Introduction of a new optimized total cavopulmonary connection.

BACKGROUND: Several variations of the total cavopulmonary connection (TCPC) have been investigated for favorable fluid mechanics and flow distribution. This study presents a hemodynamically optimized TCPC configuration code-named "OptiFlo." Featuring bifurcated vena cava (superior venacava to inferior vena cava SVC/IVC), it was designed to lower the fluid mechanical power losses in the connection and to ensure proper hepatic blood perfusion to both lungs.
METHODS: A rapid prototype model of the OptiFlo TCPC was built and in vitro control volume flow analysis was performed to evaluate the fluid mechanical power loss performance of the model. Furthermore, computational fluid dynamics simulations were used to investigate the flow patterns in the model, which were compared with those in the planar one-diameter offset TCPC with flared anastomosis sites, the best known TCPC configuration to date.
RESULTS: Compared with the one-diameter offset reference model, the OptiFlo showed lower power losses: -26%, -31%, and -42% for increasing cardiac outputs of 2, 4, and 6 L/minute, respectively. No statistically significant differences were found in power loss between 40:60 and 50:50 SVC/IVC flow ratios (p > 0.1) for the OptiFlo model. The power loss characteristic curve for different left and right pulmonary artery ratios was flatter for the OptiFlo than the one-diameter offset reference model. Pulmonary artery flow was much more streamlined in the OptiFlo compared with the one-diameter offset model.
CONCLUSIONS: The OptiFlo TCPC design exhibits lower power losses with better adaptive distribution of hepatic blood to both lungs and lower blood flow disturbances compared with the planar one-diameter offset TCPC model. Its significantly superior hemodynamic performance at higher cardiac outputs (exercise) rationalizes further design and feasibility studies toward a workable clinical model.