Abstract 15056: Complex Blood Flow Disturbance and Reduced Mean Wall Shear Stress contribute to the Aortic Disease of Marfan Syndrome: Insights from Time-Resolved, 3D Phase-Contrast Magnetic Resonance Imaging
Background: Marfan syndrome (MFS) predisposes to progressive aortic dilation and dissection. Complex flow disturbance and low wall shear stress (WSS) are increasingly recognised as potentially important in the initiation and progression of aortic dilation in diseases such as bicuspid aortic valve aortopathy and abdominal aortic aneurysm, but their role in MFS is not known.
Methods: 20 MFS patients (10 female, age 35+/−8years) and 20 healthy volunteer controls (9 female, age 36+/-7yrs) underwent time-resolved, 3D phase-contrast magnetic resonance imaging at 3T. Aortic blood flow was visualised using particle traces and streamlines. WSS was determined by interpolation of the near wall velocity gradient at 12 points around the aortic lumen, manually segmented at each of 6 anatomical locations in the aorta, at 16-22 timepoints throughout the cardiac cycle.
Results: There was major vortical flow disturbance (defined as one or more aortic segments with >25% aortic lumen occupied by vortical flow) in all patients with MFS compared to 7/20 controls (p<0.001) (Figure 1). Flow disturbance was most common in aortic regions commonly affected by aortic dissection (Figure 2, upper pane). Global WSS was lower in MFS patients than controls: 0.32 ± 0.027 v 0.39 ± 0.048 (p<0.0005), with all evaluated regions affected (Figure 2, lower pane).
Conclusion: MFS is characterised by a generalised decrease in WSS, and regional vortical flow disturbance, most marked in the regions of the aorta most commonly affected by aortic dissection. These changes may contribute to the aortic dilation and dissection seen in MFS and may be novel biomarkers of risk of dissection when tested in prospective studies.
- © 2011 by American Heart Association, Inc.