LONG-TERM ENDURANCE OF GYRO CENTRIFUGAL BLOOD PUMP SYSTEM

Abstract

Purpose: Our group is developing a centrifugal blood pump as a long-term (>2-year) ventricular assist device. The pump consists of a ceramic shaft with ultra-high molecular weight polyethylene bearings located at the top and bottom of the pump housing. The pump impeller is magnetically-coupled to a DC motor actuator. Pump/actuator control is via an implantable control unit with transcutaneous energy transmission (TET) or an external wearable control unit. Methods: Eight pump/actuators are being operated in a LVAD mode. Each test station consists of a mock ventricle, an arterial compliance chamber, arterial resistor, and atrial filling chamber. Pumps are operated at 5 L/min with a outlet pressure of 100 mmHg. Six pump/actuators are controlled by three implantable units with TET and two pump/actuators are controlled by external controllers. The pump fluid is normal saline at 37o C. Results: As of January 17, 2006, the eight pump/actuators have test periods of 692 days (n=4), 683 days (n=1), 674 days (n=1), 573 days (n=1), and 434 days (n=1). Measured pump flows are 5.02 + 0.25 L/min at outflow pressure of 98 + 4 mmHg. Pump speed has averaged 1853 + 46 RPM with a power consumption of 0.28 + 0.03 amps and a system efficiency of 19.2 + 1.7%. Three implantable controllers with TET have test periods of 384, 354, and 344 days. The two external controllers have test periods of 180 days each. Conclusion: Thus far, the eight Gyro centrifugal blood pumps and actuators have accumulated 14.1 cumulative years of continuous in vitro testing without failure.