Chronic animal experiment with magnetically suspended centrifugal pump

Area of Science:

• Biomedical Engineering
• Cardiovascular Research
• Medical Device Development

Background:

• Ventricular assist devices (VADs) are crucial for managing heart failure.
• Existing VADs often face limitations in longevity due to mechanical wear and thrombosis.
• A novel pump design is needed to overcome these challenges for long-term patient support.

Purpose of the Study:

• To evaluate the long-term performance and durability of a novel magnetically suspended centrifugal pump (MSCP).
• To assess the MSCP's efficacy in a paracorporeal left ventricular assist circulation model in sheep.
• To compare different driving modes for optimizing pump performance and stability.

Main Methods:

• Development and implantation of a paracorporeal MSCP in a sheep model.
• Establishing left ventricular assist circulation between the left atrium and descending aorta.
• Testing flow rates from 2.5-5.5 L/min and monitoring animal survival.
• Analyzing plasma free hemoglobin for hemolysis assessment and comparing pump performance under constant motor current vs. constant rotational speed modes.

Main Results:

• The MSCP demonstrated durability for over 46 days in a sheep model.
• The longest-surviving sheep (46 days) experienced an embolism due to thrombus formation in the pump; other pumps showed no thrombus.
• Plasma free hemoglobin levels remained within an acceptable range (9-18 mg/dl), indicating minimal hemolysis.
• Constant motor current mode resulted in a steeper pressure-flow relationship and reduced flow fluctuation compared to constant rotational speed mode.

Conclusions:

• The magnetically suspended centrifugal pump (MSCP) shows significant promise as a durable device for long-term ventricular assist.
• Further development is needed to mitigate the risk of thrombus formation for enhanced long-term reliability.
• The MSCP's performance characteristics suggest its potential as a next-generation cardiac support technology.