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Title The Effects of Blood Pressure and Flow on Non-invasive Fractional Flow Reserve |
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Type Free Paper Session 1 |
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Theme ACC Asia & SCS 32nd Annual Scientific Meeting |
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Topic Basic Science |
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Main Author Junmei Zhang1 2 |
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Presenting Author Junmei Zhang1 2 |
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Co-Author Gaurav Chandola1 Ris Low1 Ru San Tan1 2 Aaron Sung Lung Wong1 2 Jack Wei Chieh Tan1 2 Khung Keong Yeo1 2 Ping Chai3 Lynette LS Teo3 Ching Ching Ong3 Adrian F Low3 Lohendran Baskaran1 Terrance Siang Jin Chua1 2 Tian Hai Koh1 2 Swee Yaw Tan1 2 Soo Teik Lim1 2 Liang Zhong1 2 |
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Department / Institution / Country National Heart Research Institute Singapore / National Heart Center Singapore / Singapore1 SingHealth Duke-NUS Cardiovascular Sciences ACP / Duke-NUS Medical School / Singapore2 Cardiology / National University Hospital Singapore / Singapore3 |
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Objective(s) From computed tomography coronary angiography (CTCA), we developed a methodology for non-invasive fractional flow reserve (FFRB) assessment using computational fluid dynamics (CFD), which has demonstrated good discrimination for coronary ischemic lesions. In this study, we aimed to assess the effects on FFRB of (1) blood pressure (BP); and (2) total coronary blood flow (CBF). |
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Material and Method All subjects underwent both CTCA and invasive FFR measurement. Ischemia was defined as invasive FFR ≤0.8. Using our developed reduced-order CFD algorithm, FFRB was computed with inputs of (1) BP measured before CTCA; and (2) estimated total CBF, which is conventionally calculated from left ventricular mass (LVM) assessed on CTCA. To evaluate the effects of BP and CBF, FFRB was also computed at graded levels of simulated BPs (70%BP, 80% BP, 90%BP, 110%BP, 120%BP, and 130%BP) and CBF (70%CBF, 80%CBF, 90%CBF, 110%CBF, 120%CBF, and 130%CBF) for each patient-specific CTCA-derived 3D coronary model. Correlation and agreement between FFRB and invasive FFR were assessed by the Pearson test and Bland-Altman analysis, respectively. |
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Result(s) 9 patients with 10 coronary lesions were studied. Mean invasive FFR and FFRB (derived using measured BP and estimated CBF values) were 0.787±0.0998 and 0.792±0.100, respectively. Correlation between FFRB and FFR was excellent (FFRB=0.9431FFR+0.0499, R=0.937, p<0.05, FFR-FFRB=-0.00514±0.0354). FFRB increased with the increasing magnitude of simulated BP, but decreased as simulated CBF increased. At simulated 70%BP, 80% BP, 90%BP, 110%BP, 120%BP, and 130%BP, the mean FFRB were 0.715±0.134, 0.747±0.119, 0.773±0.108, 0.810±0.092, 0.823±0.085, and 0.835±0.080, respectively. At simulated 70%CBF, 80%CBF, 90%CBF, 110%CBF, 120%CBF, and 130%CBF), mean FFRB were 0.817±0.088, 0.809±0.092, 0.801±0.095, 0.784±0.104, 0.775±0.109, and 0.767±0.113, respectively. |
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Conclusion Use of measured BP before CTCA procedure and CBF calculated from CTCA-estimated LVM are obligatory for accurate noninvasive FFRB assessment. BP and CBF variations have directionally opposite effects on FFRB calculation, and inaccurate assumptions can misclassify physiologic significance in borderline coronary lesions. |