Diagnostic performance of intravascular ultrasound-based fractional flow reserve versus angiography-based quantitative flow ratio measurements for evaluating left main coronary artery stenosis.

We compared the diagnostic performance of the ultrasonic flow ratio (UFR) and quantitative flow ratio (QFR) for left main coronary artery (LMCA) stenosis. Evaluation of LMCA stenosis remains challenging because of its complex pathogenesis and severity. Computing QFR allows rapid determination of fractional flow reserve (FFR) from coronary angiograms. A novel intravascular ultrasound (IVUS)-based FFR (UFR) allows rapid FFR computation from IVUS images. Neither of the computational approaches required a pressure wire or hyperemia induction. Previous studies have validated the good diagnostic accuracy of QFR and UFR in identifying hemodynamically significant coronary stenosis using FFR as the reference standard. This retrospective observational study enrolled consecutive patients with intermediate-grade LMCA stenosis who underwent IVUS evaluation. UFR and QFR of all LMCA stenosis patients were assessed, their correlation and agreement were analyzed, and diagnostic performance of UFR in LMCA stenosis was evaluated. Eighty-three paired comparisons between UFR and QFR were obtained. UFR excellently correlated with QFR (r = 0.74, p < 0.01). The Bland-Altman plot showed good agreement between UFR and QFR (mean differences: 0.01 ± 0.05, p = 0.34). The area under the curve of UFR for identifying physiological LMCA stenosis was 0.97 (95% confidence interval [CI]: 0.93-1.00, p < 0.01). The overall UFR diagnostic accuracy was 0.95 (95% CI: 0.88-0.99). UFR showed excellent correlation and good agreement with QFR in LMCA stenosis assessment, indicating that it is highly feasible to use UFR for functional evaluation of LMCA stenosis.

Sui Y ，Yang M ，Xu Y ，Wu N ，Qian J ... -  《-》

Diagnostic performance of ultrasonic flow ratio versus quantitative flow ratio for assessment of coronary stenosis.

Yang C ，Sui YG ，Shen JY ，Guan CD ，Yu W ，Tu SX ，Wu YJ ，Qian J ... -  《-》

Accuracy of the angiography-based quantitative flow ratio in intermediate left main coronary artery lesions and comparison with visual estimation.

Revascularization of left main coronary artery (LMCA) stenosis is mostly based on angiography. Indices based on angiography might increase accuracy of the decision, although they have been scarcely used in LMCA. The objective of this study is to study the diagnostic agreement of QFR (quantitative flow ratio) with wire-based fractional flow reserve (FFR) in LMCA lesions and to compare with visual severity assessment. In a series of patients with invasive FFR assessment of intermediate LMCA stenoses we retrospectively compared the measured value of QFR with that of FFR and the estimate of significance from angiography. 107 QFR studies were included. The QFR intra-observer and inter-observer agreement was 87% and 82% respectively. The mean QFR-FFR difference was 0.047 ± 0.05 with a concordance of 90.7%, sensitivity 88.1%, specificity 92.3%, positive predictive value 88.1% and negative predictive value 92.3%. All these values were superior to those observed with the visual estimation which showed an intra- and inter-observer agreement of 73% and 72% respectively, besides 78% with the FFR value. The low diagnostic performance of the visual estimation and the acceptable performance of the QFR index measurement were observed in all subgroups analysed. QFR allows an acceptable estimate of the FFR obtained with intracoronary pressure guidewire in intermediate LMCA lesions, and clearly superior to the assessment based on angiography alone. The decision to revascularize patients with moderate LMCA lesions should not be based solely on the degree of angiographic stenosis.

Lopez-Palop R ，Carrillo P ，Leithold G ，Lozano I ，Nieto A ，Frutos A ，Garcia J ，Freites A ，Lacunza J ，Duran JM ，Hurtado J ，Gimeno JR ，Valdesuso R ，Pinar E ，Pascual D ... -  《-》

Correlation between 3D-QCA based FFR and quantitative lumen assessment by IVUS for left main coronary artery stenoses.

We aimed to evaluate the feasibility of using three dimensional-quantitative coronary angiography (3D-QCA) based fractional flow reserve (FFR) (vessel fractional flow reserve [vFFR], CAAS8.1, Pie Medical Imaging) and to correlate vFFR values with intravascular ultrasound (IVUS) for the evaluation of intermediate left main coronary artery (LMCA) stenosis. 3D-QCA derived FFR indices have been recently developed for less invasive functional lesion assessment. However, LMCA lesions were vastly under-represented in first validation studies. This observational single-center cohort study enrolled consecutive patients with stable angina, unstable angina, or non-ST-segment elevation myocardial infarction and nonostial, intermediate grade LMCA stenoses who underwent IVUS evaluation. vFFR was computed based on two angiograms with optimal LMCA stenosis projection and correlated with IVUS-derived minimal lumen area (MLA). A total of 256 patients with intermediate grade LMCA stenosis evaluated with IVUS were screened for eligibility; 147 patients met the clinical inclusion criteria and had a complete IVUS LMCA footage available, of them, 63 patients (63 lesions) underwent 3D-QCA and vFFR analyses. The main reason for screening failure was insufficient quality of the angiogram (51 patients,60.7%). Mean age was 65 ± 11 years, 75% were male. Overall, mean MLA within LMCA was 8.77 ± 3.17 mm2 , while mean vFFR was 0.87 ± 0.09. A correlation was observed between vFFR and LMCA MLA (r = .792, p = .001). The diagnostic accuracy of vFFR ≤0.8 in identifying lesions with MLA < 6.0 mm2 (sensitivity 98%, specificity 71.4%, area under the curve (AUC) 0.95, 95% confidence interval (CI) 0.89-1.00, p = .001) was good. In patients with good quality angiographic visualization of LMCA and available complete LMCA IVUS footage, 3D-QCA based vFFR assessment of LMCA disease correlates well to LMCA MLA as assessed by IVUS.

Tomaniak M ，Masdjedi K ，van Zandvoort LJ ，Neleman T ，Tovar Forero MN ，Vermaire A ，Kochman J ，Kardys I ，den Dekker W ，Wilschut J ，Diletti R ，de Jaegere P ，Van Mieghem NM ，Zijlstra F ，Daemen J ... -  《-》

Evaluation of Coronary Artery Stenosis by Quantitative Flow Ratio During Invasive Coronary Angiography: The WIFI II Study (Wire-Free Functional Imaging II).

Quantitative flow ratio (QFR) is a novel diagnostic modality for functional testing of coronary artery stenosis without the use of pressure wires and induction of hyperemia. QFR is based on computation of standard invasive coronary angiographic imaging. The purpose of WIFI II (Wire-Free Functional Imaging II) was to evaluate the feasibility and diagnostic performance of QFR in unselected consecutive patients. WIFI II was a predefined substudy to the Dan-NICAD study (Danish Study of Non-Invasive Diagnostic Testing in Coronary Artery Disease), referring 362 consecutive patients with suspected coronary artery disease on coronary computed tomographic angiography for diagnostic invasive coronary angiography. Fractional flow reserve (FFR) was measured in all segments with 30% to 90% diameter stenosis. Blinded observers calculated QFR (Medis Medical Imaging bv, The Netherlands) for comparison with FFR. FFR was measured in 292 lesions from 191 patients. Ten (5%) and 9 patients (5%) were excluded because of FFR and angiographic core laboratory criteria, respectively. QFR was successfully computed in 240 out of 255 lesions (94%) with a mean diameter stenosis of 50±12%. Mean difference between FFR and QFR was 0.01±0.08. QFR correctly classified 83% of the lesions using FFR with cutoff at 0.80 as reference standard. The area under the receiver operating characteristic curve was 0.86 (95% confidence interval, 0.81-0.91) with a sensitivity, specificity, negative predictive value, and positive predictive value of 77%, 86%, 75%, and 87%, respectively. A QFR-FFR hybrid approach based on the present results enables wire-free and adenosine-free procedures in 68% of cases. Functional lesion evaluation by QFR assessment showed good agreement and diagnostic accuracy compared with FFR. Studies comparing clinical outcome after QFR- and FFR-based diagnostic strategies are required. URL: https://www.clinicaltrials.gov. Unique identifier: NCT02264717.

Westra J ，Tu S ，Winther S ，Nissen L ，Vestergaard MB ，Andersen BK ，Holck EN ，Fox Maule C ，Johansen JK ，Andreasen LN ，Simonsen JK ，Zhang Y ，Kristensen SD ，Maeng M ，Kaltoft A ，Terkelsen CJ ，Krusell LR ，Jakobsen L ，Reiber JHC ，Lassen JF ，Bøttcher M ，Bøtker HE ，Christiansen EH ，Holm NR ... -  《-》