Aortic displacement and hemodynamics are abnormal in patients with Marfan syndrome: A combined four-dimensional balanced steady-state free precession and four-dimensional flow cardiac magnetic resonance study.

BACKGROUND

Marfan syndrome (MFS) patients with a history of aortic root surgery (ARS) are at increased risk of type B aortic dissection, possibly because the noncompliant graft fails to absorb systolic forces, leading to undampened flow in the proximal descending aorta (pDAo). In this study, we investigated the magnitude and location of abnormal aortic displacement and wall shear stress (WSS) using cardiac magnetic resonance (CMR) imaging.

METHODS

We examined 82 MFS patients (32 with ARS, 34 ± 8 years, 36 women) and 45 age- and sex-matched controls, all undergoing four-dimensional high-resolution balanced steady-state free precession and flow CMR. Peak displacement and WSS were calculated using automated aortic segmentations. Heatmaps were created to identify and quantify regions with abnormal displacement and WSS. The surface areas of abnormal displacement and WSS were quantified in four aortic regions. The Wilcoxon signed-rank test was used for comparison of abnormal CMR parameter quantification, and Pearson correlation was used to assess correlations between displacement and WSS.

RESULTS

WSS was higher in the proximal (p < 0.001) and distal ascending aorta (Aao) (p = 0.031) of ARS MFS patients compared to native MFS patients. ARS MFS patients had significantly larger surface areas of decreased displacement (p < 0.001; present in 97% (31/32) of ARS MFS patients) and increased WSS (p < 0.001; present in 100% (32/32) of patients) in the proximal Aao. There was a trend toward a larger surface area of increased displacement in the pDAo of ARS MFS patients (p = 0.062; present in 72% (23/32) of patients), mainly located in the outer pDAo. pDAo displacement was positively correlated with pDAo WSS (Pearson r = 0.46 [95% confidence interval: 0.13, 0.70], p = 0.008).

CONCLUSION

Aortic displacement and flow characteristics are abnormal in MFS patients, both with and without a history of ARS. ARS MFS patients exhibit distinct features in both the AAo and descending aorta (DAo), particularly in the proximal DAo, which is the region susceptible to type B aortic dissections.