Assessment Of Coronary Artery Stenosis Research Articles

Predictors of Diagnostic Inaccuracy of Detecting Coronary Artery Stenosis by Preprocedural CT Angiography in Patients Prior to Transcatheter Aortic Valve Implantation.

Background: The diagnostic performance of preprocedural CT angiography in detecting coronary artery disease (CAD) in patients scheduled for transcatheter aortic valve implantation (TAVI) has been reported. However, data on predictors of diagnostic inaccuracy are sparse. We sought to investigate clinical characteristics and imaging criteria that predict the inaccurate assessment of coronary artery stenosis based on pre-TAVI-CT. Methods: The patient- and vessel-level analysis of all CT datasets from 192 patients (mean age 82.1 ± 4.8 years; 63.5% female) without known CAD or severe renal dysfunction was performed retrospectively in a blinded fashion. Significant CAD was defined as a CAD-RADS™ 2.0 category ≥ 4 by CT. Invasive coronary angiography (ICA) served as the reference standard for relevant CAD (≥70% luminal diameter stenosis or fractional flow reserve ≤ 0.80). Pertinent clinical characteristics and imaging criteria of all true-positive (n = 71), false-positive (n = 30), false-negative (n = 4), and true-negative patient-level CT diagnoses (n = 87) for relevant stenosis according to ICA were assessed. Results: In the univariate per-patient analysis, the following parameters yielded discriminative power (p < 0.10) regarding inaccurate CAD assessment by pre-TAVI-CT: age, atrial fibrillation, scanner generation, and image quality. Factors independently associated with CT diagnostic inaccuracy were determined using multivariable logistic regression analysis: a younger age (odds ratio [OR] 0.87; 95% confidence interval [CI] 0.80 to 0.94; p < 0.01) and insufficient CT image quality (OR 0.6; CI 0.41 to 0.89; p < 0.01). Conclusions: Our results demonstrate younger age and poor CT image quality to predict less accurate CAD assessments by pre-TAVI-CT in comparison with ICA. Knowledge of these predictors may aid in more efficient coronary artery interpretations based on pre-TAVI-CT.

Effects of Guiding Catheter Disengagement on Resting Indexes for the Assessment of Coronary Artery Stenoses.

Effects of Guiding Catheter Disengagement on Resting Indexes for the Assessment of Coronary Artery Stenoses.

OUFR Versus FFR for Functional Assessment of Coronary Artery Stenosis in Patients With Unstable Angina.

OUFR Versus FFR for Functional Assessment of Coronary Artery Stenosis in Patients With Unstable Angina.

Assessment of the Severity of Intermediate Coronary Artery Stenosis Using the Systemic Inflammatory Response Index.

Background: Fractional Flow Reserve (FFR) is a method that enables the hemodynamic assessment of coronary artery stenosis. The Systemic Inflammatory Response Index (SIRI) is a new marker calculated by multiplying the neutrophil-to-lymphocyte ratio (NLR) with the monocyte count. It is indicative of the presence and severity of coronary artery disease. This study evaluates the relationship between the functional significance of FFR measurements and the SIRI in intermediate coronary stenosis. Methods: A total of 294 patients with 50-70% stenosis in their coronary arteries based on quantitative measurement following angiography who underwent FFR measurement were included in the study before the FFR procedure. Total and differential leukocyte counts and routine biochemical tests were performed. Results: A total of 37% of the patients were found to have a positive FFR, while 63% had a negative FFR. Significant differences were observed in the neutrophil count, monocyte count, Systemic Inflammation Response Index (SIRI), total cholesterol, and amount of adenosine used between the groups (p < 0.05). A SIRI value of 1.16 was 77% sensitive and 55% specific for FFR positivity. Multivariate logistic regression analysis identified the SIRI as an independent predictor of FFR positivity. Conclusions: Our study has demonstrated that high values of the SIRI may serve as a new biomarker for predicting FFR positivity.

Diagnostic Accuracy of Computational Fluid Dynamics-Based Fractional Flow Reserve Derived From Coronary Angiography: The ACCURATE Study.

Although fractional flow reserve (FFR) is the contemporary standard to detect hemodynamically significant coronary stenosis, it remains underused for the need of pressure wire and hyperemic stimulus. Coronary angiography-derived FFR could break through these barriers. The aim of this study was to assess the feasibility and performance of a novel diagnostic modality deriving FFR from invasive coronary angiography (AccuFFRangio) for coronary physiological assessment. The ACCURATE (Angiography-Derived Fractional Flow Reserve for Functional Evaluation of Coronary Artery Disease) study was a prospective, multicenter study conducted at 5 centers. Patients who had at least 1 lesion with a diameter stenosis of 30% to 90% were eligible. AccuFFRangio was measured on site in real time and compared with invasive FFR measurements in a blinded fashion. Primary end point was the diagnostic accuracy of AccuFFRangio in identifying functional relevant lesions. Between November 2020 and June 2021, pairwise analyses of AccuFFRangio and FFR were performed in 304 coronary arteries. AccuFFRangio showed good correlation (r=0.89; P<0.001) and agreement (mean difference: 0.01±0.06) with FFR. The diagnostic accuracy was 95.07% (95% CI, 91.99%-97.21%), which were significantly exceeded the prespecified target value (P<0.001). The sensitivity, specificity, and area under the receiver operating characteristic curve of 95.83% (95% CI, 89.67%-98.85%), 94.71% (95% CI, 90.73%-97.33%), and 0.972 (95% CI, 0.947-0.988), respectively. AccuFFRangio derived from coronary angiography alone has high diagnostic accuracy, sensitivity, and specificity compared with FFR. AccuFFRangio bears the potential for increasing the adoption of functional assessment of coronary artery stenosis and improving the use of physiological guided decision-making. URL: https://www.clinicaltrials.gov; Unique identifier: NCT04814550.

Pathophysiology, Diagnosis, and Management of Coronary Artery Disease inthe Setting of Atrial Fibrillation.

Atrial fibrillation (AF) and coronary artery disease are frequently associated and, when so, lead to a grim prognosis. Recent studies suggest the presence of interconnected pathophysiological pathways between the 2 conditions that can promote and aggravate each other, igniting a vicious cycle. Notwithstanding, in contrast with the attention dedicated to the management of antithrombotic treatment, research on other aspects of coronary artery disease in AF is only recently gaining traction. The clinical impact of correct assessment of coronary artery stenosis in AF is especially high, due to the antithrombotic therapy imposed by both AF and coronary stenting. Until recently, an in-depth characterization of coronary microcirculation in AF was lacking. However, contemporary studies indicate that coronary microvascular dysfunction is a frequent encounter in AF, possibly explaining the ischemic symptoms even in the absence of obstructive coronary artery disease and interfering with the use of pressure-based indices to evaluate the hemodynamic significance of coronary artery stenosis. This comprehensive review addresses our current knowledge on coronary physiology in AF and its repercussion on the invasive management of coronary artery disease in this setting.

Accuracy of analytically determined fractional flow reserve derived from coronary angiography for non-invasive assessment of coronary artery stenosis.

Fractional flow reserve (FFR) determined invasively has been globally accepted as the gold standard for determining the functional significance of coronary artery stenoses. However, despite its great importance, the invasive method has certain disadvantages, including the risk of vascular injuries, the need for vasodilation, and significant medical costs. That is why great attention was paid to the development of non-invasive methods that would enable reliable diagnosis without exposing patients to the risk of unwanted consequences. This paper aimed to create and verify an alternative, less resource- and time-demanding, non-invasive solution. The determination of FFR is based on the application of the fundamental laws of fluid dynamics. All energy losses in the coronary artery with stenosis were identified and analyzed in detail. A three-dimensional model of a coronary artery was generated using the corresponding angiographic images. Finally, the pressure due to stenosis was calculated and the FFR was determined. The results obtained using the proposed analytical method were compared with available experimental data for 40 patients who experienced the invasive coronary angiography. The coefficient of determination, mean difference and standard deviation values are determined to be 0.726, -0.017 and 0.056, respectively. These values were slightly higher for FFR values above 0.80. The FFR calculated by the proposed analytical method has a relatively good correlation with clinical data, which leads to the conclusion that it can provide a reliable assessment of the functional significance of coronary stenosis.

Diagnostic accuracy of automatic quantitative flow ratio for hemodynamic assessment of coronary artery stenosis: prospective observational study

Abstract Background Quantitative flow ratio (QFR) is a method for evaluating fractional flow reserve (FFR) without the use of an invasive coronary pressure wire or pharmacological hyperemic agent. Automatic QFR (auto QFR) is a recently developed, simpler method of calculating QFR that uses a patient-specific TIMI (Thrombolysis in Myocardial Infarction) frame count, but with automatically specified start and end frames. Although the previous studies demonstrated that contrast QFR is more accurate than fixed QFR, there is no evidence for auto QFR. Purpose The aim of this study was to evaluate the diagnostic performance of auto QFR, fixed QFR, and contrast QFR for the diagnosis of hemodynamically significant coronary stenosis defined by FFR ≤0.80. Methods This prospective, multicentre trial enrolled patients suspected with coronary artery disease undergoing diagnostic coronary angiography with an indication for to perform invasive FFR. QFR was calculated at a blinded core laboratory. The primary endpoint was the diagnostic accuracy of auto QFR, fixed QFR, and contrast QFR to determine hemodynamically significant coronary stenosis using invasive FFR (≤0.80) as a reference standard. Results A total of 325 vessels from 274 patients were analysed. Mean FFR was 0.82±0.09, mean auto QFR was 0.80±0.12, and mean contrast QFR was 0.82±0.11, respectively. The overall diagnostic accuracy for identifying an FFR of ≤0.80 was highest by contrast QFR (81.5%), followed by fixed QFR (79.1%), and auto QFR (77.5%). The AUC was higher for contrast QFR (AUC 0.885; 95% CI: 0.845-0.925) than fixed QFR (AUC 0.856; 95% CI: 0.812-0.900) or auto QFR (AUC 0.854; 95% CI: 0.806-0.901), but did not differ significantly between fixed QFR and auto QFR (Figure). Conclusions There was no significant difference in AUC between fixed and auto QFR, but the accuracy of contrast QFR was significantly higher compared to both QFRs. Auto QFR has the advantage of faster computation time while using patient-specific coronary flow, but accuracy still needs to be improved.

Impact of ultra-high-resolution on cardiac CT assessment of coronary artery stenoses, plaque burden/composition, and pericoronary adipose tissue attenuation

Abstract Background Conventional coronary computed tomography angiography (CCTA) overestimates stenoses within stents and calcified arteries due to "blooming" artifacts. Ultra-high-resolution coronary CT (UHR-CT) may overcome this limitation because of higher spatial resolution. Purpose To investigate differences in coronary arterial lumen volume, stenosis severity, and plaque composition, between CCTA and UHRCT in patients with stents and/or high coronary calcium scores. Methods As part of a prospective pilot study, 14 patients referred for invasive coronary angiography for evaluation of obstructive CAD underwent UHRCT (Canon Precision, 160 x 0.25mm slices) prior to catheterization. Images of identical cardiac phases were reconstructed in two badges for comparison: 1) Ultra-high resolution using a 1,024 x 1,024 matrix, 0.25 mm, and 2) conventional resolution with a 524 x 524 matrix, 0.5 mm. All images were reconstructed using iterative reconstruction algorithm (AIDR 3D) and a sharp kernel (FC05). For the left main and three coronary arteries, an automated contour analysis using a dedicated software (QAngioCT RE 3.2, Medis, Netherlands) was performed to compare conventional CCTA vs. UHR-CT resolution images across common vascular and plaque metrics, including lumen and vessel volume, plaque burden/volume, plaque composition based upon predefined fixed intensity cut-off values of CT attenuation, minimal and maximal plaque thickness, pericoronary adipose tissue attenuation (PCAT), minimal lumen area and diameter, and diameter stenosis. All lumen and vessel contours were generated by the software, without manual editing. The segment model proposed by the SCCT was used as reference and the lesions classified as greater than 25% stenosis by visual assessment were recorded. The quality of the images was subjectively assessed using a 5-point Likert scale. Vessel segments with scores 1 (severe artifacts) and 2 (pronounced artifacts) were not included in the analysis. Results The mean patient age was 68.5 years (±6.8), 2 were female (14.3%), 6 patients had stents (11 stented segments) and the mean Agatston score was 947.6 (±449) among the 8 non-stented patients. A total of 56 vessels, 133 segments, and 57 lesions were analyzed. Eight segments (6%) were excluded from the analysis due to poor quality. Results on a per segment and per lesion basis were summarized in the table. The mean PCAT value was significantly lower for the UHRCT images compared to NR reconstruction in both segment (p&amp;lt;0.001) and lesion based (p=0.002) analyses. Plaque differentiation varied by UHRCT resulted in a lower fibrous plaque volumes but higher necrotic (low attenuation) plaque volumes. Conclusions Ultra-high-resolution CT image analysis results in significantly different coronary artery plaque volume and PCAT assessment vs. conventional resolution CCTA. These findings have implications for evaluating high-risk plaque features and perivascular inflammation in patients.Table 1

Single centre experience using vessel Fractional Flow Reserve (vFFR) and diagnostic performance compared with invasive Fractional Flow Reserve (FFR)

Abstract Background Fractional flow reserve (FFR) is a diagnostic gold standard in the functional assessment of coronary artery stenoses (1). Alternative invasive and non-invasive methods have been developed in an attempt to avoid limitations associated with FFR including added procedural risk, patient discomfort, time and cost. Vessel fractional flow reserve (vFFR) is a novel software using two angiographic projections to generate a 3D vessel reconstruction which has shown high diagnostic accuracy in predicting a positive FFR (2-4). Methods All patients undergoing coronary angiography between 01/10/2022 and 08/03/2023, where FFR was performed, were assessed. Patients were included where images met requirements necessary to use vFFR software. vFFR measurements were taken retrospectively by a single investigator and not used to inform patient care. Data were expressed as mean +/- standard deviation and %. The correlation of vFFR to FFR was compared using Pearson’s correlation coefficient. Receiving operator characteristic (ROC) area under the curve (AUC) analysis was used to determine diagnostic performance. Statistical analysis was performed using SPSS v27. Results 28 of 37 patients and 32 of 44 vessels were included and analysed with vFFR software. Excluded vessels were unsuitable due to insufficient frame rate or projection angulation during angiography. Mean age was 63 +/- 3.8 years and 75% of patients were male. Of 32 vessels assessed, 20 were LAD, 5 RCA, 5 LCx and 2 LMS. 29 of 32 vFFR values agreed with positive or negative FFR. Positive vFFR values were seen in all 15 vessels with positive FFR. 3 vessels received a positive vFFR where FFR values were negative. Mean vFFR was 0.76 +/- 0.1 and mean FFR was 0.81 +/- 0.09. vFFR correlated significantly with FFR (R=0.777, p&amp;lt;0.001). vFFR demonstrated good diagnostic accuracy in discriminating "positive" (&amp;gt;0.8) and "negative" (≤0.8) FFR with an AUC of 0.758 (95% CI 0.61-0.91, p&amp;lt;0.01). Conclusion vFFR correlated significantly with FFR and all positive FFR values also received positive vFFR values. vFFR demonstrated good diagnostic accuracy in predicting a positive FFR result. Thus, these data support a strategy of using a negative vFFR to avoid further testing.Pearson correlation of vFFR to invFFRROC curve: vFFR predicting invFFR

Comparison of Fractional Flow Reserve and Resting Full-Cycle Ratio in the Functional Assessment of Coronary Artery Stenosis in Patients with Non-ST-Segment Elevation Acute Coronary Syndrome.

This study investigated factors influencing discrepancies between fractional flow reserve (FFR) and resting full-cycle ratio (RFR) in the functional assessment of coronary artery stenosis in patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS). We included 320 diseased vessels from 253 consecutive patients with NSTE-ACS. Vessels were categorized into four groups based on FFR 0.80 and RFR 0.89 thresholds: group 1 concordant negative (RFR-/FFR-), group 2 positive RFR and negative FFR (RFR+/FFR-), group 3 negative RFR and positive FFR (RFR-/FFR+), and group 4 concordant positive (RFR+/FFR+). Univariate and multivariate logistic regression analyses were conducted to identify predictors of diagnostic discrepancy between FFR and RFR. Of the 320 diseased vessels, 182 (56.9%) were in group 1 (RFR-/FFR-), 33 (10.3%) in group 2 (RFR+/FFR-), 31 (9.7%) in group 3 (RFR-/FFR+), and 74 (23.1%) in group 4 (RFR+/FFR+). The concordance between FFR and RFR was 80.0%. Notably, left anterior descending artery (LAD) lesions exhibited significantly lower consistency compared to non-LAD lesions (p = 0.001), with distinct differences in FFR and RFR values between these groups (p 0.001). The presence of a LAD lesion emerged as an independent predictor of diagnostic inconsistency between positive RFR and negative FFR measurements (p = 0.001). LAD involvement independently predicts diagnostic discrepancies between FFR and RFR in evaluating functional coronary artery stenosis in NSTE-ACS patients.

The potential of artificial intelligence in the assessment of coronary artery stenosis in follow-up CT examinations

Abstract Background Coronary CT angiography (CCTA) has become one of the main modalities for detecting coronary artery disease (CAD) and is now the first diagnostic choice in many patients. As a result, an increasing number of patients are being identified at an early stage of CAD, allowing effective early medical therapy to be initiated. In addition, CCTA offers the possibility of assessing disease progression and the effectiveness of therapy through follow-up examinations. However, the comparison of different CCTA studies is time-consuming and reader-dependent. The aim of this study was to evaluate the potential of artificial intelligence (AI) for assessing CAD progression in follow-up CCTA examinations. Methods 41 (30 men, 11 women, age: 62.8±7.2 years) patients who were referred for follow-up examinations by their attending physicians were included in this study. Image acquisition was performed on a third–generation dual-source CT scanner using an institutional standard protocol. A series with good image quality was chosen from the CCTA study, transferred to the on-site AI prototype and processed fully automatically. A consensus reading by two experienced readers was used as a reference. Coronary arteries with a diameter &amp;lt;2 mm were excluded from the analysis. Results The median baseline Coronary Artery Disease Reporting and Data System (CAD-RADS) category was 3 (2.0–3.0). The general agreement between AI and reference readers was good (ICC 0.88 (95% CI 0.82-0.92); n=82), with a maximum CAD-RADS difference of 1. After a follow-up period of 2.2±0.7 years, the CAD-RADS category was stable in 36 patients and increased in 5 patients. The agreement between the AI and reference readers regarding the assessment of disease progression was moderate (ICC 0.71 (95% CI 0.45-0.84)), with a maximum category difference of 1. Conclusion AI has great potential for assessing CAD progression in follow-up CCTA examinations. Further developments such as an improvement in artefact detection are required before it can be used in routine clinical practice. AI generated unfolded view

Anonymous comparative assessment by an academic core laboratory of four angiography-derived fractional flow ratio software in patients with pressure derived iFR and FFR

Abstract Background/Introduction Functional assessment of coronary artery stenoses plays an important role in guiding the clinical management of patients with ischemic heart disease. Software to compute angiography-derived fractional flow ratio (angio-FFR) have been validated against pressure-wire-derived FFR (PW-FFR) with an area under the receiver operator characteristic curve (AUC) of 0.93-0.97. However, it is unknown whether commercially available angio-FFR software are equally reliable, and to what extent each might over- or under-estimate the true functional severity of a coronary artery lesion. Purpose The aim of this study was to investigate the diagnostic accuracies of five angio-FFR software/methods by an independent core-lab in a prospective cohort of 390 vessels with carefully documented sites of PW instantaneous-wave-free ratio (PW-iFR) and PW-FFR. Methods One "matcher investigator (MI)" colocalized on angiography the sites of PW measurement with angio-FFR measurements and provided the same two optimal angiographic views and frame selection to independent analysts, who were blinded to invasive physiological results and results from other software. Results are anonymized and randomly presented. The AUC of each angio-FFR was compared with 2D-quantative coronary angiography percent diameter stenosis (2D-QCA%DS) using a 2-tailed paired comparison of ROC (DeLong’s method). Results All 5 software/methods yielded a high proportion of analysable vessels (A:100%, B:100%, C:92.1%, D:99.5%, E:92.1%). The AUC’s for predicting an FFR≤0.8 for software A, B, C, D, E, and 2D-QCA%DS were 0.75, 0.74, 0.74, 0.73, 0.73, and 0.65, respectively (Figure A). The AUC for each angio-FFR was significantly greater than that for 2D-QCA%DS. Furthermore, binary logistic regression analyses showed the predictors of false positives and false negative: severity of lesion stenosis, lesion location, microvascular resistance, and intermediate zone of angiography-derived FFR potentially reduce the diagnostic accuracy (Figure B). Conclusions This head-to-head comparison by an independent core-lab demonstrated that the diagnostic accuracy of various angio-FFR software for predicting a PW-FFR≤0.80 was useful, with a higher discrimination compared to 2D-QCA%DS, however it didn’t reach the diagnostic accuracy (AUC≥0.90) previously reported in validation studies of various vendors. The intrinsic clinical value of "angiography-derived FFR" therefore requires confirmation in large clinical trials.Figure AFigure B

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.

Abstract 12127: Diagnostic Performance of Fractional Flow Reserve, Instantaneous Wave-Free Ratio and Quantitative Flow Ratio, on the Same Patient and Procedure

Introduction: Contemporary percutaneous coronary intervention (PCI) seeks precision and physiological assessment of coronary artery stenosis. Fractional Flow Reserve (FFR) is currently the gold standard for lesion physiology assessment; however, it's invasive and expensive. Other modalities, such as Quantitative Flow Ratio (QFR) and Instantaneous Wave-Free Ratio (iFR), can also determine the functional repercussion of coronary stenosis less invasively. Hypothesis: The results of FFR, iFR, and QFR of the same lesion, obtained during the same PCI, demonstrate the significant diagnostic capability of iFR and QFR, compared with FFR. Methods: Retrospective and unicentric study with stable chronic heart disease patients who underwent PCI. For every angiographic lesion, FFR, iFR and QFR were realized during the PCI. QFR was performed by an X-ray technician, blinded to the FFR and iFR results. A descriptive analysis was performed, as well as a correlation between the three measurements with Pearson’s r, chi-square, and ROC curve; and Bland-Altman plot for the results of FFR and QFR. Results: Thirty-six lesions of 27 patients were analyzed. For FFR, stenosis was considered significant when the result was &lt;0.80, obtaining 17 lesions (52%) as significant; for iFR, it was &lt;0.89, obtaining 14 significant lesions (38%); and for QFR, it was &lt;0.85, resulting in 19 (52%) significant lesions. Considering that FFR is the actual gold standard, a ROC curve was used to analyze QFR, were the best cutoff value was 0.88 with a sensitivity of 88% and specificity of 64% (AUC of 0.86, 95% CI 0.736- 0.991, p&lt;0.001), while for iFR the best cutoff value was 0.90 with a sensitivity of 82% and specificity of 74% (AUC of 0.85, 95% CI 0.722-0.984, p&lt;0.001). Pearson’s r revealed a significant correlation between FFR-iFR (r=0.6, p&lt;0.001), FFR-QFR (r=0.58, p&lt;0.001), and QFR-iFR (r=0.62, p&lt;0.001). Bland-Altman plot showed no significant difference between the data obtained with FFR and QFR. Chi-square test determined (p&lt;0.001) that the three angiographic methods had a good correlation in determining whether a lesion was significant. Conclusion: The study demonstrated the significant diagnostic capability that the QFR and iFR methods have, when compared against the current gold standard FFR.

Abstract 15380: Diagnostic Performance of Ultrasonic Flow Ratio versus Quantitative Flow Ratio for Assessment of Coronary Artery Stenosis

Introduction: Ultrasonic flow ratio (UFR) is a novel intravascular ultrasound (IVUS)-derived method for fast computation of fractional flow reserve (FFR) without pressure wires and adenosine. Aims: The aim of this study was to evaluate the diagnostic performance of UFR and compare it with angiography-based quantitative flow ratio (QFR), using FFR as the reference standard. Methods: Patients who underwent coronary angiography, IVUS and FFR were analyzed. UFR and QFR was computed offline in a central core-lab by independent analysts blinded to FFR. Results: A total of 111 paired comparisons between UFR, QFR and FFR from 56 patients were analyzed. UFR showed a numerically better correlation (r=0.83 vs. 0.79; p=0.27) and significant better agreement (standard deviation of the difference=0.07 vs. 0.08; p=0.02) with FFR than QFR. Diagnostic accuracy, sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio and negative likelihood ratio for UFR to predict FFR was 92% (95% CI: 85%-96%), 85% (95% CI: 71%-94%), 97% (95% CI: 89%-99%), 95% (95% CI: 83%-99%), 90% (95% CI: 82%-95%), 27.6 (95% CI: 7.0-108.4), and 0.16 (95% CI: 0.08-0.31), respectively. The area under curve for UFR to predict an FFR ≤ 0.80 was 0.94, is equivalent to QFR (difference=0.04; p=0.23), and higher than minimal lumen area (difference=0.09, p=0.006). Diagnostic accuracy was not significantly different in bifurcation lesions, nor in non-bifurcation lesions. Conclusions: The UFR showed good diagnostic concordance with FFR, equivalent to QFR. The good diagnostic performance of UFR provides a potentiality for the integration of physiological assessment and intravascular imaging in real-world clinical practice.

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.

Invasive Functional Assessment of Coronary Artery Disease in Patients with Severe Aortic Stenosis in the TAVI Era.

Coronary artery disease (CAD) is a common finding in patients suffering from aortic valve stenosis (AS), with a prevalence of over 50% in patients 70 years of age or older. Transcatheter aortic valve intervention (TAVI) is the standard treatment option for patients with severe AS and at least 75 years of age. Current guidelines recommend percutaneous coronary intervention (PCI) in patients planned for TAVI with stenoses of >70% in the proximal segments of non-left main coronary arteries and in >50% of left main stenoses. While the guidelines on myocardial revascularization clearly recommend functional assessment of coronary artery stenoses of less than 90% in the absence of non-invasive ischemia testing, a statement regarding invasive functional testing in AS patients with concomitant CAD is lacking in the recently published guideline on the management of valvular heart disease. This review aims to provide an overview of the hemodynamic background in AS patients, discusses and summarizes the current evidence of invasive functional testing in patients with severe AS, and gives a future perspective on the ongoing trials on that topic.

Photon-counting detector CT enables more precise assessment of coronary artery stenosis

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Hungarian Academy of Sciences. Introduction In contrast to conventional energy-integrating detectors, photon-counting detector (PCD) CT translates the photon energy directly to electric signal, which allows image acquisition with lower noise and improved spatial resolution. Objective The aim of our study was to assess coronary stenosis by comparing conventional CT and PCD-CT. Method In our retrospective study, we included patients who underwent coronary CT angiography (CCTA) performed by PCD-CT between January and December 2022. The control population consisted of consecutive patients who underwent coronary CCTA with a 280-slice CT. In our study, heart transplanted patients, patients with stent, pacemaker or valve implantation, or non-diagnostic image quality were excluded. The degree of coronary stenosis was evaluated according to the following classification: normal coronary artery (0%), minimal (1–24%), mild (25–49%), moderate (50–69%), severe stenosis (70–99%) or occluded coronary artery (100%). Results A total of 812 consecutive patients were included in our study (n=401 control, n=412 PCD-CT). There was no difference between the two groups in mean age (58.1±11.9 vs. 58.7±12.8 years) and sex (48.4% vs. 42.6% female). We found a significant difference in the degree of CAD between conventional CT and PCD-CT as follows: normal coronary arteries 29 vs 26%; minimum 23 vs 31%; mild 20 vs 23%; moderate 15 vs 10%; severe 12 vs 9%; occluded 3 vs 2%, respectively (all p&amp;lt;0.001). Conclusions According to our preliminary results, PCD-CT is less likely to overestimate the degree of stenosis and can detect smaller plaques more precisely.

Functional Assessment of Coronary Artery Stenosis from Coronary Angiography and Computed Tomography: Angio-FFR vs. CT-FFR.

This study was designed to compare the diagnostic performance of angio-FFR and CT-FFR for detecting hemodynamically significant coronary stenosis. Angio-FFR and CT-FFR were measured in 110 patients (139 vessels) with stable coronary disease using invasive FFR as the reference standard. On per-patient basis, angio-FFR was highly correlated with FFR (r =0.78, p <0.001), while the correlation was moderate between CT-FFR and FFR (r =0.68, p <0.001). Diagnostic accuracy, sensitivity, and specificity for angio-FFR were 94.6%, 91.4%, and 96.0%, respectively; and those of CT-FFR were 91.8%, 91.4%, and 92%, respectively. Bland-Altman analysis showed that angio-FFR had a larger average difference and a smaller root mean squared deviation than CT-FFR compared with FFR (-0.014±0.056 vs. 0.0003±0.072). Angio-FFR had a slightly higher AUC than that of CT-FFR (0.946 vs. 0.935, p =0.750). Angio-FFR and CT-FFR computed from coronary images could be accurate and efficient computational tools for detecting lesion-specific ischemia of coronary artery stenosis. Angio-FFR and CT-FFR calculated based on the two types of images can both accurately diagnose functional ischemia of coronary stenosis. CT-FFR can act as a gatekeeper to the catheter room, assisting doctors in determining whether patients need to be screened by coronary angiography. Angio-FFR can be used in the catheter room to determine the functional significant stenosis for helping decision-making in revascularization.