Multiphase Hemodynamic Simulation On The Effect Of Assist Level Of Artificial Heart On Erythrocytes And Brain Blood Perfusion

Artificial heart is an effective clinical therapy to heart failure. But it is not clearthat hemodynamic effects on erythrocytes and brain blood purfusion under differentBlood Assist Index(). This paper aims to explore the effects of artificial heartunder different on blood inside the pump and blood supply to brain in order tosolve the following3problems：How is the time-frequency characteristic of bloodshear stress of artificial heart under different BAI? What are the effects of shear stressof artificial heart on erythrocytes? And how are the effects of artificial heart underdifferent on blood supply to brain?Firstly, the numerical simulation of multiphase of blood was conducted underdifferent (47%,62%,74%,82%), and the shear stress of erythrocytes wasextracted through the particle tracking. The time domain characters maximum andaverage value of the shear stress and the frequency domain characters the harmonicindex(HI), the, and were calculated and analyzed.Secondly, blood shear stress experiments were conducted to imitate the realisticfluid field of artificial heart acted on erythrocytes. Free hemoglobin of plasma wasmeasured and blood smears were made to count the number of abnormal erythrocytes.Finally, multiphase numerical simulation on blood supply to brain of artificialheart under cascade operation was conducted. Blood was considered as multiphasefluid of plasma and erythrocytes. Hemodynamic analysis was made for artificial heartto study the blood supply to brain under different. And animal experiments weredeveloped to have a further exploration of the blood supply to brain during artificialheart support.Three conclusions were obtained：First of all, the time domain characters maximum and average value of the shearstress increased with BAI. The amplitude of frequency components of shear stress hadno significant difference under different. The HI, the, andhad no difference with. The influences the time domain characters ofshear stress but not influences the distribution of frequency component of shear stress.Second of all, in vitro experimental results showed that after blood shearingexperiments the number of abnormal erythrocytes had increased with magnitude ofshear stress under constant exposure time(p=0.027<0.05), and abnormal erythrocytes had increased with amplitude of shear stress under constant same frequecy. Themagnitude and amplitude of shear stress influenced the number of abnormalerythrocytes.Last but not the least, numerical calculations showed that blood perfusion ofaorta and bifurcations increased with of the artificial heart, the left carotid arteryperfusion was slightly higher than right carotid arterial perfusion. Pulsation of leftsubclavian artery and the left common carotid artery reduced with the BAI increases.The volume fraction of erythrocyte changed small at the aortic arch and bifurcationaround45%. Erythrocyte volume fraction at blood pump impeller gap was greaterthan other part, up to60%. This area was also prone area of thrombosis. And animalexperimental results showed that with the increase speed, the average flow rate of leftand right carotid artery increase, flow rate of left carotid artery was greater than theright carotid artery flow and pulsation of left and right carotid artery reduced.