Improved diagnostic accuracy of vessel-specific myocardial ischemia by coronary computed tomography angiography (CCTA).

Discrepancies between stenosis severity assessed at coronary computed tomography angiography (CCTA) and ischemia might depend on vessel type. Coronary plaque features are associated with ischemia. Thus, we evaluated the vessel-specific correlation of CCTA-derived diameter stenosis (DS) and invasive fractional flow reserve (FFR) and explored whether integrating morphological plaque features stratified by vessel might increase the predictive yield in identifying vessel-specific ischemia. Observational cohort study including patients undergoing CCTA for suspected coronary artery disease, with at least one vessel with DS ​≥ ​50 ​% at CCTA, undergoing invasive coronary angiography and FFR. Plaque analysis was performed using validated semi-automated software. Coronary vessels were stratified in left anterior descending (LAD), left circumflex (LCX), and right coronary artery (RCA). Per vessel independent predictors of ischemia among CCTA-derived anatomical and morphologic plaque features were tested at univariable and multivariable logistic regression analysis. The best cut-off to predict ischemia was determined by Youden's index. Ischemia was defined by FFR≤0.80. The study population consisted of 192 patients, of whom 224 vessels (61 ​% LAD, 19 ​% LCX, 20 ​% RCA) had lesions with DS ​≥ ​50 ​% interrogated by FFR. Despite similar DS, the rate of FFR≤0.80 was higher in the LAD compared to LCX and RCA (67.2 ​% vs 43.2 ​% and 44.2 ​%, respectively, p ​= ​0.018). A significant correlation between DS and FFR was observed only in LAD (p ​= ​0.003). At multivariable analysis stratified by vessel, the vessel-specific independent predictors of positive FFR were percent atheroma volume (threshold>17 ​%) for LAD, non-calcified plaque volume (threshold >130 ​mm3) for LCX, and lumen volume (threshold <844 ​mm3) for RCA. Integrating DS and vessel-specific morphological plaque features significantly increased the predictive yield for ischemia compared to DS alone (AUC ranging from 0.51 to 0.63 to 0.76-0.80). Integrating DS and vessel-specific morphological plaque features significantly increased the predictive yield for vessel-specific ischemia compared to DS alone, potentially improving patients' referral to the catheterization laboratory.

Belmonte M ，Paolisso P ，Gallinoro E ，Bertolone DT ，Leone A ，Esposito G ，Caglioni S ，Viscusi MM ，Bermpeis K ，Storozhenko T ，Wyffels E ，Bartunek J ，Sonck J ，Collet C ，Andreini D ，Vanderheyden M ，Penicka M ，Barbato E ... -  《-》

Correlation between hemodynamics assessed by FAI combined with CT-FFR and plaque characteristics in coronary artery stenosis.

While both CT-FFR and FAI are found to be associated with the development of CAD, their relationship with hemodynamics and plaque characteristics remains unclear. The present study aims to investigate the relationship between hemodynamics assessed by FAI combined with CT-FFR and plaque characteristics in functionally significant coronary artery stenosis. This retrospective study included 130 patients with suspected coronary heart disease, who were admitted to the Department of Cardiology of our hospital and underwent coronary computed tomography angiography (CCTA) from January 2022 to December 2023. Clinical baseline data and relevant auxiliary examination results were collected, and CCTA, FAI, and CT-FFR data were analyzed to investigate the relationship between these imaging parameters and both the hemodynamics and plaque characteristics of coronary artery lesions. From 130 patients, a total of 207 diseased vessels were analyzed and classified based on CAD-RADS grading: 128 vessels exhibited stenosis of less than 50%, and 79 exhibited stenosis exceeding 50%. Patients with more than one lesion of > 50% stenosis were classified into the myocardial ischemia group (44 cases), and the rest were categorized as the non-myocardial ischemia group (86 cases). Compared to the non-myocardial ischemia group, patients in the myocardial ischemia group were significantly older (p < 0.001). No significant difference was found between the two groups in sex, cardiovascular risk factors, or the indicator of stenotic vessel distribution. The minimum CT-FFR in vessels with < 50% stenosis was higher than in vessels with > 50% stenosis, ΔCT-FFR was lower in vessels with < 50% stenosis than in vessels with > 50% stenosis, and the median CT-FFR was significantly lower in vessels with > 50% stenosis than in vessels with < 50% stenosis (p < 0.001). Additionally, FAI-LAD, FAI-LCX, FAI-RCA, and FAI-Mean were found to be significantly higher in vessels with > 50% stenosis compared to vessels with < 50% stenosis (p < 0.05). A negative correlation was observed between the minimum CT-FFR among three main coronary arteries (LAD, LCX, RCA) and CAD-RADS classification, while both ΔCT-FFR and FAI were positively correlated with CAD-RADS classification (p < 0.05). Non-calcified plaques were more prevalent in the vessels with > 50% stenosis, primarily located in the LAD, while calcified plaques were predominantly observed in vessels with < 50% stenosis (p < 0.001). In addition, in vessels with > 50% stenosis, plaques were longer, the degree of luminal stenosis was greater, and both the total volume and burden of plaques were significantly greater than in vessels with < 50% stenosis (p < 0.001). Lastly, the FAIlesion value in the vessels with > 50% stenosis was higher than in vessels with < 50% stenosis (p < 0.001). FAI is associated with coronary artery stenosis and myocardial ischemia, and may serve as a novel indicator for identifying myocardial ischemia. Both FAI and CT-FFR demonstrated strong predictive abilities in significant coronary stenosis.

Duan B ，Deng S ，Xu R ，Wang Y ，He K ... -  《BMC MEDICAL IMAGING》

Accuracy of subtraction fractional flow reserve with computed tomography in identifying early revascularization in patients with coronary artery disease.

Zhu T ，Li D ，Qiao J ，Li Q ，Xu Y ，Ge B ，Xia L ... -  《-》

Incremental diagnostic value of coronary computed tomography angiography derived fractional flow reserve to detect ischemia.

Over the past decade, coronary computed tomographic angiography (CCTA) has been the most robust non-invasive method for evaluating significant coronary stenosis. Thanks to new technologies, it is now possible to determine the fractional flow reserve (FFR) non-invasively using computed tomographic (CT) images. The aim of this work was to evaluate the incremental diagnostic value of CT-derived FFR for ischemia detection. In this retrospective monocentric study, we investigated 421 patients who underwent CCTA and subsequent ischemia testing between 04/2009 and 06/2020. Endpoint was ischemia on a coronary vessel level assessed by CMR (n = 20), SPECT (n = 225), invasive angiography (stenosis ≥ 90%; n = 80) or invasive FFR (positive if ≤ 0.8; n = 96). CT-FFR was derived from CCTA images by a machine learning (ML) based software prototype. Patients averaged 66.5 [58.2-73.6] years of age and 72.7% (n = 306) were male. Overall, 52.5% (n = 221) had hypertension and 67.9% (n = 286) had hypercholesteremia. Logistic regression analysis on a per vessel base showed that the diagnostic model with CT-FFR plus CCTA had significantly better-fit criteria than the diagnostic model with CCTA alone (log-likelihood χ2 230.21 vs. 192.17; p for difference < 0.001). In particular, the area under curve (AUC) by receiver operating characteristics curve (ROC) analysis for CT-FFR plus CCTA (0.87) demonstrated greater discrimination of hemodynamic ischemia compared to CCTA alone (0.83; p for difference < 0.0001). Combined CCTA and CT-FFR have improved diagnostic accuracy compared to CCTA alone in detecting ischemia on the coronary vessel level and thus could reduce the use of invasive coronary angiography in the future.

Ried I ，Krinke I ，Adolf R ，Krönke M ，Moosavi SM ，Hendrich E ，Will A ，Bressem K ，Hadamitzky M ... -  《-》

Diagnostic Performance of Fractional Flow Reserve Derived From Coronary CT Angiography: The ACCURATE-CT Study.

AccuFFRct (ArteryFlow Technology) is a novel noninvasive method for calculating fractional flow reserve (FFR) from coronary computed tomography angiography (CCTA). The accuracy of AccuFFRct has not been adequately assessed. This study sought to evaluate the diagnostic performance of AccuFFRct in detecting lesion-specific ischemia. This prospective study enrolled 339 patients with 404 vessels. CCTA-derived FFR was calculated using an on-site computational fluid dynamics-based method and compared with invasive FFR. The performance of AccuFFRct was comprehensively analyzed in all lesions and subgroups, including "gray zone" lesions, various lesion classifications, clinical presentations, stenosis severities, and lesion locations. Using FFR ≤0.80 as a reference standard, the overall diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value for AccuFFRct were 90.6% (95% CI: 87.3%-93.3%), 90.9% (95% CI: 85.1%-94.9%), 90.4% (95% CI: 86.1%-93.8%), 85.3% (95% CI: 79.8%-89.5%), and 94.2% (95% CI: 90.8%-96.4%), respectively. Good correlation and agreement were found between the computed AccuFFRct and measured FFR. AccuFFRct showed superior discrimination ability to CCTA (AUC: 0.93 [95% CI: 0.89-0.95] vs 0.77 [95% CI: 0.72-0.81]; P < 0.001) and quantitative coronary angiography (AUC: 0.93 [95% CI: 0.89-0.95] vs 0.89 [95% CI: 0.85-0.92]; P = 0.048) for identifying functionally significant stenosis. Notably, AccuFFRct maintained high diagnostic accuracy across the spectrum of lesion classifications, clinical presentations, stenosis severities, lesion locations, and in the "gray zone". Furthermore, in the cohort with ≥70% stenosis, AccuFFRct could significantly reduce the rate of un-necessary invasive tests (33.1% vs 6.6%; P < 0.001). The study confirms the potential of AccuFFRct as a noninvasive alternative to invasive FFR for detecting ischemia in coronary artery disease and to risk stratify patients. The results highlight AccuFFRct's robust diagnostic ability across a wide range of lesion classifications, clinical presentations, stenosis severities, lesion locations, and in the "gray zone". (Diagnostic Performance of Fractional Flow Reserve Derived From Coronary CT Angiography [ACCURATE-CT]; NCT04426396).

Li C ，Hu Y ，Jiang J ，Dong L ，Sun Y ，Tang L ，Du C ，Yin D ，Jiang W ，Leng X ，Jiang F ，Pan Y ，Jiang X ，Zhou Z ，Koo BK ，Xiang J ，Wang J ，ACCURATE-CT Investigators ... -  《-》