BACKGROUND: The Total Cavopulmonary Connection (TCPC), used for repairof patients with single ventricle physiology, creates a passive system of blood flow into the pulmonarycirculation where enhanced energy efficiency may lead to improved long term patient outcomes. Previousnumerical and in vitro studies using steady flow have shown that incorporation of SVC (superior venacava) and IVC (inferior vena cava) offsets lead to decreased energy losses. We hypothesize that the optimalTCPC offset design found in these previous steady flow experiments may not be the optimal design in pulsatileflow situations. MATERIAL/METHODS: 3-D finite volume numerical models were used to simulate flow throughthe total cavopulmonary connection. We ran steady and pulsatile flow experiments through 4 TCPC designseach with different SVC to IVC offsets (0.1/4, 1/2, 1 diameter offsets). The total energy (power) lossfor each TCPC model was calculated. RESULTS: In steady flow experiments, % difference in energy lossbetween the most optimal and least optimal design was 26%. In contrast, in pulsatile flow experimentsthe % difference was only 8%. CONCLUSIONS: Our results demonstrate the improvements in energy loss seenusing SVC-IVC offsets in steady flow experiments do not necessarily translate to pulsatile flow situations.Overall there was lower differences in efficiency between all TCPC designs in the pulsatile flow experiments.These results emphasize the need for further studies to fully define the relationship between energylosses and TCPC vessel architecture in non-steady flow physiologic situations.

Keywords: Blood Flow Velocity, Cardiovascular System, Fontan Procedure, Hemodynamic Processes, Models, Theoretical, Regional Blood Flow, Research Support, Non-U.S. Gov, Time Factors