The Importance of Hemorheology and Patient Anatomy on the Hemodynamics in the Inferior Vena Cava.
Inferior vena cava (IVC) filters have been used for nearly half a century to prevent pulmonary embolism in at-risk patients. However, complications with IVC filters remain common. In this study, we investigate the importance of considering the hemorheological and morphological effects on IVC hemodynamics by simulating Newtonian and non-Newtonian blood flow in three IVC models with varying levels of geometric idealization. Partial occlusion by an IVC filter and a thrombus is also considered. More than 99% of the infrarenal IVC volume is found to contain flow in the nonlinear region of the shear rate-viscosity curve for blood (less than 100 s-1) in the unoccluded IVCs. Newtonian simulations performed using the asymptotic viscosity for blood over-predict the non-Newtonian Reynolds numbers by more than a factor of two and under-predict the mean wall shear stress (WSS) by 28-54%. Agreement with the non-Newtonian simulations is better using a characteristic viscosity, but local WSS errors are still large (up to 50%) in the partially occluded cases. Secondary flow patterns in the IVC also depend on the viscosity model and IVC morphological complexity. Non-Newtonian simulations required only a marginal increase in computational expense compared with the Newtonian simulations. We recommend that future studies of IVC hemodynamics consider the effects of hemorheology and IVC morphology when accurate predictions of WSS and secondary flow features are desired.
Applied Research Laboratory, The Pennsylvania State University, University Park, PA, USA.|Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, USA.
Kenneth I
KI
Aycock
Applied Research Laboratory, The Pennsylvania State University, University Park, PA, USA.|Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, PA, USA.
Robert L
RL
Campbell
Department of Surgery, Penn State Hershey Medical Center, Hershey, PA, USA.
Frank C
FC
Lynch
Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, USA. kbm10@psu.edu.|Department of Surgery, Penn State Hershey Medical Center, Hershey, PA, USA. kbm10@psu.edu.
Keefe B
KB
Manning
Division of Applied Mechanics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, USA.
Brent A
BA
Craven
D018056:Hemorheology; D006801:Humans; D008955:Models, Cardiovascular; D013927:Thrombosis / Q000473:pathology / Q000503:physiopathology; D016306:Vena Cava Filters; D014682:Vena Cava, Inferior / Q000473:pathology / Q000503:physiopathology
Blood viscosity; Computational fluid dynamics; IVC filter; Non-Newtonian blood flow; Patient-specific modeling; Shear-rate histograms; Wall shear stress