Computational analysis of the effect of the type of LVAD flow on coronary perfusion and ventricular afterload

Abstract

We developed a computational model to investigate the hemodynamic effects of a pulsatile left ventricular assist device (LVAD) on the cardiovascular system. The model consisted of 16 compartments for the cardiovascular system, including coronary circulation and LVAD, and autonomic nervous system control. A failed heart was modeled by decreasing the end-systolic elastance of the ventricle and blocking the mechanism controlling heart contractility. We assessed the physiological effect of the LVAD on the cardiovascular system for three types of LVAD flow: co-pulsation, counter-pulsation, and continuous flow modes. The results indicated that the pulsatile LVAD with counter-pulsation mode gave the most physiological coronary blood perfusion. In addition, the counter-pulsation mode resulted in a lower peak pressure of the left ventricle than the other modes, aiding cardiac recovery by reducing the ventricular afterload. In conclusion, these results indicate that, from the perspective of cardiovascular physiology, a pulsatile LVAD with counter-pulsation operation is a plausible alternative to the existing LVAD with continuous flow mode.

Mathematical analysis of the effects of valvular regurgitation on the pumping efficacy of continuous and pulsatile left ventricular assist devices

“…We used a lumped parameter model of the cardiovascular system based on the Windkessel element and the heart was modeled using the concept of time-varying compliance 17 . In order to reduce modeling complexity, we did not implement the coronary circulation and nervous short-term regulation of the cardiovascular system which are implemented in our previous paper 15 . That is because the only short-term blood pressure regulation by the nervous system without other long-term regulation would not give us significant insight.…”

“…This is an equation for the internal pressure and volume of the pulsating heart. Several previous cardiovascular hemodynamic studies simulated the heart using this time-varying compliance concept 15, 18, 19Fig.…”

“…As an alternative, computational methods can be applied. We have performed several studies comparing ventricular unloading effects under different pumping types14, 15 and cannulation sites 16 using computational methods.…”

Computational analysis of the effect of valvular regurgitation on ventricular mechanics using a 3D electromechanics model

“…The detailed investigation of ventricular mechanics under regurgitation conditions presented here was made possible by the use of a 3D ventricular model [4], a significant advance over previous lumped-parameter and one-dimensional models of the cardiovascular system [16]. Since the mechanical response evoked by LV volume overload or underload in valvular regurgitation can lead to ventricular remodeling and HF, understanding the changes in ventricular mechanics in the presence of regurgitant flow could have important clinical implications.…”

Computational Analysis of Pumping Efficacy of a Left Ventricular Assist Device according to Cannulation Site in Heart Failure with Valvular Regurgitation

“…Using a computational method similar to the numerical method used for developing previously reported cardiac electromechanical models [12, 13], we simulated a failing canine ventricular model under the following three conditions: HF without valvular regurgitation (normal), HF with 5% AR, and HF with 5% MR. We applied these conditions to the following three groups based on the LVAD cannulation site: control, LAAO, and LVAO. In the control group, the conditions (normal, AR, and MR) were modeled without the use of the LVAD.…”