What is the clinical evidence from this study?

Study design: Other. Population: Heart failure (computational model). Intervention: Pulsatile LVAD in counter-pulsation mode vs. Co-pulsation and continuous flow modes. Primary outcome: Peak left ventricular pressure (mmHg).

April 22, 2009Open Access

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

KLKi Moo LimKumoh National Institute of Technology IKIn Su KimChungbuk National University SCSeong Wook ChoiKangwon National University

Key Result

In a computational model of heart failure, a pulsatile left ventricular assist device in counter-pulsation mode provided the highest coronary perfusion and lowest peak left ventricular pressure.

Structured PICO

Does a pulsatile LVAD with counter-pulsation mode improve coronary perfusion and reduce ventricular afterload compared to co-pulsation or continuous flow modes in a computational heart failure model?

Population

A 16-compartment computational cardiovascular system model simulating heart failure (implemented by decreasing end-systolic elastance to 40% of normal and blocking the control path of cardiac contractility).

Intervention

Pulsatile left ventricular assist device (LVAD) operating in counter-pulsation mode (mean flow rate 5,000 ml/min).

Comparator

Pulsatile LVAD operating in co-pulsation mode and LVAD operating in continuous flow mode (mean flow rate 5,000 ml/min).

Outcome

Coronary blood perfusion and peak pressure of the left ventricle (ventricular afterload).surrogate

In a computational model of heart failure, a pulsatile LVAD operating in counter-pulsation mode provided superior coronary perfusion and greater reduction in ventricular afterload compared to continuous flow or co-pulsation modes.

Main Result

Absolute Event Rate: 43% vs 51%

Limitations

Omitted right coronary flow for simplification
Results are based on a computational simulation rather than in vivo or clinical data

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.

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