Technologies
Minimally Invasive VAD (MIVAD)
Design Process
At such small geometries for macro-sized machines, and with the potential interaction and dependence of system parameters on each other, a computer-based modeling approach has been used to evaluate alternate topologies for a pump this small. This computer-based multi-disciplinary optimization design process has been used effectively in the PediaFlow VAD and Levacor VAD development process.
This computer-based model incorporates design parameters for key subsystems such as the pump, the motor, the magnetic levitation, power consumption as well as experiential learning and mathematical models for blood damage.
Once the output of this process provides a first-cut estimate of the design architecture of, and optimal topology for the system, detailed engineering analyses are performed to finalize the design details.
The figure above depicts this process for the first prototype of the PediaFlow VAD. From bottom right, once the motor and magnetic suspension topology is selected, detailed computer-based engineering analyses were done to finalize the design. These included (clockwise from bottom right figure left of center):
- Structural FEA (Finite Element Analysis).
- Electromagnetic FEA.
- Heat Transfer modeling.
- Computational Fluid Dynamics (CFD) optimization of flows to finalize pump and blading geometry.
- Verification of CFD results with flow visualization and Particle Imaging Velocimetry (PIV).
- Anatomical modeling to assure anatomic fit of designed pump configuration into CT scans of prospective patients.
- Development of assays to test sub-lethal indicators of blood compatibility.
- Development of a pediatric mock loop to test hemodynamics of the rotary pump supporting a pulsatile natural heart.