Evaluation of functional significance of coronary arteries stenoses with estimation of fractional flow reserve based on computed tomography angiography data

Relevance. In patients with coronary artery disease (CAD) it is necessary to evaluate the functional significance of coronary tree lesion for determining of management and indications for myocardial revascularization. During invasive coronary angiography (ICA) it can be made by measurement of fractional flow reserve (FFR), which is called the «gold standard» of functional significance of coronary artery (CA) evaluation. For noninvasive visualization of CA is used coronary computed tomography angiography (CTA). The method of definition of FFR based on CTA data (FFRCT) – HeartFlow FFR-CT (HeartFlow, Redwood City, СА) has proved diagnostic accuracy and includes in clinical guidelines of American College of Cardiology. In Russian Federation there is no a software for FFRCT estimation, so algorithms are developed for this computation. Purpose. To provide comparative analysis of FFRCT and invasive measuring FFR (FFRINV) in patients with moderate stenoses of CA. Materials and methods. In trial included 20 patients with chest pain and suspected or known ischemic heart disease (IHD). As usual clinical and instrumental care was provided and acute myocardial infarction was excluded CTA on 640-slises computed tomography was performed. If CTA determine in one CA a moderate stenosis (50-85 %) the three-dimensional mathematical model of coronary tree was created with domestic algorithms of FFRCT calculation. FFRCT compared with FFRINV data, the mean of FFRINV equal or less than 0,8 indicated the functional significance of CA stenosis. Results. In final analysis of FFRCT and FFRINV parameters were included 13 patients. In 35 % cases a mathematical model for FFRCT calculation was not created because of severe calcification of CA. Correlation analysis shows the strong and statistically significant association between FFRCT and FFRINV parameters. Pearson coefficient is 0,86. Conclusions. Derived results revealed a good correlation between FFRCT and FFRINV in identifying of functional significance of CA stenoses. Despite of some limitations, method of noninvasive FFR calculation based on CTA data is a perspective direction of noninvasive examination development in patients with IHD. For future studying and using of method it is necessary to make algorithm of FFRCT calculation automatically and to provide trials with more including participants.