Assessment of Hemolysis Related Quantities in a Microaxial Blood Pump by Computational Fluid Dynamics

Abstract

A computational assessment or even quantification of shear induced hemolysis in the predesign phase of artificial organs (e.g., cardiac assist devices) would largely decrease efforts and costs of design and development. In this article, a general approach of hemolysis analysis by means of computational fluid dynamics (CFD) is discussed. A validated computational model of a microaxial blood pump is used for detailed analysis of shear stress distribution. Several methods are presented that allow for a qualitative assessment of shear stress distribution and related exposure times using a Lagrangian approach and mass distribution in combination with shear stress analysis. The results show that CFD offers a convenient tool for the general assessment of shear-induced hemolysis. The determination of critical regions and an estimation of the amount of blood subject to potential damage in relation to the total mass flow are shown to be feasible. However, awareness of limitations and potential flaws in CFD based hemolysis assessments is crucial.

DPIV Prediction of Flow Induced Platelet Activation—Comparison to Numerical Predictions

“…1,5 Bluestein et al 3 measured platelet deposition in streamlined models of stenoses under steady flow and conducted numerical simulations to establish an activation level parameter (AL) based on a summation of the instantaneous product of the shear stress level and exposure time along turbulent trajectories. Steinman 18 developed a numerical method for visualizing periodic velocity data, based on the subdivision and sequential display of computed particle trajectories.…”

“…Apel et al 1 developed a convenient tool for the determination of critical regions and an estimation of the amount of blood subject to potential hemolysis damage using CFD in a microaxial blood pump.…”

A New Method for Assessing Haemolysis in a Rotary Blood Pump Using Large Eddy Simulations (LES)

“…They used Computational Fluid Dynamics (CFD) for this purpose. Also Arvand et al (2001) and Apel at al. (2001) have used CFD for haemolysis in their evaluation of artificial hearts.…”

“…The best way to evaluate haemolysis could be a direct calculation of hydrodynamic stresses inside the artificial heart (Apel et al, 2001;Bluestein and Mockros, 1969;Gregoriades et al, 2000). This is impossible by exclusively using CFD.…”

High-Resolution Measurement of the Unsteady Velocity Field to Evaluate Blood Damage Induced by a Mechanical Heart Valve

“…Temporal integration by a forward Euler scheme, already proposed for the treatment of similar numerical data 38 , introduces an approximation, since it assumes uniform velocity in the time interval between to PIV acquisitions. However the high temporal resolution achieved is beneficial for this integration, as the maximum displacement between two measurement times is about 2% of the device length scale.…”