Numerical simulation of pulse wave propagation and parameter analysis based on transmission line model / 医用生物力学

Objective To numerically simulate the propagation of pulse wave in human arterial tree by proposing a novel calculation method which combines a transmission line model and a recursive algorithm of input impedance, and to study the effects of individual differences and arterial tree parameters on pulse wave so as to provide references for the analysis on physiologic and pathologic characteristics of human arterial tree. MethodsThe transmission line model of human arterial tree was constructed, which consisted of 55-segment large and medium sized arteries. The recursive algorithm was applied to compute the input impedance of arterial tree at each point. The blood pressures and flows of 55 arteries were calculated and showed in the distribution graphs. Based on this method, the effects of height, heart rate, stroke volume, internal radius and wall thickness on pulse wave propagation and blood pressure distribution were compared. Results The simulation results were in good agreement with the general rules of pulse wave propagation. The propagation of pulse wave in arterial tree showed significantly different characteristics for different parameters. Conclusions The proposed method can effectively simulate the propagation of pulse wave in arterial tree and accurately reflect the effects of individual differences and hemodynamics parameters on pulse wave propagation, and it is an important assistant means for the pathophysiologic analysis and diagnosis of human arterial tree.

Recursive calculation and parameter analysis on input impedance of arterial tree based on electric network model / 医用生物力学

Objective In order to provide a reference for analysis of the pathophysiological changes of human arterial tree, the effects of the arterial parameters on input impedance of arterial tree were studied by proposing a recursive algorithm to calculate the input impedance. Method A distributed electric network model was constructed for the arterial tree which consisted of 55 segments accounting for all the central vessels and major peripheral arteries. By setting up the peripheral resistance of the model and constructing a unilateral data link list of the arterial tree, the recursive algorithm was employed to compute the input impedance of ascending aorta in the arterial tree. Then, comparisons of the effects of arterial compliance, peripheral resistance, length, internal radius and wall thickness on the input impedance were made based on the recursive algorithm. Results The computational results were in accord with experimental data and results of other models, and proved the validity of the model and algorithm. The input impedances of the arterial tree showed significant influence with different characteristics for different parameters. Conclusions The input impedance of arterial tree can reflect the changes of the hemodynamic parameters effectively, which is an important reference for the pathophysiological diagnosis of human arterial tree.