Research on individualized distribution approach of coronary resting blood flow for noninvasive calculation of fractional flow reserve

Background and Objectives: The distribution of coronary resting blood flow is critical for accurately calculating the computed tomography (CT) angiography-derived fractional flow reserve (FFR CT ). However, the diagnostic accuracy of FFR CT calculated by the fixed exponents between two risk factors and coronary resting blood flow, including myocardial mass and diameter of the coronary artery branch, was insufficient compared with invasive fractional flow reserve (FFR). In this study, we proposed the individualized distribution of coronary resting blood flow based on coronary ultrasound blood flow measurement, to improve the diagnostic accuracy of FFR CT calculation. Methods: Five risk factors and an unknown coefficient K were integrated to calculate the individualized distribution of coronary resting blood flow. The K value was fit using the least square method based on coronary ultrasound blood flow measurement results of 30 volunteers. We developed a novel approach for calculating the individualized distribution of coronary resting blood flow and applied it to calculate FFR CT (FFR CTI ). Then, we tested the performance of the individualized distribution approach by comparing it with the approach proposed by Taylor based on coronary ultrasound blood flow measurement results of 13 volunteers. Finally, we tested the diagnostic accuracy of FFR CT calculated by two approaches in invasive FFR of 121 vessels with coronary stenosis. Results: We identified five risk factors and 6.83 x10 -5 for K value, including cardiac output, mean arterial pressure, myocardial mass, coronary artery volume, and diameter of the coronary artery branch, to calculate the individualized distribution of coronary resting blood flow. The mean square error of the individualized distribution approach (0.0088) was significantly less than that of the approach proposed by Taylor (0.0799). The diagnostic accuracy of FFR CTI calculated by the individualized distribution approach (91.74%) was higher than that of the approach proposed by Taylor (FFR CTT ) (82.64%). Conclusions: The individualized distribution approach of coronary resting blood flow can significantly improve the diagnostic accuracy of FFR CT calculation compared with invasive FFR, and support its wide clinical application for diagnosing myocardial ischemia caused by coronary stenosis. & COPY; 2023 Elsevier B.V. All rights reserved.