Репозиторий Университета

© 2019 The Authors International Journal for Numerical Methods in Biomedical Engineering Published by John Wiley  &  Sons Ltd Non-invasive coronary computed tomography (CT) angiography-derived fractional flow reserve (cFFR) is an emergent approach to determine the functional relevance of obstructive coronary lesions. Its feasibility and diagnostic performance has been reported in several studies. It is unclear if differences in sensitivity and specificity between these studies are due to study design, population, or "computational methodology." We evaluate the diagnostic performance of four different computational workflows for the prediction of cFFR using a limited data set of 10 patients, three based on reduced-order modelling and one based on a 3D rigid-wall model. The results for three of these methodologies yield similar accuracy of 6.5% to 10.5% mean absolute difference between computed and measured FFR. The main aspects of modelling which affected cFFR estimation were choice of inlet and outlet boundary conditions and estimation of flow distribution in the coronary network. One of the reduced-order models showed the lowest overall deviation from the clinical FFR measurements, indicating that reduced-order models are capable of a similar level of accuracy to a 3D model. In addition, this reduced-order model did not include a lumped pressure-drop model for a stenosis, which implies that the additional effort of isolating a stenosis and inserting a pressure-drop element in the spatial mesh may not be required for FFR estimation. The present benchmark study is the first of this kind, in which we attempt to homogenize the data required to compute FFR using mathematical models. The clinical data utilised in the cFFR workflows are made publicly available online.

© Am J Case Rep, 2018.  Objective: Unusual setting of medical care Background: Noninvasive assessment of the fractional flow reserve (FFR) in patients with coronary artery disease plays an important role in determining the need for revascularization. It is particularly relevant for patients with a borderline stenoses and painless myocardial ischemia. Our article describes the first clinical experience in the Russian Federation of using an automated method of noninvasive assessment of the fractional flow reserve (FFR ct ) with a one-dimensional (1-D) mathematical model in a patient with painless myocardial ischemia. Case Report: A 58-year-old male patient who underwent stent implantation in the left circumflex coronary artery (LCX) due to an acute non-ST-elevation posterior myocardial infarction had borderline stenoses of the left anterior descending artery (LAD). After stent implantation, there were no relapse angina symptoms on drug treatment, and according to our examination guideline for patients with borderline stenoses, a treadmill test was performed. The test was positive; therefore, FFR assessment was recommended, with coronary multi-slice CT being performed. The following results were obtained: FFR ct LAD – 0.57; FFR ct LCX – 0.88. An invasive assessment of FFR was also performed as a reference standard and revealed: FFR LAD – 0.6; FFR LCX – 0.88, and simultaneously a LAD percutaneous coronary intervention (PCI) was performed. Three months later, the patient underwent a stress test, which revealed no evidence of induced ischemia. Conclusions: Our method of noninvasive assessment of FFR has shown encouraging results, but we believe that larger-scale studies are needed to establish it as common clinical practice.

© 2018 Limited Liability Company KlinMed Consulting. All Rights Reserved. Nowadays an invasive evaluation of fractional flow reserve (FFR) is one of the main methods used for detecting lesions that cause ischemia. Invasively obtained FFR <0.75 has the specificity of 100%, and FFR >0.80 has the sensitivity >90%. Recent achievements in computational fluid dynamics and computer simulations allow noninvasive assessment of FFR using data obtained by CT angiography performed according to standard protocol at rest without additional radiation, modification of image acquisition protocols, or added medications for vasodilatation. The present review covers the results of the DISCOVER, the NXT, the DEFACTO and the PLATFORM randomized multicenter studies as well as the prospects of using a noninvasive method for measuring FFR developed by specialists of the Institute of Numerical Mathematics in collaboration with specialists of the I. M. Sechenov First Moscow State Medical University.