title: Functional and anatomical measures for outflow boundary conditions in atherosclerotic coronary bifurcations.
abstract: The aim of this research was finding the influence of anatomy-based and functional-based outflow boundary conditions for computational fluid dynamics (CFD) on fractional flow reserve (FFR) and wall shear stress (WSS) in mildly diseased coronary bifurcations. For 10 patient-specific bifurcations three simulations were set up with different outflow conditions, while the inflow was kept constant. First, the outflow conditions were based on the diameter of the outlets. Second, they were based on the volume estimates of the myocardium that depended on the outlets. Third, they were based on a myocardial flow measure derived from computed tomography perfusion imaging (CTP). The difference in outflow ratio between the perfusion-based and the diameter-based approach was -7 p.p. [-14 p.p.:7 p.p.] (median percentage point and interquartiles), and between the perfusion-based and volume-based this was -2 p.p. [-2 p.p.:1 p.p.]. Despite of these differences the computed FFRs matched very well. A quantitative analysis of the WSS results showed very high correlations between the methods with an r(2) ranging from 0.90 to 1.00. But despite the high correlations the diameter-based and volume-based approach generally underestimated the WSS compared to the perfusion-based approach. These differences disappeared after normalization. We demonstrated the potential of CTP for setting patient-specific boundary conditions for atherosclerotic coronary bifurcations. FFR and normalized WSS were unaffected by the variations in outflow ratios. In order to compute absolute WSS a functional measure to set the outflow ratio might be of added value in this type of vessels.
authors.affiliation: Department of Biomedical Engineering, Thorax center, Erasmus Medical Center, Gravendijkwal 230, Faculty Building, Ee 2302, 3000 CA Rotterdam, The Netherlands. Electronic address: j.schrauwen@erasmusmc.nl.
authors.forename: Jelle T C
authors.initials: JTC
authors.lastname: Schrauwen
authors.affiliation: Department of Radiology, Erasmus Medical Center, Rotterdam, The Netherlands; Department of Cardiology, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Adriaan
authors.initials: A
authors.lastname: Coenen
authors.affiliation: Department of Radiology, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Akira
authors.initials: A
authors.lastname: Kurata
authors.affiliation: Department of Biomedical Engineering, Thorax center, Erasmus Medical Center, Gravendijkwal 230, Faculty Building, Ee 2302, 3000 CA Rotterdam, The Netherlands.
authors.forename: Jolanda J
authors.initials: JJ
authors.lastname: Wentzel
authors.affiliation: Department of Biomedical Engineering, Thorax center, Erasmus Medical Center, Gravendijkwal 230, Faculty Building, Ee 2302, 3000 CA Rotterdam, The Netherlands; Department of Imaging Physics, Delft University of Technology, Delft, The Netherlands.
authors.forename: Antonius F W
authors.initials: AFW
authors.lastname: van der Steen
authors.affiliation: Department of Radiology, Erasmus Medical Center, Rotterdam, The Netherlands; Department of Cardiology, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Koen
authors.initials: K
authors.lastname: Nieman
authors.affiliation: Department of Biomedical Engineering, Thorax center, Erasmus Medical Center, Gravendijkwal 230, Faculty Building, Ee 2302, 3000 CA Rotterdam, The Netherlands.
authors.forename: Frank J H
authors.initials: FJH
authors.lastname: Gijsen
mesh_terms: D050197:Atherosclerosis / Q000473:pathology* / Q000503:physiopathology*; D003331:Coronary Vessels / Q000473:pathology* / Q000503:physiopathology*; D006801:Humans; D057446:Hydrodynamics; D008955:Models, Cardiovascular; D013314:Stress, Mechanical
keywords: CFD; CT-perfusion; Coronary arteries; FFR; Wall shear stress