography not feasible for QFR analysis and previous surgical myocardial revascularization (CABG) 48/239 (20.1%) patients had a QFR value lower or equal to 0.80 (QFR + value), while the remaining 191/239 (79.9%) did not present any vessel with a QFR positive value. In the adjusted Cox regression analysis, patients with positive QFR were independently associated with an increased risk of all-casual mortality (Model 1, HR 3.47, 95% CI, 2.35-5.12; Model 2, HR 5.01, 95% CI, 3.17-7.90). In the adjusted covariate analysis, QFR+ involving LAD (37/48, 77,1%) was associated with the higher risk of the composite outcome compared to patients without any positive value of QFR or non-LAD QFR positive value (11/48, 22.9%). Pre-TAVI QFR analysis can be used for a safe, simple, wireless functional assessment of CAD. QFR permits to identify patients at high risk of cardiovascular mortality or MACE, and it could be considered by local Heart Teams.

Prognostic value of quantitative flow ratio in patients with coronary heart disease after percutaneous coronary intervention therapy: a meta-analysis.

Coronary atherosclerotic heart disease is one of the most serious health and life-threatening diseases. There is no doubt that despite the increasing number of assessment methods used clinically, the prognosis assessment is still not ideal, and newer assessment methods are needed. To investigate the predictive value of quantitative flow ratio (QFR) for adverse events (vessel-oriented composite endpoint events/target lesion failure) in patients after percutaneous coronary intervention (PCI). Eight studies involving 4,173 patients (5,688 vascular lesions) were included. These are studies on the relationship between QFR values and prognosis of adverse cardiac events after PCI. This meta-analysis was performed after quality assessment and data extraction of clinical trials data that met the inclusion criteria. Each of the eight studies described the cut-off values for the best predictive ability of post-PCI QFR and the hazard ratio (HR) between QFR values and adverse events, respectively. The pooled HR of these studies was 4.72 (95% CI: 3.29-6.75). Concurrently, lower post-PCI QFR values were associated with the occurrence of individual clinical events (cardiac death/myocardial infarction/target vessel revascularization), with relative risk values of 6.51 (95% CI: 4.96-8.53), 4.83 (95% CI: 3.08-7.57), and 4.21 (95% CI: 2.66-6.68), respectively. QFR may have great potential in the assessment of prognosis. It is necessary to measure QFR value after PCI. A lower QFR value after PCI was an important predictor for experiencing adverse events.

Predictors of long-term adverse outcomes after successful chronic total occlusion intervention: physiology or morphology?

Quantitative flow ratio (QFR) and target-vessel SYNTAX score (tvSS) are novel indices used to assess lesion physiology and morphology in percutaneous coronary intervention (PCI). Their prognostic implication after successful recanalization of coronary chronic total occlusion (CTO) is unknown. To investigate the prognostic value of QFR measured immediately after successful CTO-recanalization in predicting vessel-oriented adverse events, and to compare it with the pre-procedural morphological tvSS. QFR was measured offline after successful CTO-PCIs in a single center. We grouped the patients according to a cut-off value of post-PCI QFR (0.91). The primary outcome was target-vessel failure (TVF) at 2years. Among 470 CTO lesions performed during the study period, 324 were eligible for QFR analysis (258 with QFR ≥ 0.91 and 66 with QFR < 0.91). The mean age of the study population was 68.3 ± 10.7years. The low QFR group had a lower left ventricular ejection fraction (45.8 ± 13.9% vs. 49.8 ± 12.4%, p = 0.025) and a higher rate of atrial fibrillation (19.7% vs. 11.2%, p = 0.020). The mean tvSS was 12.8 ± 4.8, and it showed no significant difference in both groups (13.6 ± 5.1 vs. 12.6 ± 4.6, p = 0.122). Patients with low post-CTO QFR had a trend to develop more TVF at 2years (21.2% vs. 12.4%, HR 1.74; 95% CI 0.93-3.25, p = 0.086). Low post-CTO QFR failed to predict 2-year TVF (aHR 1.67; 95% CI 0.85-3.29, p = 0.136), while pre-procedural tvSS was an independent predictor for 2-year TVF (aHR 1.06; 95% CI 1.01-1.13, p = 0.030). We found a limited prognostic value of immediate physiological assessment using QFR after successful CTO intervention. Pre-procedure morphological characteristics of CTO lesions using tvSS can play a role in predicting long-term adverse events.

Quantitative flow ratio as a continuous predictor of myocardial infarction.

The quantitative flow ratio (QFR) identifies functionally ischaemic lesions that may benefit more from percutaneous coronary intervention (PCI) than from medical therapy. This study investigated the association between QFR and myocardial infarction (MI) as affected by PCI versus medical therapy. All vessels requiring measurement (reference diameter ≥2.5 mm and existence of at least one stenotic lesion with diameter stenosis of 50-90%) in the FAVOR III China (5,564 vessels) and PANDA-III trials (4,471 vessels) were screened and analysed for offline QFR. The present study reported clinical outcomes on a per-vessel level. Interaction between vessel treatment and QFR as a continuous variable was evaluated for the threshold of 2-year MI estimated by Cox proportional hazards model. Compared with medical therapy at 2 years, PCI reduced the MI risk in vessels with a QFR ≤0.80 (3.0% vs 4.6%) but increased the MI risk in vessels with a QFR>0.80 (3.6% vs 1.2%). Additionally, continuous QFR showed an inverse association with spontaneous MI (hazard ratio [HR] 0.89, 95% confidence interval [CI]: 0.79-0.99; p=0.04) that was reduced by PCI compared to medical therapy (HR 0.26, 95% CI: 0.17-0.40; p<0.0001). The interaction indicated a net benefit for PCI over medical therapy to reduce total MI beginning at QFR ≤0.64. The present study demonstrated a continuous, inverse relationship between the QFR value of a vessel and its subsequent risk for MI, and PCI, compared to medical therapy, reduced this risk beginning at a QFR value of 0.64. These novel findings provide physicians with an angiographic tool for optimising vessel selection for PCI.

Long-term prognostic value of quantitative-flow-ratio-concordant revascularization in stable coronary artery disease

ObjectivesConfirming the prognostic value of global QFR and evaluating the long-term prognosis of QFR-concordant therapy in stable coronary artery disease. BackgroundWire-based functional evaluation of coronary disease is linked to patient's prognosis. Quantitative Flow Ratio (QFR) is a newer index of computational physiology, linked to clinical outcomes and prognosis at 1 year follow-up. Long-term prognosis of QFR-concordant revascularization in stable coronary artery disease is however unknown hitherto. MethodsConsecutive patients with stable coronary disease undergoing coronary angiography were included. Centralized and blinded QFR analysis of three coronary territories was performed. Three vessel QFR (3vQFR) was defined as the sum of the basal QFR of each coronary territory. QFR-concordant revascularization was met if all significant lesions (QFR ≤ 0.80) were revascularized and all non-significant lesions (QFR > 0.80) were not; otherwise, the case was defined as QFR-discordant revascularization. Patient-oriented composite end-point (POCE) of cardiac death, myocardial infarction and unscheduled revascularization was the primary endpoint. ResultsA total of 803 patients from six high-volume centers were included. Canadian Cardiovascular Society (CCS) class II angina was the most frequent (48.9%) clinical presentation. Median of follow-up was 68.8 months. 3vQFR was an independent predictor of POCE (HR 1.79 CI95% 1.01–3.18), with 2.75 as optimal cut-off value, irrespective of the therapy received. QFR-discordant revascularization (QFR+/Revascularization- or QFR-/Revascularization+) was an independent predictor of POCE in multivariate analysis (HR 1.65, CI 95% 1.03–2.64). ConclusionGlobal burden of epicardial coronary atherosclerosis, as evaluated by 3vQFR, as well as QFR-discordant therapy are independent predictors of adverse clinical outcome at long-term follow-up in stable coronary artery disease.