INITIAL ANIMAL EXPERIMENT OF A LINEAR OSCILLATORY ACTUATOR DRIVEN VENTRICULAR ASSIST SYSTEM

Abstract

The main purpose of this study is to develop an implantable direct electromagnetic left ventricular assist system (Linear-LVAS) with a linear oscillatory actuator (LOA). The Linear-LVAS is a pulsatile pump with a pusher-plate, which is driven directly by the mover of the LOA without any movement converter. The first model, developed in 2002, began its first animal experiment in 2003. The dimensions of the prototype Linear-LVAS are 100 mm in diameter, 50 mm in thickness, with a mass of 0.74 kg and a volume of 320 ml. The Linear-LVAS had two control algorithms: a fixed rate mode and a full-fill/full-eject mode (FFFE). Pump performance, long-term durability and nonthrombogenicity of Linear-LVAS was evaluated in a chronic animal experiment using a goat (56 kg). The goat survived for 42 days. The reason of termination of the experiment was the thrombus found in the pump. The maximum pump flow was around 4.2 L/min, with acceptable input power of 9 W. The maximum pump efficiency was 16.4%. Pump rate of Linear-LVAS driven by the FFFE control synchronized with goat’s heart rate. Pump housings and the diaphragm were free of major crack or deformation. Linear-LVAS had no troubles relating to the electronic control unit or the electronic drive line. There was no frictional dust found around the LOA in the pump unit. The experiment confirmed the durability of Linear-LVAS for 6 weeks.