Abnormal aortic flow related to left ventricular mass and volume in coarctation: a four-dimensional flow CMR study

Background After successful repair for coarctation of the aorta (CoA) abnormal blood flow patterns can be present, which may have a negative impact on left ventricular (LV) performance. The aim of this study is to investigate the relationship between aortic haemodynamics assessed by four-dimensional flow (4D flow) cardiac magnetic resonance imaging (CMR) and LV performance in CoA patients. Methods CoA patients with a clinical indication for CMR underwent additional 4D flow acquisition. Wall shear stress, oscillatory shear index, vorticity, viscous dissipation, energy loss, kinetic energy and velocity angle were assessed for several aortic segments at peak-systole. Global pulse wave velocity (PWV) was assessed for the entire aorta. Results In total, 17 CoA patients were included. Increased velocity angle in the ascending aorta was correlated with decreased LV mass (p=0.0445). Energy loss at the CoA site and increased degree of vorticity in the descending aorta were correlated with increased LV end-diastolic and end-systolic volume (p=0.0499, p=0.0461, respectively). Aortic PWV was correlated with LV mass and LV end-systolic volume (p=0.0385, p=0.0397, respectively). Conclusion Adverse aortic-ventricular interaction in CoA patients was demonstrated by abnormal aortic haemodynamics by 4D flow assessment which were associated impaired LV performance. 4D flow CMR may provide novel parameters to assess aortic-ventricular interaction.