Computational analysis of the importance of flow synchrony for cardiac ventricular assist devices.
This paper presents a patient customised fluid-solid mechanics model of the left ventricle (LV) supported by a left ventricular assist device (LVAD). Six simulations were conducted across a range of LVAD flow protocols (constant flow, sinusoidal in-sync and sinusoidal counter-sync with respect to the cardiac cycle) at two different LVAD flow rates selected so that the aortic valve would either open (60mLs(-1)) or remain shut (80mLs(-1)). The simulation results indicate that varying LVAD flow in-sync with the cardiac cycle improves both myocardial unloading and the residence times of blood in the left ventricle. In the simulations, increasing LVAD flow during myocardial contraction and decreasing it during diastole improved the mixing of blood in the LV cavity. Additionally, this flow protocol had the effect of partly homogenising work across the myocardium when the aortic valve did not open, reducing myocardial stress and thereby improving unloading.
Department of Computer Science, University of Oxford, Wolfson Building, Parks Road, OX1 3QD, UK.
Matthew
M
McCormick
Department of Biomedical Engineering, King׳s College London, The Rayne Institute, 4th Floor Lambeth Wing, St Thomas׳ Hospital, SE1 7EH, UK.
David
D
Nordsletten
Department of Biomedical Engineering, King׳s College London, The Rayne Institute, 4th Floor Lambeth Wing, St Thomas׳ Hospital, SE1 7EH, UK.
Pablo
P
Lamata
Department of Computer Science, University of Oxford, Wolfson Building, Parks Road, OX1 3QD, UK; Department of Biomedical Engineering, King׳s College London, The Rayne Institute, 4th Floor Lambeth Wing, St Thomas׳ Hospital, SE1 7EH, UK; Faculty of Engineering, University of Auckland, 20 Symonds St, Auckland, New Zealand. Electronic address: np.smith@auckland.ac.nz.
Nicolas P
NP
Smith
D001696:Biomechanical Phenomena; D003198:Computer Simulation; D006321:Heart / Q000033:anatomy & histology / Q000502:physiology; D006352:Heart Ventricles / Q000033:anatomy & histology*; D006353:Heart-Assist Devices; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008875:Middle Aged; D008955:Models, Cardiovascular; D009200:Myocardial Contraction / Q000502:physiology*; D016277:Ventricular Function, Left / Q000502:physiology*
Cardiovascular; Computational model; Computer model; Fluid–structure; Tissue mechanics