Computational fluid dynamic simulations of cavopulmonary connections with an extracardiac lateral conduit

Complex congenital heart defects due to the absence of a ventricular chambe r can often be treated by the Fontan surgical procedure. The objective of t his work was to quantify the haemodynamics in the Fontan operation (cavopul monary connection) with extracardiac lateral conduit. Four different models based on the finite element method were constructed with different lengths of inferior anastomosis (range 18-25 mm) and inclinations of the conduit ( 33 and 47.5 degrees). Mass conservation and Navier-Stokes equations were so lved by means of the FIDAP code, based on the finite element method. The left-to-right pulmonary flow ratio and percentage inferior caval blood to the left lung were the highest with the smallest anastomosis and highest inclination: 1.35 and 83.26%, respectively. Dissipated power percentage wa s higher with the largest anastomosis than with the smallest (19.3 vs 15.8% ). It was concluded that, when performing a total cavopulmonary connection, an extracardiac lateral conduit: (i) diverts more flow to the left lung, a nd (ii) shows higher energy losses when compared with a connection with int ra-atrial tunnel. This study could be useful to evaluate the incidence of p ulmonary arteriovenous malformations. (C) 1999 IPEM, Published by Elsevier Science Ltd. All rights reserved.