In vivo experiment leading to clinical application of an electrohydraulic ventricular assist device with magnetic coupling

We developed an electrohydraulic ventricular assist device with magnetic co upling. The integrated system consists of a blood pump, a water conduit for pressure transmission, a. bellows type pumping sac, an actuator for transf orming the circular motion of a motor to the linear motion of a pusher plat e attached to the pumping sac with magnetic coupling, and a controller. The purpose of the coupling was to prevent excessive sucking against the atria l wall. Number 21 Medtronic Hall (Irvine, CA) mechanical valves were used i n the inflow and outflow ports of the blood pump. Maximum dynamic stroke vo lume was 48 mi, and against a mean after-load of 100 mm Hg, maximum pump ou tput was 7 L/min. Chronic in vivo experiments were performed in three sheep , and during these evaluations the system showed no noticeable problems rel ated to mechanical or electronic devices. When left atrial pressure decreas ed below 0 mm Hg, the magnetic coupling system decoupled the pumping sac an d pusher plate with satisfactory reliability. The device was clinically app lied in a postoperative patient with chronic dilating cardiomyopathy, and n o significant device related problems ensued. These results prove that the electrohydraulic ventricular assist system with magnetic coupling is a suit able ventricular assist device.