Study of the energy efficiency of various drive systems of an innovative implantable left ventricular assist device.

This paper presents the results of studies of the energy efficiency of an innovative implantable left ventricular assist device. One of the advantages of the proposed LVAD is in cases where end-stage left ventricular failure is accompanied by mitral valve regurgitation and pulmonary hypertension. Another advantage is minimally invasive implantation with minimal thoracic trauma, without disrupting the breathing process, which shortens the length of hospital stay. The best drive system for converting the rotary motion of the servo motor into reciprocating motion of the piston of the suction-discharge device was chosen. Two types of drive were considered, namely a yoke mechanism and a crank mechanism that were evaluated in terms of energy efficiency of the entire device. One of the most important conclusions is that both mechanisms have comparable operating parameters for balloon inflation and similar electrical energy consumption which amounts to comparable operating times for these mechanisms. However, the energy consumption of the yoke mechanism is slightly higher. At the same time the pressure in the left ventricle and aorta is slightly lower in comparison with a yoke mechanism. Furthermore, the results of the study also showed that the balloon pressures were significantly higher with crank drive, which may cause the balloons to wear out more quickly. The mass flow rates generated by both drives are similar with a slight advantage for the yoke mechanism. Finally, typical aortic, atrial and left ventricular pressure plots during the cardiac cycle are also shown.