Atherosclerotic indicators for blood-like fluids in 90-degree arterial-like bifurcations.
The identification of regions prone to atherogenesis in the arterial network is compounded by the complex, slow interaction of mechanical and biomechanical processes. In recent times simplifications to the analysis of the near wall hemodynamics have been sought-after to identify plaque prone regions. Mean parameters have been defined to analyze the common fluid mechanical hypotheses considering the role of wall shear stress (WSS) variations in the pathological changes to the endothelium. In this study well known WSS indicators are applied to varying flow conditions of blood-like fluids in a 90-degree arterial bifurcation. The conventional indicators identify two distinct, focal regions that correlate with a known plaque prone location near arterial bifurcations. The results however demonstrate that the interpretation of the indicators can be difficult under varying flow conditions unless complementary parameters are considered simultaneously. A new indicator is also suggested that extracts the peaks of the temporal WSS gradients (PTWSSGs) and is shown to co-incide well with plaque prone regions. The PTWSSG could be used as a complimentary atherogenic indicator in bifurcating arteries, thereby expanding cardiovascular disease studies to the consideration of alternative fluid mechanical hypotheses. The inclusion of a non-Newtonian model is important in predicting the WSS and temporal WSS gradient distributions near the bifurcation due to the separation bubble induced fluctuations in the shear. Atherogenic indicators could be misleading if non-Newtonian effects are excluded.
Linné FLOW Centre, KTH Mechanics, Royal Institute of Technology, Stockholm SE-100 44, Sweden.
Stevin
S
van Wyk
Linné FLOW Centre, KTH Mechanics, Royal Institute of Technology, Stockholm SE-100 44, Sweden. Electronic address: prahl@mech.kth.se.
Lisa
L
Prahl Wittberg
Linné FLOW Centre, KTH Mechanics, Royal Institute of Technology, Stockholm SE-100 44, Sweden.
Laszlo
L
Fuchs
D000465:Algorithms; D001158:Arteries / Q000473:pathology*; D050197:Atherosclerosis / Q000097:blood* / Q000175:diagnosis* / Q000503:physiopathology; D001783:Blood Flow Velocity; D003198:Computer Simulation; D006439:Hemodynamics; D006801:Humans; D008955:Models, Cardiovascular; D009991:Oscillometry; D033081:Shear Strength; D012984:Software; D013314:Stress, Mechanical; D013997:Time Factors; D014783:Viscosity
Atherogenic indicator; Atherosclerosis; Bifurcation; Blood; CFD; OSI; Residence time; Wall shear stress; Wall shear stress gradients