(541e) Effective Physiological and Anatomical Parameters on Fractional Fluid Reserve (FFR) of Coronary Artery Stenosis

Authors: 
Hashemi, J., University of Louisville
Berson, R. E., University of Louisville
Ghafghazi, S., University of Louisville
Coronary stenosis is an abnormal narrowing in a coronary artery that is caused by an atherosclerotic lesion and reduces lumen space. FFR is a gold standard method to assess the hemodynamic significance of coronary stenosis. FFR is the ratio of maximum blood flow distal to a stenotic lesion to normal maximum flow in the same artery. Normal FFR is 1 and an FFR < 0.8 is considered hemodynamically significant. FFR is typically measured invasively in the cardiac catheterization laboratory using a pressure sensor wire in the coronary artery. Recently, investigators have applied computational fluid dynamics (CFD) methods to determine FFR using coronary images obtained from different modalities such as angiograms or CT scans. The purpose of this study was to determine the effect of eleven physiological and anatomical factors on the accuracy of computing FFR. In this study, blood flow was modeled as a single phase Newtonian fluid. The physiological factors were pressure as inlet boundary condition, mass flow rate as outlet boundary condition, heart rate, blood viscosity and blood density. Anatomical factors were the diameter of coronary artery, length of coronary segment modeled, percent stenosis, stenosis length, the position of stenosis relative to coronary segment modeled, and stenosis shape (concentric vs. eccentric stenoses). The parameters that affected FFR the most were determined by Plackett–Burman statistical analysis. Analysis of variance (ANOVA) showed a high variance coefficient (R2) value of 0.928. Our analysis demonstrated that percent stenosis, diameter of coronary artery, mass flow rate, and stenosis shape had the most significant effect on FFR (p < 0.05). Increase in mass flow rate decreased FFR significantly, while the diameter of the coronary artery was directly proportional to FFR. As for stenosis shape, FFR decreased more significantly due to concentric stenosis than eccentric stenosis. CFD provided analysis of coronary physiology that would have been difficult or impractical to do experimentally. Accurate anatomical reconstruction is critical for computationally deriving FFR.

Keywords: Fractional Fluid Reserve; Coronary Artery Stenosis; Plackett–Burman Method; Computational Fluid Dynamics;