Abstract 1940: Non-Linear Power Loss During Exercise in Single Ventricle Patients After the Fontan - Insights from Computational Fluid Dynamics
We have previously demonstrated that power loss (PL) through the total cavopulmonary connection (TCPC) in single ventricle pts undergoing Fontan can be calculated by computational fluid dynamic (CFD) analysis using 3-D MRI anatomic reconstructions. PL through the TCPC may play a role in single ventricle physiology and varies with TCPC geometry. In addition, PL is a function of cardiac output (CO) and may increase in a non-linear fashion.
Hypothesis: PL through the TCPC is a function of CO and the relationship between CO and PL may be important in characterizing the function of the TCPC.
Methods: MRI data of 8 pts with a TCPC were analyzed to obtain 3D geometry as well as flow rates through the SVC, IVC, LPA and RPA. Steady flow CFD simulations were performed at baseline conditions using the CFD mesh and MRI-derived flow conditions. Simulated exercise conditions of twice (2x) and three times (3x) baseline MRI flow were performed by increasing IVC flow. PL through the TCPC was calculated for each condition.
Results: For each model, PL increases in a dramatically non-linear fashion with increasing cardiac output (see graph). On average, there was a 9 fold (6–12) increase from baseline to the 2x and 33 fold (29 – 45) to the 3x conditions. Baseline power loss did not always predict the exercise power loss.
Conclusions: The relationship between CO and PL is non-linear, with as much as a 45 fold increase in power loss from baseline to simulated maximal exercise. Additionally, the relationship is very dependent on TCPC geometry. This study demonstrates the potential importance of studying the TCPC under exercise conditions, as studying baseline conditions may not adequately characterize the TCPC.