Abstract 13547: Pitfall of Localized Modeling of the Fontan Circulation: Assessment of Total Cavopulmonary Connection in a Global Simulation
Background: Past modeling of the Total Cavopulmonary Connection (TCPC) has focused on manipulating the local geometry, such as caval offset, to minimize energy loss. However, energy loss and hydraulic resistance are mathematical calculations, and their significance to clinically relevant parameters are unknown. Accordingly, we sought to examine the influence of TCPC configuration on the global systemic circulation.
Methods and Results: Two 3-dimensional models of the extracardiac TCPC were constructed to produce high and low hydraulic resistances (model H and L: resistance 0.146 vs. 0.073 mmHg·min/L). They were coupled to an identical hydraulic network that describes the entire circulation based on clinical post-TCPC hemodynamics of a patient with boday surface area of 0.67 m2. This validated multi-scale approach incorporates respiratory effects, and computes global parameters including pulmonary arterial and caval flow/pressure, and cardiac output, and systemic oxygen delivery. Model H exhibited increased velocity and flow stagnation within the TCPC. However, despite energy loss that is >2-fold than model L (1.33 vs. 0.57 mW), model H did not demonstrate worse pulmonary arterial flow or pressures. Difference in aortic and peripheral arterial flow and pressure were <0.5%. There were no significant differences in cardiac output and systemic oxygen delivery between the two models.
Conclusions: Reducing energy loss more than two-folds did not produce major flow dynamic advantages that would translate to superior performance in clinically relevant parameters. These multi-scale simulation results suggest that rather than focusing on energy loss, assessment of TCPC configuration requires examination of impact on the global systemic circulation, and other factors, such as pulmonary vascular resistance and ventricular function, are likely more important to the overall Fontan circulatory performance.
- © 2011 by American Heart Association, Inc.