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TCTAP A-094 Non-invasive Assessment of Vessel-specific Coronary Blood Flow by Computational Analysis of Intracoronary Transluminal Attenuation Gradient
JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY, VOL. 69, NO. 16, SUPPL S, 2017
BACKGROUND The amount of subtending myocardium and physiological stenosis is frequently different between MV and SB. To identify coronary Side Branch (SB) supplying myocardial masswhich may benefit from revascularization. METHODS In this multi-center registry, 482 patients who underwent coronary CT angiography and Fractional Flow Reserve (FFR) measurement were enrolled. % Fractional Myocardial Mass (FMM), a fraction of Vessel-specific myocardial mass to the whole myocardium, was assessed in 5,860 MV or SB consisting 2,930 bifurcations. Physiological stenosis was defined by Fractional Flow Reserve (FFR) <0.80. Myocardial mass which may benefit from revascularization was defined by %FMM10%. RESULTS In the per-bifurcation analysis, MV supplied 1.5- to 9-fold larger myocardial mass compared with SB. Unlike left main bifurcation (N¼482), only one out of every five non-left main SB (N¼2,448) supplied %FMM10% (97% versus 21%, p<0.001). SB length73 mm could estimate %FMM10% (c-statistics¼0.85, p<0.001). In 604 vessels interrogated by FFR, diameter stenosis was similar (p¼NS) but % FMM10%, FMM/minimal luminal diameter, and frequency of FFR<0.80 was higher in MV compared with SB (p<0.001, all). Generalized estimating equations modeling demonstrate that vessel diameter, left myocardial mass, and FFR were not (p¼NS) but SB length73 mm and left the main bifurcation were significant predictors for %FMM10% (p<0.001).
CONCLUSION Compared with MV, SB supplies smaller myocardial mass and showed less physiological severity despite similar stenosis severity. SB supplying the myocardial mass of %FMM10% which may benefit revascularization could be identified by vessel length73 mm. Pre-procedural recognition of these findings may guide optimal revascularization strategy for bifurcation. TCTAP A-094 Non-invasive Assessment of Vessel-specific Coronary Blood Flow by Computational Analysis of Intracoronary Transluminal Attenuation Gradient Il Park,1 Young Gyun Bae,2 Joo Myung Lee,1 Young-Joon Moon,2 Jin-Ho Choi1 1 Samsung Medical Center, Korea (Republic of); 2Computational Fluid Dynamics and Acoustics Laboratory, School of Mechanical Engineering, Korea Uni., Korea (Republic of)
S51
BACKGROUND The key role of a coronary artery is supplying sufficient blood flow that contains vital materials such as oxygen or glucose required by the myocardium. Therefore quantification of coronary blood flow (CBF) has paramount importance in the coronary physiology. However, absolute quantitation of vessel-specific CBF requires invasive cardiac catheterization and use of intracoronary wires with Doppler, pressure, or temperature probes. Non-invasive measurement of vessel-specific CBF from widely available modality would be very useful in clinical risk stratification and decisionmaking.
S52
JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY, VOL. 69, NO. 16, SUPPL S, 2017
METHODS Computational flow dynamics modeling investigated the rheological background of vessel-specific CBF-derived from transluminal attenuation flow encoding (TAFE), which consisted of arterial input function of contrast, vascular dimension to be filled by contrast, and transluminal attenuation gradient (TAG) reflecting intracoronary kinetics of contrast. TAFE formula was calibrated and validated with myocardial blood flow (MBF) by perfusion CT. TAFE-derived vessel-specific CBF of normal and obstructive vessels were compared in separated single-beat CCTA study. In both studies, the vessel-specific myocardial mass was calculated by %fractional myocardial mass (%FMM).
CONCLUSION TAFE enables easy-to-use non-invasive quantitative measurement of vessel-specific CBF from conventional CCTA. And shows good diagnostic performance for obstructive coronary artery disease compared to TAG. If we added TAFE to computational FFR, the performance of computational FFR would be improved. TCTAP A-095 An Integrated Scheme for Differentiating Hypertrophic Cardiomyopathy from Hypertensive Heart Disease Lingcong Kong1 Renji Hospital, School of Medicine, Shanghai Jiaotong University, China
1
RESULTS In the simulated model, TAFE-derived CBF matched well with computational CBF and decreased proportionally to the stenosis severity. In perfusion CT study (134 vessels, 30 patients), TAFE formula showed good correlation with absolute vessel-specific MBF (r¼0.87). In single-beat CCTA study (287 vessels, 98 patient), TAFEderived CBF decreased consistently according to the diameter stenosis (DS) of 0% to 70% (0.98 ml g-1 min-1 to 0.67 ml g-1 min-1, test for trend, p<0.01) The optimal cutoff of TAFE-derived CBF for DS50% was 0.89 ml g-1 min-1 and showed diagnostic performance with sensitivity 89%, specificity 66%, positive predictive value 46%, negative predictive value 95%, accuracy 71%.
BACKGROUND Differentiating hypertrophic cardiomyopathy (HCM) from hypertensive heart disease (HHD) unavoidably encounters diagnostic challenges in cases such as a patient with a history of hypertension was suspected with HCM. Diverse and overlapping forms of HCM can often lead to ambiguity when the diagnosis is based on a single genetic or morphological index. Combining feature tracking (FT) and late gadolinium enhancement (LGE) using cardiac magnetic resonance (CMR) imaging, we aim to identify the difference between the two disorders. METHODS Proposing and validation procedures were conducted in patients with documented HCM and HHD. Principal component analysis (PCA) was conducted on CMR indices selected by univariate analysis to model an integrated algorithm (IntA) in screening the two disorders. K-folding validation and second phase recruited subjects were to validate the algorithm.
BACKGROUND The amount of subtending myocardium and physiological stenosis is frequently different between MV and SB. To identify coronary Side Branch (SB) supplying myocardial masswhich may benefit from revascularization. METHODS In this multi-center registry, 482 patients who underwent coronary CT angiography and Fractional Flow Reserve (FFR) measurement were enrolled. % Fractional Myocardial Mass (FMM), a fraction of Vessel-specific myocardial mass to the whole myocardium, was assessed in 5,860 MV or SB consisting 2,930 bifurcations. Physiological stenosis was defined by Fractional Flow Reserve (FFR) <0.80. Myocardial mass which may benefit from revascularization was defined by %FMM10%. RESULTS In the per-bifurcation analysis, MV supplied 1.5- to 9-fold larger myocardial mass compared with SB. Unlike left main bifurcation (N¼482), only one out of every five non-left main SB (N¼2,448) supplied %FMM10% (97% versus 21%, p<0.001). SB length73 mm could estimate %FMM10% (c-statistics¼0.85, p<0.001). In 604 vessels interrogated by FFR, diameter stenosis was similar (p¼NS) but % FMM10%, FMM/minimal luminal diameter, and frequency of FFR<0.80 was higher in MV compared with SB (p<0.001, all). Generalized estimating equations modeling demonstrate that vessel diameter, left myocardial mass, and FFR were not (p¼NS) but SB length73 mm and left the main bifurcation were significant predictors for %FMM10% (p<0.001).
CONCLUSION Compared with MV, SB supplies smaller myocardial mass and showed less physiological severity despite similar stenosis severity. SB supplying the myocardial mass of %FMM10% which may benefit revascularization could be identified by vessel length73 mm. Pre-procedural recognition of these findings may guide optimal revascularization strategy for bifurcation. TCTAP A-094 Non-invasive Assessment of Vessel-specific Coronary Blood Flow by Computational Analysis of Intracoronary Transluminal Attenuation Gradient Il Park,1 Young Gyun Bae,2 Joo Myung Lee,1 Young-Joon Moon,2 Jin-Ho Choi1 1 Samsung Medical Center, Korea (Republic of); 2Computational Fluid Dynamics and Acoustics Laboratory, School of Mechanical Engineering, Korea Uni., Korea (Republic of)
S51
BACKGROUND The key role of a coronary artery is supplying sufficient blood flow that contains vital materials such as oxygen or glucose required by the myocardium. Therefore quantification of coronary blood flow (CBF) has paramount importance in the coronary physiology. However, absolute quantitation of vessel-specific CBF requires invasive cardiac catheterization and use of intracoronary wires with Doppler, pressure, or temperature probes. Non-invasive measurement of vessel-specific CBF from widely available modality would be very useful in clinical risk stratification and decisionmaking.
S52
JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY, VOL. 69, NO. 16, SUPPL S, 2017
METHODS Computational flow dynamics modeling investigated the rheological background of vessel-specific CBF-derived from transluminal attenuation flow encoding (TAFE), which consisted of arterial input function of contrast, vascular dimension to be filled by contrast, and transluminal attenuation gradient (TAG) reflecting intracoronary kinetics of contrast. TAFE formula was calibrated and validated with myocardial blood flow (MBF) by perfusion CT. TAFE-derived vessel-specific CBF of normal and obstructive vessels were compared in separated single-beat CCTA study. In both studies, the vessel-specific myocardial mass was calculated by %fractional myocardial mass (%FMM).
CONCLUSION TAFE enables easy-to-use non-invasive quantitative measurement of vessel-specific CBF from conventional CCTA. And shows good diagnostic performance for obstructive coronary artery disease compared to TAG. If we added TAFE to computational FFR, the performance of computational FFR would be improved. TCTAP A-095 An Integrated Scheme for Differentiating Hypertrophic Cardiomyopathy from Hypertensive Heart Disease Lingcong Kong1 Renji Hospital, School of Medicine, Shanghai Jiaotong University, China
1
RESULTS In the simulated model, TAFE-derived CBF matched well with computational CBF and decreased proportionally to the stenosis severity. In perfusion CT study (134 vessels, 30 patients), TAFE formula showed good correlation with absolute vessel-specific MBF (r¼0.87). In single-beat CCTA study (287 vessels, 98 patient), TAFEderived CBF decreased consistently according to the diameter stenosis (DS) of 0% to 70% (0.98 ml g-1 min-1 to 0.67 ml g-1 min-1, test for trend, p<0.01) The optimal cutoff of TAFE-derived CBF for DS50% was 0.89 ml g-1 min-1 and showed diagnostic performance with sensitivity 89%, specificity 66%, positive predictive value 46%, negative predictive value 95%, accuracy 71%.
BACKGROUND Differentiating hypertrophic cardiomyopathy (HCM) from hypertensive heart disease (HHD) unavoidably encounters diagnostic challenges in cases such as a patient with a history of hypertension was suspected with HCM. Diverse and overlapping forms of HCM can often lead to ambiguity when the diagnosis is based on a single genetic or morphological index. Combining feature tracking (FT) and late gadolinium enhancement (LGE) using cardiac magnetic resonance (CMR) imaging, we aim to identify the difference between the two disorders. METHODS Proposing and validation procedures were conducted in patients with documented HCM and HHD. Principal component analysis (PCA) was conducted on CMR indices selected by univariate analysis to model an integrated algorithm (IntA) in screening the two disorders. K-folding validation and second phase recruited subjects were to validate the algorithm.