title: In vitro controllability of the MagScrew total artificial heart system.
abstract: The purpose of this study was to evaluate the in vitro responses to preload and afterload of our total artificial heart (TAH), the MagScrew TAH. The TAH consists of two blood pumps and a control logic, developed at the Cleveland Clinic, OH, and the MagScrew actuator and its electronic control system, developed by Foster-Miller Technologies, Inc., Albany, NY. Tests were performed on a mock circulatory loop, using water as a test fluid. Preload sensitivity of the Mag-Screw TAH demonstrated a Frank-Starling response to preload in automatic mode. A peak flow of 10 L/min was obtained, with a left atrial pressure of 13 mm Hg. The relationship between right atrial pressure and left atrial pressure was well balanced when tested with a left bronchial shunt flow of 5% and a range of pulmonary artery and aortic pressures. With respect to afterload response, the left pump showed a relatively low sensitivity, which allowed the pump to maintain perfusion over a wide range of aortic pressures. The right pump, on the other hand, was much more sensitive to pulmonary artery pressure, which provided a measure of protection against pulmonary congestion. The very effective physiologic response of the MagScrew TAH is believed to result from employment of a left master, alternating ejection control logic, high inherent sensitivity of the blood pumps to atrial pressure, a lower effective stroke volume for the right pump, and a scaling of right side motor ejection voltage to 80% of that used for the left side ejection.
authors.affiliation: Department of Biomedical Engineering, Cleveland Clinic Foundation, Ohio 44195, USA.
authors.forename: Stephan
authors.initials: S
authors.lastname: Weber
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Doi
authors.forename: Alex L
authors.initials: AL
authors.lastname: Massiello
authors.forename: Bryan P
authors.initials: BP
authors.lastname: Byerman
authors.forename: Masami
authors.initials: M
authors.lastname: Takagaki
authors.forename: Kiyotaka
authors.initials: K
authors.lastname: Fukamachi
authors.forename: Arthur
authors.initials: A
authors.lastname: Donahue
authors.forename: Peter
authors.initials: P
authors.lastname: Chapman
authors.forename: Gordon
authors.initials: G
authors.lastname: Hirschman
authors.forename: Nicolas
authors.initials: N
authors.lastname: Vitale
authors.forename: William A
authors.initials: WA
authors.lastname: Smith
mesh_terms: D001011:Aorta / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D006321:Heart / Q000502:physiology*; D006325:Heart Atria; D006354:Heart, Artificial; D066298:In Vitro Techniques; D011474:Prosthesis Design; D011651:Pulmonary Artery / Q000502:physiology; D013318:Stroke Volume / Q000502:physiology; D014690:Venous Pressure / Q000502:physiology