Abstract 3412: Viscous Dissipation Power Loss of the Total Cavopulmonary Connection Evaluated Using Phase Contrast Magnetic Resonance Imaging
Introduction: Two variations of the total cavopulmonary connection (TCPC) used to correct single ventricle physiology are the intra-atrial (IA) and the extra-cardiac (EC) connections. There is no consensus on a surgically favored procedure and little information is available on in vivo flow dynamics to support an individual choice.
Methods: A stack of 3D phase contrast magnetic resonance imaging (PC MRI) was acquired in the coronal direction for 8 patients with an average age of 8 years and M/F ratio of 5/3. Slice thickness was 6 mm, 25 cardiac phases per cycle, and an average of 7 slices were obtained spanning the TCPC. Viscous dissipation power loss (PL) was evaluated using the central slice of the TCPC.
Results: PLs as a function of the cardiac cycle are shown in figure 1a⇓. Vorticity contour maps with streamlines for an EC and IA TCPC are shown in figure 1b⇓. Table 1⇓ summarizes the results. Significantly higher PLs (p <0.02) and PL range (p<0.01) were observed in the EC TCPC. Losses for ECs occurred near the walls, while IA losses were related to vortices generated in the center of the TCPC. There were no significant differences between the cardiac outputs of the two groups.
Conclusions: This is the first time PLs have been evaluated in the TCPC in vivo using PC MRI. Lack of compliance and contractility within the EC could partly contribute towards these differences in the PLs compared to the more dynamic IA TCPCs.