Intermediate Coronary Artery Stenosis Research Articles

Safety and efficacy of antiplatelet therapy in patients with intermediate coronary artery stenosis and deferred revascularization

Introduction and objectives: This study investigated the safety and efficacy of antiplatelet therapy in patients with intermediate coronary artery stenosis who underwent deferred revascularization due to their fractional flow reserve (FFR).Methods: A nationwide cohort study was conducted using the Korean National Health Insurance Service database. A total of 4657 patients with intermediate coronary artery stenosis who underwent deferred revascularization due to their FFR were identified from 2013 to 2020. FFR was indicated in patients with no prior evidence of myocardial ischemia and intermediate coronary artery stenosis (50%-70%) as determined by quantitative coronary angiography. Patients were classified according to whether antiplatelet therapy was initiated after the index procedure. The primary efficacy outcome was major adverse cardiac and cerebrovascular events (MACCE), a composite of all-cause death, myocardial infarction, unplanned revascularization, and stroke, during a 5-year follow-up period. The primary safety outcome was any gastrointestinal bleeding.Results: After propensity score matching, there were 1634 patients in the antiplatelet therapy group and 1634 in the nonantiplatelet therapy group. The risk of MACCE was similar between the 2 groups (24.8% vs 24.7%; adjusted HR, 0.97; 95%CI, 0.84-1.13; P = 0.745). The risk of gastrointestinal bleeding was higher in the antiplatelet therapy group than in the nonantiplatelet therapy group (2.2% vs 1.2%; aHR, 2.07; 95%CI, 1.08-4.00). These results were similar in subgroup analyses.Conclusions: In patients with intermediate coronary artery stenosis who underwent deferred revascularization due to their FFR, antiplatelet therapy may increase the risk of gastrointestinal bleeding without reducing the risk of future ischemic events.

Antiplatelet agents in patients with intermediate coronary artery stenosis and deferred revascularization

Abstract Background There is no specific recommendation regarding optimal antiplatelet therapy after deferral of revascularization in patients with established coronary artery disease. Objectives The current study investigated safety and efficacy of antiplatelet therapy in patients with intermediate coronary artery stenosis in whom revascularization was deferred based on fractional flow reserve (FFR). Methods In the Korean National Health Insurance Service database 2013-2020, we identified 4,657 patients who had intermediate coronary artery disease on angiography for which revascularization was deferred based on FFR. During this period, reimbursement criteria of FFR were patients with no previous evidence of myocardial ischemia and intermediate coronary artery stenosis (50-70%) by quantitative coronary angiography. Patients were then classified into two groups according to initiation of antiplatelet therapy after the index procedure. Primary efficacy outcome was major adverse cardiac and cerebrovascular events (MACCE), a composite of all-cause death, myocardial infarction, unplanned revascularization, and stroke, during 5 years of follow-up. Primary safety outcome was any gastrointestinal bleeding. Results After propensity score matching in a 1:1 ratio, there were 1,634 patients in antiplatelet therapy group and 1,634 in no therapy group (total N=3,268). The risk of MACCE was similar between the two groups (24.8% vs. 24.7%; adjusted hazard ratio [aHR], 0.97; 95% confidence interval [CI], 0.84-1.13; P=0.745). However, the risk of any gastrointestinal bleeding was higher in antiplatelet therapy group than no therapy group (2.2% vs. 1.2%; aHR, 2.07, 95% CI, 1.08-4.00). These results were consistently found in subgroup analyses. Conclusions In patients with intermediate coronary artery stenosis with deferred revascularization based on FFR, antiplatelet therapy was not associated with reduced risk of ischemic events but increased risk of gastrointestinal bleeding.

Diastolic hyperemia-free ratio for the assessment of intermediate coronary artery stenosis in patients with hemodialysis

Abstract Background Diastolic hyperemia-free Ratio (DFR) is new resting index and uses a pragmatic definition by including areas below the average aortic pressure with negative slope. Hemodialysis (HD) exhibits left ventricular hypertrophy and impaired microcirculation. The relationship between DFR and fractional flow reserve (FFR) in the patients with HD has not been yet investigated. Purpose We aimed to compare the rate of physiological discordance between HD patients and non-HD patients, and to elucidate the best DFR cut-off value predicting less than 0.80 of FFR in HD patients. Methods We enrolled 761 consecutive patients (1033 vessels) who underwent both DFR and FFR in the intermediate coronary artery stenosis between July 2020 and December 2023 in our hospital. The cutoff values of DFR 0.89 or less and FFR 0.80 or less were used for the study. We compared the DFR values with FFR values between HD group and Non-HD group. Results HD group consisted of 110 patients and Non-HD group consisted of 651 patients. A good correlation between DFR and FFR was observed in HD group (R=0.780 ; p < 0.0001) and Non-HD group (R=0.770 ; p < 0.0001). The rate of physiological discordance between HD group and non-HD group was each 31.3% and 20.5% (p < 0.01). Receiver operating characteristic curve showed that a suitable cut off value of DFR for equivalent FFR value of 0.80 was 0.84 in HD group and 0.89 in Non-HD group, respectively (Figure). Conclusion In the patients with HD, DFR may overestimate intermediate coronary artery stenosis and the suitable cut off value was 0.84.2024 ESC HD DFR Figure

Relationship between diastolic hyperemia-free ratio and fractional flow reserve in patients with aortic valve stenosis

Abstract Background Diastolic hyperemia-free Ratio (DFR) is new resting index and uses a pragmatic definition by including areas below the average aortic pressure with negative slope. Aortic valve stenosis (AS) exhibits left ventricular hypertrophy and impaired microcirculation. The relationship between DFR and fractional flow reserve (FFR) in the patients with AS has not been yet investigated. Purpose We aimed to compare DFR and FFR in each of AS group and Non-AS group and to elucidate a suitable DFR cut-off value predicting less than 0.80 of FFR. Methods We enrolled 761 consecutive patients (1033 vessels) who underwent both DFR and FFR in the intermediate coronary artery stenosis between July 2020 and December 2023 in our hospital. We compared the DFR values with FFR values between AS group and Non-AS group. AS was defined as an aortic valve area of 1.5 cm2 or less, a mean aortic valve gradient of 20 mm Hg or more, or a peak aortic-jet velocity of 3.0 m/s or more. Results AS group consisted of 55 patients and Non-AS group consisted of 706 patients. A good correlation between DFR and FFR was observed in AS group (R=0.713; p < 0.0001) and Non-AS group (R=0.758; p < 0.0001). The patient backgrounds were similar between AS and Non-AS groups (Table). Regarding physiological findings, DFR in AS group was significantly lower than in Non-AS group (0.83 ± 0.12 vs. 0.88 ± 0.11, p < 0.0001), but FFR was similar (0.80 ± 0.07 vs. 0.81 ± 0.10, p = 0.12). Receiver operating characteristic curve showed that a suitable cut off value of DFR for equivalent FFR value of 0.80 was 0.85 in AS group and 0.89 in Non-AS group, respectively (Figure). Conclusion In the patients with AS, DFR may overestimate intermediate coronary artery stenosis and the suitable cut off value was 0.85.2024 ESC AS DFR Table2024 ESC AS DFR Figure

TCT-220 Virtual Stenting With Quantitative Flow Ratio as Tool to Predict the Hemodynamic Effect of Treating Intermediate Coronary Artery Stenosis

TCT-220 Virtual Stenting With Quantitative Flow Ratio as Tool to Predict the Hemodynamic Effect of Treating Intermediate Coronary Artery Stenosis

Combined assessment of fractional flow reserve, resting full-cycle ratio, and resting ratio of distal coronary to aortic pressure for clinical outcomes

BackgroundFractional flow reserve (FFR) and non-hyperemic indices are invasive standards for evaluating functional significance of coronary stenosis. However, data are limited about outcomes in vessels with concordant and discordant physiological results, particularly with a ratio of distal coronary to aortic pressure (Pd/Pa) at rest. MethodsThis was a single-center, retrospective, observational study. Coronary physiological indices including FFR, resting full-cycle ratio (RFR), and resting Pd/Pa were invasively evaluated in vessels with intermediate coronary artery stenosis. FFR ≤0.80, RFR ≤0.89, and resting Pd/Pa ≤0.92 were considered physiologically positive. Vessels were divided into three groups according to the results of FFR, RFR, and resting Pd/Pa: concordant positive (all positive for FFR, RFR, and resting Pd/Pa), concordant negative (all negative for FFR, RFR, and resting Pd/Pa), and discordant groups. The primary endpoint was target vessel failure (TVF) defined as a composite of cardiac death and target vessel myocardial infarction and unplanned revascularization. ResultsOf 987 vessels included, 311 (31.5 %), 263 (26.6 %), and 413 (41.9 %) were in the concordant positive, discordant, and concordant negative groups. During a median follow-up period of 417 (208–756) days, TVF occurred more frequently in the concordant positive group, followed by the discordant and concordant negative groups (7.7 % vs. 4.6 % vs. 2.4 %, p = 0.004). TVF increasingly accrued during long-term follow-up, while discordant results of RFR and resting Pd/Pa did not result in worse outcomes compared with negative RFR and resting Pd/Pa. ConclusionThe combined assessment of FFR with RFR and resting Pd/Pa stratified TVF risks in vessels with intermediate coronary stenosis.

Rapid and Precise Computation of Fractional Flow Reserve from Routine Two-Dimensional Coronary Angiograms Based on Fluid Mechanics: The Pilot FFR2D Study.

Objective: To present a novel pipeline for rapid and precise computation of fractional flow reserve from an analysis of routine two-dimensional coronary angiograms based on fluid mechanics equations (FFR2D). Material and methods: This was a pilot analytical study that was designed to assess the diagnostic performance of FFR2D versus the gold standard of FFR (threshold ≤ 0.80) measured with a pressure wire for the physiological assessment of intermediate coronary artery stenoses. In a single academic center, consecutive patients referred for diagnostic coronary angiography and potential revascularization between 1 September 2020 and 1 September 2022 were screened for eligibility. Routine two-dimensional angiograms at optimal viewing angles with minimal overlap and/or foreshortening were segmented semi-automatically to derive the vascular geometry of intermediate coronary lesions, and nonlinear pressure-flow mathematical relationships were applied to compute FFR2D. Results: Some 88 consecutive patients with a single intermediate coronary artery lesion were analyzed (LAD n = 74, RCA n = 9 and LCX n = 5; percent diameter stenosis of 45.7 ± 11.0%). The computed FFR2D was on average 0.821 ± 0.048 and correlated well with invasive FFR (r = 0.68, p < 0.001). There was very good agreement between FFR2D and invasive-wire FFR with minimal measurement bias (mean difference: 0.000 ± 0.048). The overall accuracy of FFR2D for diagnosing a critical epicardial artery stenosis was 90.9% (80 cases classified correctly out of 88 in total). FFR2D identified 24 true positives, 56 true negatives, 4 false positives, and 4 false negatives and predicted FFR ≤ 0.80 with a sensitivity of 85.7%, specificity of 93.3%, positive likelihood ratio of 13.0, and negative likelihood ratio of 0.15. FFR2D had a significantly better discriminatory capacity (area under the ROC curve: 0.95 [95% CI: 0.91-0.99]) compared to 50%DS on 2D-QCA (area under the ROC curve: 0.70 [95% CI: 0.59-0.82]; p = 0.0001) in predicting wire FFR ≤ 0.80. The median time of image analysis was 2 min and the median time of computation of the FFR2D results was 0.1 s. Conclusion: FFR2D may rapidly derive a precise image-based metric of fractional flow reserve with high diagnostic accuracy based on a single two-dimensional coronary angiogram.

Clinical Outcomes of Deferred Lesions by IVUS Versus FFR-Guided Treatment Decision.

There are limited data regarding the safety of deferral of percutaneous coronary intervention based on intravascular ultrasound (IVUS) findings. The current study sought to compare the prognosis between deferred lesions based on IVUS and fractional flow reserve (FFR)-guided treatment decision. This study is a post hoc analysis of the FLAVOUR randomized trial (Fractional Flow Reserve and Intravascular Ultrasound for Clinical Outcomes in Patients With Intermediate Stenosis) that compared 2-year clinical outcomes between IVUS- and FFR-guided treatment decision on intermediate coronary artery lesions using predefined criteria. In both IVUS and FFR groups, vessels were classified into deferred or revascularized vessels, and patients were classified as those with or without deferred lesions. Vessel-oriented composite outcomes (cardiac death, target vessel myocardial infarction, or target vessel revascularization) in deferred vessels and patient-oriented composite outcomes (death, myocardial infarction, or any revascularization) in patients with deferred lesions were compared between the IVUS and FFR groups. A total of 1682 patients and 1820 vessels were analyzed, of which 922 patients and 989 vessels were deferred. At 2 years, there was no difference in the cumulative incidence of vessel-oriented composite outcomes in deferred vessels between IVUS (n=375) and FFR (n=614) groups (3.8% versus 4.1%; hazard ratio, 0.91 [95% CI, 0.47-1.75]; P=0.77). The risk of vessel-oriented composite outcomes was comparable between deferred and revascularized vessels following treatment decision by IVUS (3.8% versus 3.5%; hazard ratio, 1.09 [95% CI, 0.54-2.19]; P=0.81) and FFR (4.1% versus 3.6%; hazard ratio, 1.14 [95% CI, 0.56-2.32]; P=0.72). In comparison of patient-oriented composite outcomes in patients with deferred lesions, there was no significant difference between the IVUS (n=357) and FFR (n=565) groups (6.2% versus 5.9%; hazard ratio, 1.05 [95% CI, 0.61-1.80]; P=0.86). In patients with intermediate coronary artery stenosis, deferral of percutaneous coronary intervention based on IVUS-guided treatment decision showed comparable risk of clinical events with FFR-guided treatment decision. URL: https://www.clinicaltrials.gov; Unique identifier: NCT02673424.

Diagnostic performance of noninvasive computed tomography-derived fractional flow reserve in patients with severe aortic stenosis

Abstract Background Noninvasive fractional flow reserve derived from coronary computed tomography angiography (FFRct) is developed as a decision-making tool in daily clinical practice. However, its diagnostic performance has not been sufficiently explored in patients with severe aortic stenosis (AS). Purpose To identify the diagnostic performance of FFRct in patients with severe AS using invasive fractional flow reserve (FFR) as the reference standard. Methods This study was a retrospective observational that included consecutive patients with severe AS undergoing TAVI who had concomitant intermediate coronary artery stenosis based on preoperative invasive coronary angiography. Preoperative invasive FFR and CT data preoperatively before TAVI were prospectively collected. Results We analyzed the data of patients with severe AS demonstrating intermediate coronary artery stenosis and compared the FFRct values with the invasive FFR values. Among 93 patients (100 vessels), the median FFR and FFRct (Q1, Q3) were 0.85 (0.78, 0.90) and 0.83 (0.72, 0.88), respectively. The FFRct values significantly correlated with the FFR values (r = 0.57; p &amp;lt; 0.0001). The vessel-based analysis of the accuracy of FFRct showed a sensitivity of 90.3%, specificity of 73.9%, positive predictive value of 60.9%, and negative predictive value of 94.4%. Conclusions FFRct demonstrated a significant correlation with invasive FFR and a high negative predictive value in patients with severe AS. These findings suggest that FFRct would be a clinically beneficial noninvasive tool for excluding functional coronary artery stenosis in patients with severe AS.

Clinical outcomes of deferred lesions by IVUS versus FFR-guided treatment decision: the FLAVOUR trial substudy

Abstract Background There is limited data regarding the safety of deferral of percutaneous coronary intervention (PCI) based on intravascular ultrasound (IVUS) findings. Current study sought to compare the prognosis between deferred lesions based on IVUS and FFR (fractional flow reserve)-guided treatment decision. Methods Study population was derived from FLAVOUR trial which is a multinational, open-label, randomized, and non-inferiority trial that compared 2-year clinical outcomes between IVUS and FFR-guided treatment decision using predefined criteria. In both IVUS and FFR groups, vessels were classified into deferred or revascularized vessels, and patients into those with or without deferred lesion. Vessel-oriented composite outcomes (VOCO) (cardiac death, target-vessel myocardial infarction, or target-vessel revascularization) in deferred vessels and patient-oriented composite outcomes (POCO) (death, myocardial infarction, or any revascularization) in patients with deferred lesion were compared between IVUS and FFR group. Results A total of 1682 patients and 1820 vessels were analyzed. At 2 years, there is no difference in cumulative incidence of VOCO in deferred vessels between IVUS and FFR groups (3.8% vs. 4.1%; hazard ratio [HR] 0.91; 95% confidence interval [CI] 0.47-1.75; P=0.771). The risk of VOCO was comparable between deferred and revascularized vessels following both IVUS (3.8% vs. 3.5%; HR 1.09; 95% CI 0.54-2.19; P=0.813) and FFR-guided treatment decision (4.1% vs. 3.6%; HR 1.14; 95% CI 0.56-2.32; P=0.715). In comparison of POCO in patients with deferred lesion, there was no significant difference between IVUS and FFR groups (6.2% vs. 5.9%; HR 1.05; 95% CI 0.61-1.80; P=0.856). Conclusion In patients with intermediate coronary artery stenosis, deferral of PCI based on IVUS-guided treatment decision showed comparable risk of clinical events with FFR-guided treatment decision.

Diagnostic accuracy of vessel fractional flow reserve compared to conventional diagnostic tools in patients with coronary artery stenosis

Abstract Background Wire-based fractional flow reserve (FFR) is currently the golden standard in a physiological assessment for intermediate coronary artery stenosis (CAS). However, the clinical advantage of FFR has been limited by its invasiveness. In the previous study with a small number of participants (334 patients), three-dimensional quantitative coronary angiography (3D-QCA)-based vessel FFR (vFFR) has shown non-inferiority to wire-based FFR in diagnostic accuracy. There has been no reports regarding the relationship between vFFR and other conventional physiological assessment tools. Methods The present study was a retrospective registry designed to evaluate the diagnostic accuracy of vFFR compared to the conventional reference standard (wire-based FFR ≤0.80). Between January 2019 and February 2022, patients with stable or unstable angina, and non-ST-elevation acute coronary syndrome who had undergone physiological assessments [wire-based FFR, instantaneous wave-free ratio (iFR), resting full-cycle ratio (RFR), and/or coronary computed tomography angiography-derived FFR (FFRCT)] before percutaneous coronary intervention were included for the present analysis. The exclusion criteria were ST-elevation myocardial infarction, previous coronary artery bypass grafting, cardiogenic shock, and adenosine intolerance. In the present study, we investigate the relationship between vFFR and conventional tools such as wire-based FFR, iFR, RFR, and/or FFRCT in patients with intermediate CAS, including multi-vessel disease, severe coronary calcium, in-stent restenosis, and hemodialysis. Results The study included 722 patients (mean age, 70±10 years; male, 80%) who underwent vFFR in 698 patients (97%), wire-based FFR in 711 (98%), iFR in 523 (72%), RFR in 109 (15%), and FFRCT in 48 (7%). Most patients presented stable angina (93%). In the present study, multi-vessel disease was identified only 20% of all. A total of 1108 target vessels were LAD in 549 (50%), LCx in 287 (26%), and RCA in 272 (24%), respectively. Bifurcation lesions and in-stent restenosis were present in 12% and 13%, respectively. The subjects were diagnosed several comorbidities, such as hypertension (77%), dyslipidemia (57%), diabetes mellitus (40%), and hemodialysis (12%). Overall, vFFR showed good correlations with wire-based FFR (r=0.70; p&amp;lt;0.001), IFR (r=0.57; p&amp;lt;0.001), and RFR (r=0.69; p&amp;lt;0.001). However, the correlation between vFFR and FFRCT was weak (r=0.36; p&amp;lt;0.001). Furthermore, vFFR had a good diagnostic accuracy (sensitivity, specificity, negative predictive value and positive predictive value; 81%, 88%, 82% and 87%, respectively) to identify the lesions with wire-based FFR≤0.80 (AUC, 0.87; 95% CI, 0.84-0.90; p&amp;lt;0.001). Conclusion In this large number cohort, the 3D-QCA based vFFR has a good correlation with wire-based FFR, and a high diagnostic accuracy to detect the lesion with FFR ≤ 0.80 even in patients with severe coronary calcification, in-stent restenosis, and hemodialysis.Scatter plotsBland-Altman plots

Effects of guiding catheter on franctional flow reserve and non-hyperemic pressure ratios for the assessment of coronary artery stenoses

Abstract Aims Non-hyperemic pressure-derived Indexes (NHPI) provide diagnostic efficacy equivalent to fractional flow reserve (FFR) to guide percutaneous coronary interventions. In the Disengage (Determination of Fractional Flow Reserve in Intermediate Coronary Stenosis With Guiding Catheter Disengagement) registry, selective decannulation of the guiding catheter (GC) within the coronary ostium during FFR assessment was associated with a significant overall decrease in FFR, particularly when the stenosis was located in the proximal and middle coronary segments. So far it is unclear what influence the selective cannulation of the catheter in the coronary artery ostium has on the NHPI. This prospective registry aimed to evaluate the influence of GC engagement within the coronary ostium on FFR and NHPI values. Methods and results In the DISENGAGE@Rest (Determination of Fractional Flow Reserve in Intermediate Coronary Stenosis With Guiding Catheter Disengagement) 133 patients with 164 intermediate coronary artery stenoses (40-90%) were enrolled. We evaluated: 1) the impact of GC engagement within the coronary ostium on FFR and NHPI values; 2) implications for clinical decision making; 3) the relationship between coronary physiology indices and study site (proximal, middle and distal coronary segments). Disengagement of GC was associated with a significant decrease in FFR (FFReng, 0.85±0.07 vs. FFRdis, 0.83±0.07; p&amp;lt; .001), Pd/Pa (Pd/Paeng, 0.94±0.05 vs. Pd/Padis, 0.93±0.05; p&amp;lt; .001) and RFR values (RFReng, 0.91±0.07 vs. RFRdis, 0.90±0.07; p= .018). This significant decrease in invasive physiologic indexes was driven by a significant increase in mean Pa value (Pa eng, 93±15 mm Hg vs. Pa dis, 97±15 for FFR; P &amp;lt; .001; Pa eng, 94±15 mm Hg vs Pa dis, 96±15 for Pd/Pa; P &amp;lt; .001 Pa eng, 95±15 mm Hg vs Pa dis, 97±15 for RFR; P &amp;lt; .001), without changes in mean Pd value. In 24 (15%), 12 (7%) and 17 (10%) lesions, FFR, RFR and Pd/Pa values, respectively, shifted below the cut-off point after GC disengagement with changes in clinical decision-making. There was a significant FFR change, but no NHPI, across different segments (ΔFFReng–FFRdis proximal 0.04±0.03 vs. ΔFFReng–FFRdis middle 0.02±0.02 vs. ΔFFReng–FFRdis distal 0.03±0.04; p= .018). Conclusions The results confirm a significant overall decrease in FFR after GC disengagement and extend this to Pd/Pa and RFR. In case of proximal coronary artery disease, GC disengagement should be performed in order not to underestimate the hemodynamic significance of the lesion under examination.

Direct wire pacing during measurement of fractional flow reserve: A randomized proof-of-concept noninferiority crossover trial.

Adenosine administration for fractional flow reserve (FFR) measurement may induce heart pauses. To assess the accuracy and tolerability of direct wire pacing (DWP) during measurement of FFR. Adults with at least one intermediate coronary artery stenosis (40%-80%) were consecutively enrolled between June 2021 and February 2022 in this randomized, noninferiority, crossover trial (NCT04970082) carried out in France. DWP was applied (DWP) or not (standard method) through the pressure guidewire used for FFR measurement during adenosine-induced maximal hyperaemia. Subjects were randomly assigned to the allocation sequence (DWP first or standard first). A 2-minute washout period was observed between the two FFR measurements performed for each stenosis. The primary endpoint was the reproducibility of FFR measurements between methods. A total of 150 focal lesions, presented by 94 subjects, were randomized (ratio: 1:1). The FFR values obtained with each method were nearly identical (R = 0.98, p = 0.005). The mean FFR difference of 0.00054 (95% confidence interval: 0.004 to 0.003) showed the noninferiority of FFR measurement with DWP vs. that with the standard method. Higher levels of chest discomfort were reported with DWP than with the standard method (0.61 ± 0.84 vs. 1.05 ± 0.89, p < 0.001), and a correlation was observed between the electrical sensations reported with DWP and chest discomfort (p < 0.001). Pauses (n = 20/148 lesions) were observed with the standard method, but did not correlate with chest discomfort (p = 0.21). No pauses were observed with DWP. DWP during FFR measurement resulted in accurate and reproducible FFR values, and eliminated the pauses induced by adenosine.

Invasive physiologic assessment of coronary artery stenosis by resting full-cycle ratio and fractional flow reserve: a prospective observational study

Resting full-cycle ratio (RFR), an alternative to fractional flow reserve (FFR) for evaluating intermediate coronary artery stenosis, helps reduce patients’ time, cost, and discomfort. However, the validation data for RFR and FFR are lacking. We aimed to assess the diagnostic accuracy of RFR and FFR and evaluate effective decision-making for revascularization using their values. Patients subjected to an invasive physiological study for intermediate coronary artery stenosis in Yongin Severance hospital between October 2020 and April 2022 were prospectively and consecutively recruited. We evaluated the correlation between RFR and FFR measurements and the diagnostic performance of RFR (≤ 0.89) versus FFR (≤ 0.80). In all, 474 intermediate coronary stenosis lesions from 400 patients were evaluated using RFR and FFR values. There was a strong linear relationship between RFR and FFR (r = 0.75, 95% CI 0.70–0.78, p < 0.01). Comparing diagnostic performance between RFR and FFR, RFR demonstrated diagnostic accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 85.0%, 80.0%, 86.7%, 67.1%, and 92.7%, respectively. We analyzed the RFR value in the hyperemia zone (0.86–0.93) according to positive (RFR: 0.86–0.89) and negative (RFR: 0.90–0.93) areas. PPV in positive area is 47.8% (95% Confidence Interval [CI]: 33.8% to 62.0%) and NPV in negative area is 87.7% (95% CI: 80.3% to 93.1%). Excellent correlation exists between RFR and FFR and the diagnostic value of RFR without hyperemia compared with FFR in establishing the accurate functional significance of coronary artery stenosis was shown. RFR alone could evaluate the functional significance of coronary artery stenosis without unnecessary hyperemia, except in the positive area.Trial registration: URL: http://trialsearch.who.int; Unique identifier: KCT0005255.

Microcatheter-versus wire-based measurement of the fractional flow reserve

Background Fractional flow reserve (FFR) guided-percutaneous interventions is nowadays the gold standard for optimal coronary artery revascularization. While multiple pressure guidewires have been validated, the use of microcatheter for FFR measurements is still a matter of debate. Objective The aim of this study was to investigate the crossing profile characteristics of the NAVVUS® microcatheter as compared with the COMETTM pressure wire. At the same time, we compared non-hyperaemic pressure ratio (NHPR) and FFR measurements of both systems. Method/materials In this retrospective study, all angiographically intermediate coronary artery stenoses each month were assessed, using either the NAVVUS® or the COMETTM pressure system, to receive coronary artery physiology assessment with NHPR and FFR measurements. The crossing profile of both systems was compared regarding objective coronary artery lesion characteristics using quantitative coronary analysis evaluation. Results Over a period of 4.5 years, we evaluated 213 coronary artery stenoses using one of the two coronary tools. We found a 9.2% crossing profile failure rate using the microcatheter, compared to 0.7% in the pressure wire group (p < .001). The crossing failure was significantly correlated with the presence of coronary artery calcifications and angulation (p = .042, p = .049, respectively). FFR values were comparable be- tween the two groups and were significantly lower in the presence of coronary calcifications and proportional to the degree of stenosis (p = .036, p = .010). Pressure drift was comparable. Conclusion Our observations are in line with other studies reporting the poor crossing profile of the NAVVUS® microcatheter. NHPR and FFR measures of both systems were well correlated.

Coronary Artery Stenosis Evaluation by Angiography-Derived FFR: Validation by Positron Emission Tomography and Invasive Thermodilution

BackgroundFractional flow reserve (FFR) derived from invasive coronary angiography (QFR) is promising for evaluation of intermediate coronary artery stenosis. ObjectivesThe authors aimed to compare the diagnostic performance of QFR and the guideline-recommended invasive FFR using 82Rubidium positron emission tomography (82Rb-PET) myocardial perfusion imaging as reference standard. MethodsThis is a prospective, observational study of symptomatic patients with suspected obstructive coronary artery disease on coronary computed tomography angiography (≥50% diameter stenosis in ≥1 vessel). All patients were referred to 82Rb-PET and invasive coronary angiography with FFR and QFR assessment of all intermediate (30%-90% diameter stenosis) stenoses. Main analyses included a comparison of the ability of QFR and FFR to identify reduced myocardial blood flow (<2 mL/g/min) during vasodilation and/or relative perfusion abnormalities (summed stress score ≥4 in ≥2 adjacent segments). ResultsA total of 250 patients (320 vessels) with indication for invasive physiological assessment were included. The continuous relationship of 82Rb-PET stress myocardial blood flow per 0.10 increase in FFR was +0.14 mL/g/min (95% CI: 0.07-0.21 mL/g/min) and +0.08 mL/g/min (95% CI: 0.02-0.14 mL/g/min) per 0.10 QFR increase. Using 82Rb-PET as reference, QFR and FFR had similar diagnostic performance on both a per-patient level (accuracy: 73%; 95% CI: 67%-79%; vs accuracy: 71%; 95% CI: 64%-78%) and per-vessel level (accuracy: 70%; 95% CI: 64%-75%; vs accuracy: 68%; 95% CI: 62%-73%). The per-vessel feasibility was 84% (95% CI: 80%-88%) for QFR and 88% (95% CI: 85%-92%) for FFR by intention-to-diagnose analysis. ConclusionsWith 82Rb-PET as reference modality, the wire-free QFR solution showed similar diagnostic accuracy as invasive FFR in evaluation of intermediate coronary stenosis. (DAN-NICAD – Danish Study of Non-Invasive Diagnostic Testing in Coronary Artery Disease; NCT02264717)

Changes in the Treatment Strategy Following Intracoronary Pressure Wire in a Contemporaneous Real-Life Cohort of Patients With Intermediate Coronary Stenosis. Results From a Nationwide Registry

BackgroundIntracoronary pressure wire is useful to guide revascularization in patients with coronary artery disease. AimsTo evaluate changes in diagnosis (coronary artery disease extent), treatment strategy and clinical results after intracoronary pressure wire study in real-life patients with intermediate coronary artery stenosis. MethodsObservational, prospective and multicenter registry of patients in whom pressure wire was performed. The extent of coronary artery disease and the treatment strategy based on clinical and angiographic criteria were recorded before and after intracoronary pressure wire guidance. 12-month incidence of MACE (cardiovascular death, non-fatal myocardial infarction or new revascularization of the target lesion) was assessed. Results1414 patients with 1781 lesions were included. Complications related to the procedure were reported in 42 patients (3.0 %). The extent of coronary artery disease changed in 771 patients (54.5 %). There was a change in treatment strategy in 779 patients (55.1 %) (18.0 % if medical treatment; 68.8 % if PCI; 58.9 % if surgery (p < 0.001 for PCI vs medical treatment; p = 0.041 for PCI vs CABG; p < 0.001 for medical treatment vs CABG)). In patients with PCI as the initial strategy, the change in strategy was associated with a lower rate of MACE (4.6 % vs 8.2 %, p = 0.034). ConclusionsThe use of intracoronary pressure wire was safe and led to the reclassification of the extent of coronary disease and change in the treatment strategy in more than half of the cases, especially in patients with PCI as initial treatment.

Comparative study of fractional flow reserve and diastolic pressure ratio using a guidewire with a sensor for measuring intravascular pressure

This study aimed to evaluate the correlation and diagnostic agreement between diastolic pressure ratio (dPR) and fractional flow reserve (FFR) in a Japanese real-world setting. Prospective multicenter observational study. This study included 100 patients with intermediate coronary artery stenosis at 4 Japanese hospitals. For these lesions, FFR and dPR were measured using a guidewire with a sensor and a monitor to measure intravascular pressure. The correlation and diagnostic agreement between FFR and dPR were assessed. When both FFR and dPR were negative or positive, the results were considered to be concordant. When one was positive and the other was negative, the result was regarded as discordant (positive discordance, FFR > 0.80 and dPR ≤ 0.89; negative discordance, FFR ≤ 0.80 and dPR > 0.89). Overall, the FFR and dPR were well-correlated (R = 0.841). FFR and dPR were concordant in 89% of cases (concordant normal, 43%; concordant abnormal, 46%) and discordant in 11% (positive discordance, 7%; negative discordance, 4%). No significant difference was observed in the rate of concordant results between patients with and without diabetes mellitus. The diagnostic concordance rate was significantly different among the 3 coronary arteries (right coronary artery, 93.3%; left anterior descending artery, 93.2%; and left circumflex artery, 58.3%; P = .001). Additionally, the rate of concordant results tended to be higher when using intravenous administration of adenosine than when using intracoronary bolus injection of nicorandil (adenosine, 95.1%; nicorandil, 84.7%; P = .103). We found that dPR was highly correlated with FFR, and diagnostic discordance was observed in 11% of the lesions. Several factors, including lesion location and medication for hyperemia, may cause the diagnostic discordance between dPR and FFR.

893 FUNCTIONAL ASSESSMENT OF INTERMEDIATE CORONARY ARTERY STENOSIS

Abstract Background FFR represents the gold standard to functionally assess the ischemic potential of intermediate coronary artery stenoses particularly in patients presenting with multivessel disease. However, it is still underused in the current practice. Less invasive techniques have been identified for the evaluation of intermediate stenosis. The Quantitative flow ratio (QFR), based on the angiography with 3D-reconstruction of the coronary artery and computational fluid dynamics, has been showed to well correlate with the FFR. The Angiography-DeriveD hEmoDynamic index (ADDED Index) has also been validated to assess the ischemic potential of intermediate coronary stenosis and was also found to well correlate with FFR. It considers the jeopardized subtended myocardium and the minimal lumen diameter calculated at the angiography. This study aimed to compare the ADDED Index with QFR in terms of diagnostic accuracy. Methods A retrospective observational study was conducted. We included all patients presenting with an intermediate stenosis assessed with QFR. Both QFR and ADDED Index were calculated. Correlation was studied using Pearson's r test and linear regression. Receiver operator characteristics curve analysis was also performed. Results A total of 54 patients presenting with either stable angina or acute coronary syndromes were enrolled and finally 62 intermediate stenoses were included. A significant correlation between the ADDED Index and QFR was found (r2=0,32, p &amp;lt;0.001) (Figure 1). At ROC analysis, and with the QFR as reference, the ADDED Index showed a significant and very high area under the curve (0.99 (0.99-1.00), p&amp;lt;0.001), Figure 2) suggesting the high accuracy for the assessment of the ischemic potential of intermediate coronary artery stenoses. Conclusion ADDED Index was found similar to the QFR in terms of accuracy for the functional assessment of intermediate coronary artery stenoses.

Evaluation of intracoronary hemodynamics identifies perturbations in vorticity

Background and objective: Coronary artery disease (CAD) is highly prevalent and associated with adverse events. Challenges have emerged in the treatment of intermediate coronary artery stenoses. These lesions are often interrogated with fractional flow reserve (FFR) testing to determine if a stenosis is likely to be causative for ischemia in a cardiac territory. This invasive test requires insertion of a pressure wire into a coronary vessel. Recently computational fluid dynamics (CFD) has been used to noninvasively assess fractional flow reserve in vessels reconstructed from medical imaging data. However, many of these simulations are unable to provide additional information about intravascular hemodynamics, including velocity, endothelial shear stress (ESS), and vorticity. We hypothesized that vorticity, which has demonstrated utility in the assessment of ventricular and aortic diseases, would also be an important hemodynamic factor in CAD.Methods: Three-dimensional (3D), patient-specific coronary artery geometries that included all vessels &amp;gt;1 mm in diameter were created from angiography data obtained from 10 patients who underwent diagnostic angiography and FFR testing (n = 9). A massively parallel CFD solver (HARVEY) was used to calculate coronary hemodynamic parameters including pressure, velocity, ESS, and vorticity. These simulations were validated by comparing velocity flow fields from simulation to both velocities derived from in vitro particle image velocimetry and to invasively acquired pressure wire-based data from clinical testing.Results: There was strong agreement between findings from CFD simulations and particle image velocimetry experimental testing (p &amp;lt; 0.01). CFD-FFR was also highly correlated with invasively measured FFR (ρ = 0.77, p = 0.01) with an average error of 5.9 ± 0.1%. CFD-FFR also had a strong inverse correlation with the vorticity (ρ = -0.86, p = 0.001). Simulations to determine the effect of the coronary stenosis on intravascular hemodynamics demonstrated significant differences in velocity and vorticity (both p &amp;lt; 0.05). Further evaluation of an angiographically normal appearing non-FFR coronary vessel in patients with CAD also demonstrated differences in vorticity when compared with FFR vessels (p &amp;lt; 0.05).Conclusion: The use of highly accurate 3D CFD-derived intravascular hemodynamics provides additional information beyond pressure measurements that can be used to calculate FFR. Vorticity is one parameter that is modified by a coronary stenosis and appears to be abnormal in angiographically normal vessels in patients with CAD, highlighting a possible use-case in preventative screening for early coronary disease.