Pulsatile impeller heart: a viable alternative to a problematic diaphragm heart

Area of Science:

• Biomedical Engineering
• Cardiovascular Devices
• Hemodynamics

Background:

• Impeller blood pumps offer simplicity but lack pulsatility, limiting their clinical use.
• Previous attempts to create pulsatile impeller pumps often resulted in significant hemolysis.
• Diaphragm pumps are pulsatile but more complex than impeller designs.

Purpose of the Study:

• To develop a pulsatile impeller blood pump that minimizes hemolysis.
• To investigate the efficacy of a streamlined impeller design for producing pulsatile blood flow.
• To evaluate the biocompatibility and performance of the novel pump in acute and chronic settings.

Main Methods:

• A centrifugal pump with a streamlined impeller featuring coincident vane and shroud surfaces was designed.
• Pulsatility was induced by periodically varying the motor's rotating speed using a square wave voltage.
• In vitro hemolysis testing and in vivo left ventricular assist experiments in calves and biventricular assist in pigs were conducted.

Main Results:

• The pulsatile impeller pump demonstrated a lower hemolysis index compared to other pulsatile pumps.
• In vitro testing showed a slightly higher hemolysis index than the nonpulsatile version but acceptable levels.
• In vivo studies in calves (up to 11 days) and pigs showed no blood damage, with normal hematological and biochemical parameters.

Conclusions:

• The streamlined impeller design effectively produces pulsatile blood flow with reduced hemolysis.
• The developed pulsatile impeller pump is biocompatible and suitable for cardiac assistance.
• A biventricular assist device utilizing two such pumps demonstrated effective and safe biventricular support.