A Validated Computational Fluid Dynamics Model to Estimate Hemolysis in a Rotary Blood Pump

Abstract

A major part of developing rotary blood pumps requires the optimization of hemolytic properties of the entire pump. Application of a suited computational fluid dynamics (CFD)-based hemolysis model allows approximation of blood damage in an early phase of the design process. Thus, a drastic reduction of time- and cost- intensive hemolysis experiments can be achieved. For the MicroDiagonal Pump (MDP), still under development at Helmholtz-Institute in Aachen, Germany, different pump configurations have been analyzed, both numerically and experimentally. The CFD model of the pump has been successfully validated based on the comparison of the pressure head curves (H-Q curves), as discussed in a prior publication. In the present study, the authors focus on the development of a semiempiric blood damage model using the CFD and in vitro hemolysis data. On the one hand, mean key characteristics (shear stress and exposure time) and other characteristics affecting blood damage have been calculated based on numerical data. On the other hand, in vitro hemolysis tests have been accomplished in order to determine the hemolytic curves of two different pump configurations (with the same impeller but different tip clearances). Finally, a new function based on a general power law has been defined by means of the mean key characteristics. The unknown constants of the function have been determined by multidimensional regression analysis using the hemolytic curves. For the final validation of this new blood damage model, the calculated and the in vitro obtained hemolysis indices at the specific VAD operating point have been compared for all pump configurations. The comparison showed an excellent agreement, both qualitatively and quantitatively.

Numerical Simulation of LVAD Inflow Cannulas with Different Tip

“…The hemolysis in the inflow cannulas is mainly caused by the high shear stress of flow in the inflow cannulas. The effective numerical prediction of mechanical hemolysis has been built [13][14][15]. In vitro and in vivo mechanical hemolysis tests have been studied previously [16][17][18].…”

Evaluation of the Effect of Needle Tilting Angle on Irrigant Flow in the Root Canal Using Side-Vented Needle by an Unsteady Computational Fluid Dynamics Model

“…Computational Fluid Dynamics (CFD) is a powerful technique to simulate the fluid flow based on finite volume approximations of Navier-Stokes (i.e., governing fluid flow) equations (9)(10)(11). Due to its convenience, CFD model was recently introduced for the evaluation of irrigant flow in the root canal (12).…”

Computational fluid dynamics analysis and PIV validation of a bionic vortex flow pulsatile LVAD

“…Despite the recent trend towards continuous-flow LVADs, patients with pulsatile-flow LVADs have a higher chance of myocardial recovery, surplus hemodynamic energy, and demonstrate improved renal function, improved blood flow of the vital organs and a lower rate of gastrointestinal bleeding events [5][6][7][8][9]. However, pulsatile blood pumps suffer from design concerns which consist of poor reliability, decreased biocompatibility, inefficient hydraulic performance at small dimensions and the increased risk of thrombosis and hemolysis [10][11][12]. These challenges are mainly related to the flow states within the blood chamber which have been investigated extensively in the development of LVADs.…”