Acute hemodynamic study of Tai-Ta left ventricular assist device in a canine model

A revised Tai-Ta centrifugal impeller pump was designed to study the interaction of the left ventricular assist device (LVAD) with the cardiovascular system in a canine model. Six healthy dogs weighing 12-16 kg were used. Blood flows in the aortic arch, the pulmonary artery (PA), and the LVAD outlet were measured simultaneously with the arterial blood pressure (ABP), the pump outflow pressure (POP), and the electrocardiograph (ECG). Normally, the blood flows in the aorta and the PA started at the S-wave of the ECG. When the LVAD was operated at a higher rotational speed (increased from 2900 to 5400 rpm), the ABP, POP, the pump flow, and the maximum rate of change of PA flow increased. However, the fluctuating amplitudes of ABP, POP, and the pump flow decreased significantly. The cardiovascular hemodynamics change with the pump speeds. For a typical 1.1-1.5 L/min cardiac output in canine, the revised LVAD was able to deliver a flow bypass ratio from 15% up to 100%. The LVAD outflow appeared to be pulsatile and matched the cardiac cycle, showing that the centrifugal impeller pump could be used as a pediatric assist device when cardiac function was impeded.