Olgac U, Poulikakos D, Saur SC, Alkadhi H, Kurtcuoglu V. Patient-specific three-dimensional simulation of LDL accumulation in a human left coronary artery in its healthy and atherosclerotic states. Am J Physiol Heart Circ Physiol 296: H1969 -H1982, 2009. First published March 27, 2009 doi:10.1152/ajpheart.01182.2008.-We calculate low-density lipoprotein (LDL) transport from blood into arterial walls in a three-dimensional, patient-specific model of a human left coronary artery. The in vivo anatomy data are obtained from computed tomography images of a patient with coronary artery disease. Models of the artery anatomy in its healthy and diseased states are derived after segmentation of the vessel lumen, with and without the detected plaque, respectively. Spatial shear stress distribution at the endothelium is determined through the reconstruction of the arterial blood flow field using computational fluid dynamics. The arterial endothelium is represented by a shear stress-dependent, threepore model, taking into account blood plasma and LDL passage through normal junctions, leaky junctions, and the vesicular pathway. Intraluminal pressures of 70 and 120 mmHg are employed as the normal and hypertensive operating pressures, respectively. By applying our model to both the healthy and diseased states, we show that the location of the plaque in the diseased state corresponds to one of the two sites with predicted high-LDL concentration in the healthy state. We further show that, in the diseased state, the site with high-LDL concentration has shifted distal to the plaque, which is in agreement with the clinical observation that plaques generally grow in the downstream direction. We also demonstrate that hypertension leads to increased number of regions with high-LDL concentration, elucidating one of the ways in which hypertension may promote atherosclerosis.low-density lipoprotein transport; lipid accumulation; patient-specific simulations; atherosclerosis; leaky junction ATHEROSCLEROSIS, A PROGRESSIVE disease characterized by the accumulation of lipids in the arterial walls, is the primary cause of heart disease and stroke (37). Locally elevated concentrations of low-density lipoprotein (LDL) are considered to be the initiator of atherosclerotic plaque formation (37,46,48). Therefore, transport of LDL into arterial walls has been the subject of various experimental (8,11,35,39,47,48) and computational investigations (2,29,43,50,52,53,55,56,59).Computational LDL transport models, as recently reviewed by Khakpour and Vafai (28), are categorized into three types: wall-free models, homogenous wall models, and multilayer wall models. In the simple wall-free models, fluid dynamics and LDL transport are calculated solely in the artery lumen. A constant filtration velocity and LDL flux, defined by an overall mass transfer coefficient, are generally applied on the lumenside artery surface. The main drawback of wall-free models is that they do not provide any information on the transmural flow and solute dynamics in the arterial...