Fluid Dynamics in Rotary Piston Blood Pumps

Abstract

Mechanical circulatory support can maintain a sufficient blood circulation if the native heart is failing. The first implantable devices were displacement pumps with membranes. They were able to provide a sufficient blood flow, yet, were limited because of size and low durability. Rotary pumps have resolved these technical drawbacks, enabled a growing number of mechanical circulatory support therapy and a safer application. However, clinical complications like gastrointestinal bleeding, aortic insufficiency, thromboembolic complications, and impaired renal function are observed with their application. This is traced back to their working principle with attenuated or non-pulsatile flow and high shear stress. Rotary piston pumps potentially merge the benefits of available pump types and seem to avoid their complications. However, a profound assessment and their development requires the knowledge of the flow characteristics. This study aimed at their investigation. A functional model was manufactured and investigated with particle image velocimetry. Furthermore, a fluid-structure interaction computational simulation was established to extend the laboratory capabilities. The numerical results precisely converged with the laboratory measurements. Thus, the in silico model enabled the investigation of relevant areas like gap flows that were hardly feasible with laboratory means. Moreover, an economic method for the investigation of design variations was established.

Numerical Approach to Study the Behavior of an Artificial Ventricle: Fluid–Structure Interaction Followed By Fluid Dynamics With Moving Boundaries

“…Recent works on VADs showed a relative fluid volume with shear stress above the threshold of 150 Pa comparable with our results. Moreover, in the validation work of Wappenschmidt et al , the goodness of the FSI methodology to calculate this hemolysis indexes was verified. In vivo analysis in calves confirmed that the Carmat‐TAH maintains the hemodynamic parameters in an acceptable range with no signs of coagulation activation .…”

“…Nascimbene et al (12) proved the strictly relation between shear stress and hemolysis. Recent works (36,37) on VADs showed a relative fluid volume with shear stress above the threshold of 150 Pa comparable with our results. Moreover, in the validation work of Wappenschmidt et al (36), the goodness of the FSI methodology to calculate this hemolysis indexes was verified.…”

Comparison of fluid flow between bimanual and coaxial phacoemulsification using computational fluid dynamics

“…Computational fluid dynamics is a sub-discipline of fluid mechanics that deals with fluid flow and allows for the simulation of complex fluid systems. It has been applied to various biomedical systems, such as those involved in heart pumping, [15] cardiac valve design, [16] blood flow analysis, [17] vessel graft evaluation, [18] nose or sinus flow analysis, [19] and lung airflow analysis.…”

Spherical Gerotor: Synthesis of a Novel Valveless Pulsatile Flow Spherical Total Artificial Heart

“…Two recent designs are interesting and deserve more research. A rotary piston blood pump, adopting the architecture of a vehicle rotary engine, combines the benefits of membrane pump and rotary pump [26]. Another one, which is similar to our concept, is a spherical shape TAH with four chambers divided by two rotating disks [27].…”

“…The assumption is solid once the wedge modified distance is small and tilt angle is not too big. Noting that the volume of each chamber at every position is a portion of the whole sphere, the volume can be expressed as (26) Spherical Gerotor: Synthesis of a Novel Valveless Pulsatile Flow Spherical Total Artificial Heart 288 where is the radius of the middle sphere which contains the gear set.…”