Impeller Position in a Magnetically Levitated Rotodynamic Blood Pump and Its Impact on In-Silico Hemocompatibility

Area of Science:

• Biomedical Engineering
• Cardiovascular Devices
• Fluid Dynamics

Background:

• Impeller position in rotodynamic blood pumps (RPBs) is critical, influenced by electromagnetic and fluid forces.
• Understanding HeartMate 3 impeller dynamics is key for assessing hemocompatibility.

Purpose of the Study:

• To map the three-dimensional impeller position of the HeartMate 3 across various operating conditions.
• To evaluate the hemocompatibility implications of impeller displacement using computational fluid dynamics (CFD).

Main Methods:

• Utilized a transparent HeartMate 3 casing, laser distance measurements, and high-speed videography to capture impeller positions.
• Performed CFD simulations comparing displaced and centered impeller scenarios at a representative operating point.

Main Results:

• Impeller axial displacement reached 223 µm at 7 L/min and 7,000 rpm; radial displacement was up to 145 µm at 0 L/min and 7,000 rpm.
• CFD analysis showed impeller displacement caused <2% change in global pump parameters but up to 9% deviation in local flow metrics.

Conclusions:

• Impeller position in the HeartMate 3 varies considerably with operating parameters.
• Impeller displacement has a minor effect on overall pump performance but can influence local hemocompatibility, warranting further investigation.