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ASAIO CARDIAC ABSTRACT

DEVELOPMENT OF THE DIRECT ELECTROMAGNETIC VENTRICULAR ASSIST DEVICE: FIRST TRIAL ON EX VITRO EVALUATION

Fukunaga, K1; Hornma, A2; Funakubo, A1; Sumikura, H1; Onuma, K1; Oshikawa, M2; Naito, Y2; Tatsumi, E2; Taenaka, Y2; Kitamura, S2; Fukui, Y1

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The main purpose of this study is to develop an implantable direct electromagnetic left ventricular assist system (DEM-LVAS) with a linear oscillatory actuator (LOA). The DEM-LVAS is a pulsatile pump with a pusher-plate, which is driven directly by the mover of the LOA without any movement converter such as a roller screw or a hydraulic system. The first model, developed in 2002, began its first ex vivo study in December 2003. This report covers recent progress in the development of the DEM-LVAS, focusing on ex vivo evaluation of the prototype. The DEM-LVAS was 101 mm in diameter, 49 mm in length, 320 ml in volume and weighs 770 g. The DEM-LVAS had two control algorithms: a fixed rate mode and a full-fill/full-eject mode (FFFE). An in vitro test demonstrated over 8 L/min maximum output at 200 bpm and the maximum pump efficiency exceeded 16%. The long-term durability and nonthrombogenicity of the DEM-LVAS was evaluated in a chronic goat left heart bypass model (56 kg). The maximum bypass output was around 4.2 L/min, with acceptable input power of 9 W. The maximum pump efficiency reached 14%. The heart rate of the goat was 100 to 160 bpm. The FFFE operation of the DEM-LVAS successfully followed the heart rate of the goat, driving at the same rate as the natural heart. Plasma free hemoglobin and hepatic function remained in the normal range throughout the experiment. The goat has survived for more than 1 month without major complications, and the study is being continued.

Copyright © 2004 by the American Society for Artificial Internal Organs