Finite Element Analysis Of Fractional Flow Reserve Of The Coronary Artery Stenosis

Hemodynamics has significant impact on the occurrence and development of coronary artery stenosis. Fractional flow reserve(fractional flow reserve, FFR) has gradually become the gold standard for judging the pathological degree of coronary artery stenosis. FFR in clinical is obtained by measuring the pressure at the stenosis by invasive catheter. However, this invasive method has a lot of disadvantages, and noninvasive method is in urgent need. Currently, FFR obtained from finite element numerical simulation based on CTA(FFRCT) becomes a new perspective.Numerical and experimental studies were performed in this work to investigate the noninvasive method of FFR and its feasibility.Firstly, the study was verified by idealized models. Different idealized models of coronary artery stenosis based on clinical date were established in Pro/Engineering. The steady flow in the idealized models of coronary artery stenosis was numerically simulated by using computational fluid dynamics(Computational Fluid Dynamics, CFD). The pressure values at the distal end and proximal end of the stenosis were extracted to analyze the FFR of different models. Secondly, realistic models of coronary artery stenosis with soft and hard plaques respectively were reconstructed based on CTA data, and CFD approach was applied to the numerical simulation to obtain the FFRCT. The FFRCT was calculated and the relationship between the FFRCT and invasive FFR was analyzed. At last, animal experiments were accomplished for verification. The artificial stenosis was made at the proximal segments of left anterior descending coronary artery in minipigs. Then the 3-D models of the stenosis artery were reconstructed. The inlet boundary condition was the real velocity of the coronary artery entrance of the minipig which was measured by invasive method. The FFRCT was calculated by CFD, and then the relationship between the noninvasive FFRCT and invasive FFR was analyzed.The result can be got from the result of idealized models: The stenosis ratio, the length of stenosis, the number of stenosis, stenosis arc, and the stenosis offset have significant effect on FFR. The stenosis ratio and the number of stenosis have the most significant influence, while the distance between adjacent stenosis has little influence on FFR. The individual models tell that: The noninvasive FFRCT and invasive FFR have a high consistency. That is to say the noninvasive FFRCT calculated by CFD is feasible. The consistency of FFRCT and invasive FFR from hard plaques is lower than that from soft plaques. The animal experiment has the real inlet velocity, and this become a great innovation in noninvasive detection FFRCT.The noninvasive method through calculating FFRCT for evaluating myocardial ischemia is feasible. This study is the basis for clinical noninvasive FFR, and it has a good clinical application prospects.