Simulation of arterial hemodynamics after partial prosthetic replacement of the aorta

Background. Replacing parts of the aorta with a noncompliant: vascular pros thesis results in marked alterations of the aortic input impedance and infl uences arterial hemodynamics. We propose a mathematical model of: circulati on that can predict hemodynamic changes after simulation of vascular grafti ng. Methods. A new mathematical model of the human arterial system was develope d on a 75-MHz Pentium personal computer using Matlab software. The human ar terial tree was delineated according to a 128-branch design encompassing bi furcations and physical properties of the arterial wall. A digitized aortic flow wave was chosen as the input signal to the system. After determinatio n of the modules of elasticity of native vascular tissue and standard prost heses in technical experiments, replacement of any part of the aorta with a prosthesis was simulated by increasing the elasticity in the parts desired . Results. During control conditions, the model displayed a physiologic distr ibution of flow and pressure waves throughout the arterial system. Simulate d replacement of the aorta resulted in an increase in pressure amplitude an d a partial loss of the aortic "Windkessel" function. Calculation of the ao rtic input impedance showed an increase in the characteristic impedance, wh ereas the peripheral resistance remained unaltered. Conclusions. This mathematical model of the arterial circulation is useful for simulating hemodynamic changes after implantation of vascular grafts. T he results of the model analysis are consistent with those in previous expe rimental work. (Ann Thorac Surg 1999;67:676-82) (C) 1999 by The Society of Thoracic Surgeons.