MagScrew TAH - AN UPDATE

Abstract

Purpose: A passively filling, 45 ml stroke volume MagScrew Total Artificial Heart (TAH) system was tested in-vitro and in-vivo. Focus of the in-vitro experiments was the demonstration of preload and afterload sensitivity, atrial balance and flow capabilities. Goal of the in-vivo studies was the demonstration of blood/biocompatibility of all implanted system components and exercise tolerance on a treadmill. Methods: The in-vitro studies utilized a mock circulation, evaluating device performance in fixed rate and automatic control mode. The in-vivo experiments were conducted in calves. The TAH system was operated in automatic control mode. Results: In-vitro tests showed excellent preload sensitivity resulting in device flows above 10 L/Min at a beat rate of 220 BPM, at a systemic mean afterload of 100 mm Hg and a left atrial pressure of 13 mm Hg. Atrial balance was maintained at all tested conditions. Separate tests demonstrated low afterload sensitivity and a device flow of up to 14 L/min at beat rates of up to 280 BPM. Four in-vivo studies with durations between 4 - 83 days confirmed the in-vitro results with average flows ranging between 8.7 – 10.4 L/min at average beat rates ranging between 204 – 224 BPM. Hemodynamics remained normal with excellent left right atrial balance throughout the course of each experiment. Hemolysis was not detected in any animal. End-organ function was well maintained without thromoembolic events. The exercise tolerance of all animals was good, without signs of anaerobic metabolism.