Abstract 2211: Large Differences in Efficiency Among Fontan Patients Demonstrated In Patient Specific Models of Blood Flow Simulations

Background: Not all Fontan patients are “equal” despite similar hemodynamics using current diagnostic modalities. Recent advances in imaging and computational fluid dynamics simulations (CFDS) enable the evaluation of both previously unmeasurable parameters (e.g. efficiency (either at rest or with exercise)) and in patient-specific scenarios. We hypothesize CFDS at rest and simulated exercise will demonstrate large differences in pressure and efficiency among Fontan patients. Methods: Using MRI-obtained anatomy and flow, time-dependent, 3-D simulations were performed using a custom finite element solver in 4 patient-specific Fontan models. Flow features, pressure, and energy efficiency were analyzed at rest and with increasing flow to simulate light, moderate and heavy exercise. Resistance boundary conditions enabled simulation at physiologic pressures and vasodilation with “exercise.” Results: Large variations in geometry, efficiency (96 – 87% at rest, 90–75% with exercise) and mean SVC pressure were seen (figure ). Efficiency did not correlate with Fontan pressures and did not decrease linearly with increased exercise. The most efficient among these four particular patients was a traditional t-junction connection though it had one of the highest SVC pressures. Conclusions: Geometries, efficiency and pressure levels vary dramatically among Fontan patients. Patients may have similar hemodynamic performance at rest, but large differences in both efficiency and pressure can be demonstrated during simulated exercise. CFDS and determination of patient specific efficiency may provide an additional tool for risk stratification among patients.