An Electromechanical (Solenoid) Energy Converter and Control System for a Clinical Left Ventricular Assist System

摘要

Development of a solenoid-actuated Left Ventricular Assist System (LVAS) was carried through three major design iterations (MK19, MK20, MK22). The MK22 energy converter was the first designed specifically from a systems approach, to be integrated with the Andros dual pusher-plate blood pump. Analytical models were developed for solenoid design and analysis. A microprocessor-based Electronic Control and Power (ECP) subsystem provided flexible and reliable operation. Extensive characterization and endurance testing were conducted in vitro and in vivo at each stage of development. Four energy converters operated without failure for periods ranging from 1.2 to 1.5 years. The MK22 LVAS demonstrated solenoid efficiencies of 70 to 80% and energy converter efficiencies averaging 50% over a range of pump outputs from 2 to 12 L/min and a range of systemic pressures from 90 to 150 torr. Synchronous operation with excellent responsiveness has been achieved at rates to 180 beats/min. During this period, the LVAS was evaluated in 27 acute and 36 chronic in vivo experiments with synchronous pumping extending over 100 days in three animals (longest over 5 months).