title: Interaction of a Transapical Miniaturized Ventricular Assist Device With the Left Ventricle: Hemodynamic Evaluation and Visualization in an Isolated Heart Setup.
abstract: New left ventricular assist devices (LVADs) offer both important advantages and potential hazards. VAD development requires better and expeditious ways to identify these advantages and hazards. We validated in an isolated working heart the hemodynamic performance of an intraventricular LVAD and investigated how its outflow cannula interacted with the aortic valve. Hearts from six pigs were explanted and connected to an isolated working heart setup. A miniaturized LVAD was implanted within the left ventricle (tMVAD, HeartWare Inc., Miami Lakes, FL, USA). In four experiments blood was used to investigate hemodynamics under various loading conditions. In two experiments crystalloid perfusate was used, allowing visualization of the outflow cannula within the aortic valve. In all hearts the transapical miniaturized ventricular assist device (tMVAD) implantation was successful. In the blood experiments hemodynamics similar to those observed clinically were achieved. Pump speeds ranged from 9 to 22 krpm with a maximum of 7.6 L/min against a pressure difference between ventricle and aorta of ∼50 mm Hg. With crystalloid perfusate, central positioning of the outflow cannula in the aortic root was observed during full and partial support. With decreasing aortic pressures the cannula tended to drift toward the aortic root wall. The tMVAD could unload the ventricle similarly to LVADs under conventional cannulation. Aortic pressure influenced central positioning of the outflow cannula in the aortic root. The isolated heart is a simple, accessible evaluation platform unaffected by complex reactions within a whole, living animal. This platform allowed detection and visualization of potential hazards.
authors.affiliation: Center for Medical Physics and Biomedical Engineering, Medical University of Vienna.|Ludwig Boltzmann Cluster for Cardiovascular Research.
authors.forename: Marcus
authors.initials: M
authors.lastname: Granegger
authors.affiliation: Center for Medical Physics and Biomedical Engineering, Medical University of Vienna.|Ludwig Boltzmann Cluster for Cardiovascular Research.
authors.forename: Philipp
authors.initials: P
authors.lastname: Aigner
authors.affiliation: Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Haberl
authors.affiliation: Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria.
authors.forename: Stephane
authors.initials: S
authors.lastname: Mahr
authors.affiliation: HeartWare Inc, Miami Lakes, FL, USA.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Tamez
authors.affiliation: HeartWare Inc, Miami Lakes, FL, USA.
authors.forename: Joel
authors.initials: J
authors.lastname: Graham
authors.affiliation: HeartWare Inc, Miami Lakes, FL, USA.
authors.forename: Nathalie J
authors.initials: NJ
authors.lastname: Nunez
authors.affiliation: Center for Medical Physics and Biomedical Engineering, Medical University of Vienna.|Ludwig Boltzmann Cluster for Cardiovascular Research.|Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria.
authors.forename: Heinrich
authors.initials: H
authors.lastname: Schima
authors.affiliation: Center for Medical Physics and Biomedical Engineering, Medical University of Vienna.|Ludwig Boltzmann Cluster for Cardiovascular Research.
authors.forename: Francesco
authors.initials: F
authors.lastname: Moscato
mesh_terms: D000818:Animals; D001021:Aortic Valve / Q000503:physiopathology*; D006352:Heart Ventricles / Q000503:physiopathology* / Q000601:surgery*; D006353:Heart-Assist Devices; D006439:Hemodynamics; D008904:Miniaturization; D011474:Prosthesis Design; D019919:Prosthesis Implantation; D013552:Swine; D016277:Ventricular Function, Left
keywords: Cannula-heart valve interaction; Ex vivo cardiac model; Intraventricular left ventricular assist device