Abstract 18996: Swirls and Twirls: Flow Patterns in the Reconstructed Aorta in Single Ventricles - A Cardiac Magnetic Resonance Four-Dimensional Flow Study

Abstract

Background: Flow patterns in the aorta are the result of the interplay of ventricular function and aortic geometry and have been implicated in the development of atherosclerotic disease, aortic dilation and aneurysm formation. It may also lend a clue to inefficient power output of the heart. Previous work from our laboratory has demonstrated decreased power output in pts with single right ventricles (SRV) as compared with single left ventricle pts; this may be partially due to the necessity of aortic reconstruction (recon) in SRV pts. The purpose of this study is to determine the flow patterns in recon. Methods: A retrospective review of all SRV pts who underwent cardiac magnetic resonance 4-dimensional phase contrast flow imaging from January 2012 to the present. The phase contrast slab was obtained in the candycane view of the aorta. Post processing was performed using GT Flow. Results: A total of 11 SRV pts who underwent recon were found, ages 5.1± 1.8 yrs with cardiac index of 4.8± 1.8 liters/minute/meter 2 ; 5 with Fontan and 6 with bidirectional Glenn/HemiFontan. A right handed helix (clockwise when viewed in the direction of flow) was visualized in all pts in the ascending aorta (AAo); in one who had a markedly dilated transverse arch, a secondary helical pattern was created in that region. In pts with a narrowed isthmus (46± 4.3% of AAo diameter), helical flow changed to a left handed helix in the descending aorta (DAo); in those without narrowing (65± 11% of AAo diameter), little helical flow was noted in the DAo (P=0.05). Conclusion: SRV undergoing recon demonstrated a right handed helix in the AAo; those with a narrowed isthmus demonstrated a reversal of the helix to a left handed pattern in the DAo while those without narrowing showed little secondary flow. Significant isthmus narrowing alters secondary flow patterns in the DAo. These observations may yield a clue to decreased SRV power output.