A Numerical Study On Left Ventricular Hemodynamics Caused By BJUT Ⅱ With Diverse Blood Assist Index

The transplantation of left ventricular assisted device would change thehemodynamics of left ventricle, but the details keep unknown. The object of this paperis to clarify the hemodynamics effects with different Blood Assist Index (BAI) ofBJUT-II blood pump. The research are carried out as follows:To use the simulation software ADINA to simulate the behavior of left ventricle andits inner blood in healthy, heart failure and varies BAI of BJUT-II blood pump casesand then analyse the results.Based on the simulation results, some conclusions are made as follows:Firstly, the assistance of BJUT-II blood pump has changed the left ventricularpressure. The left ventricular pressure in BAI=20%and BAI=55%is higher than thatof heart failure case, while in BAI=75%,80%,95%case, the pressure is lower than thatof heart failure case, a higher BAI can produce a lower pressure, in short, a higher BAIcan help improve the unload of ventricle.Secondly, the assistance of BJUT-II blood pump has changed the blood flux. In fillingphase, the volume flow rate at mitral valve increased with the increased BAI, while inejecting phase, the volume flow rate at aortic valve decreased with increased BAI andthe duration of ejecting lengthened, which improved the organ perfusion jointly.Thirdly, the assistance of BJUT-II blood pump has changed the ventricular wall shearstress (WSS). The WSS decreased with the increased BAI, what’s more, there was noWSS distribution at apex region in high BAI cases.Fourthly, the assistance of BJUT-II blood pump has changed the ventricular flowpattern. In healthy case, two vortexes appeared at the inlet location, the upper vortexrotated clockwise and the lower one rotated counter clockwise, both the vortexesdeveloped with the flow jet and at the end of filling, the lower vortex became to thelargest form, besides, the vortex morphology could be maintained longer in healthy case,the vortex could reach to the apex and help to improve the blood movement, which washelpful to reduce the formation of thrombosis. In BAI=20%and BAI=55%cases, thereexisted two vortexes, and the lower one couldn’t move to the apex, leading to stagnantregion at apex, while in BAI=85%and95%cases, as the result of the outflow in aorticvalve, the upper vortex morphology was destroyed, and the vortex couldn’t move to theapex and leaded to stagnant region at apex. In the case of BAI=75%, the evolution oflower vortex was close to that of healthy case, the vortex could move to the apex at theend of filling phase, and it also could improve the blood movement at apex region.