Effects of pulmonary afterload on the hemodynamics after the hemi-Fontan procedure

A computational fluid dynamics study based on the application of the finite volume method has been performed to investigate the effects of the pulmona ry afterload on the hemodynamics after the hemi-Fontan procedure. This oper ation is generally used as part of a series of staged procedures to treat c omplex congenital malformations of the heart. It consists of re-directing t he superior vena caval flow from the right atrium into the pulmonary arteri es, by-passing the right ventricle while excluding the inferior caval flow from the lungs. To reproduce correctly the pulmonary afterload conditions, a simplified lumped-parameter mechanical model of the pulmonary circulation has been developed and linked to the finite volume solver. In addition, th e effect of a stenosis in the left pulmonary artery was also examined. In t his paper the adopted methodology is presented, together with some of the p reliminary results. The model has been used to simulate the local fluid dyn amics for different values of the pulmonary arteriolar resistance and lung resistances, allowing a quantitative evaluation of the dissipated energy an d the flow distribution into the lungs. The results show that both flow dis tribution into the lungs and energy dissipation after the hemi-Fontan proce dure are only minimally affected by the pulmonary arteriolar resistance. (C ) 2001 IPEM. Published by Elsevier Science Ltd. All rights reserved.