Simulation of the Effects of Long-term Implantation of Biventricular Assist Device on the Hemodynamic Parameters in Heart Failure

Abstract

Background and Objectives:The ventricular assist device (VAD) was developed as a bridge to cardiac transplantation, but the current research trends are advancing the purpose of the bridge toward cardiac recovery. Using a simulation, we investigated the effects of long-term VAD implantation on the hemodynamic parameters related to the prognosis of heart failure so as to shed light on its preclinical and clinical applicability. Materials and Method:A moving-actuator type artificial heart developed by the Seoul National University Artificial Heart Laboratory was used as a model of the biventricular assist device. The initial values of the hemodynamic parameters were set according to the guidelines of VAD implantation. We then performed a simulation that tracks changes in the hemodynamic variables related to successful device weaning and the prognosis of heart failure. Results:Cardiac indices (CIs) at one hour and six months after VAD implantation were 2.98 l/min/m and 2.60 l/min/m, respectively. The systolic, diastolic and mean aorta pressures were 121, 84 and 99 mmHg six months after the VAD implantation. During the pump-off stage after six months, the hemodynamic parameters values were as follows:CI 2.53 l/min/m, pulmonary capillary wedge pressure 10 mmHg, left ventricular end-diastolic volume 105 ml, left ventricular ejection fraction 0.58, mean aorta pressure 84 mmHg, and end-systolic wall stress 108 kdyn/cm. The peak rate of change in power (peak dPWR(t)/dt) was 5.62×108 dyne·cm/s six months after the VAD implantation. In a real VAD-implanted patient, the simulation data were partly compatible with the real hemodynamic data, especially in the aspects of predicting VAD weaning. Conclusions:Long-term VAD implantation partially improved the values of the hemodynamic parameters related to prognosis, and these simulation results will provide the basic concept and applicability for the clinical trials of end-stage heart failure. (Korean Circulation J 2001;31(7):670-680)