Numerical simulations and experiments on changes in erythrocyte morphology under continue flow ventricular assisted devices

摘要

Ventricular assist devices (VADs) implanted in human body produce different levels of shear stress due to mechanical structure, causing damage for erythrocytes. The study is focusing on the morphology changes of erythrocytes causing by continue flow VADs. This study used a Hemodynamic Shearing Device (Thermo Electron Corporation) to expose erythrocytes to shear stress produced by VADs. Then free hemoglobin of plasma is measured and blood smears are respectively made to count the number of abnormal erythrocytes. The results show that the correlation coefficient of the percent of abnormal erythrocytes (PAE) and shear stress is 0.725 (p=0.027, <0.05). After blood shearing experiments the number of abnormal erythrocytes has increased with shear stress under constant exposure time, and both shear stress and exposure time contribute to morphology changes in erythrocytes. The conclusion indicates that low shear stress (lower than 450 Dynes/cm~2) damage of erythrocyte is an important factor in the application of VADs.