| Summary: | Purpose: Different altered flow dynamics may influence ascending aorta (AAo) dilation morphotypes in bicuspid aortic valve (BAV) (1). Using 4D-flow CMR, we aimed to identify flow variables related to root or ascending dilation in BAV.
Methods: One-hundred and one BAV patients (no severe valvular disease, aortic diameters <45 mm) underwent 4D-flow on GE 1.5 T Signa scanner (GE Healthcare, Waukesha, USA). Peak velocity, jet angle, normalized flow displacement, in-plane rotational flow (IRF), systolic flow reversal ratio (SFRR) and wall shear stress (WSS) were evaluated at proximal, mid and distal AAo. Dilation morphotypes were classified as non-dilated, ascending and root (2), using z-score > 2. Univariate and multivariate linear regression were used to identify factors related to dilation. ROC curves were performed to assess the relationship between variables obtained in the multivariate analysis and dilation morphotypes.
Results: Fusion phenotype was right-left (RL) in 78 patients, and right-non coronary (RN) in 23. Dilation morphotype was non-dilated in 24 patients, root in 11 and ascending in 66. On univariate analysis, BAV phenotype (RN), displacement and circumferential WSS presented the highest odds ratios (Table). On multivariate analysis, sex (male), proximal velocity and axial WSS were related to root morphotype (AUC 0.91, P < 0.001), while RN-BAV, distal IRF, and mid-AAo SFRR and circumferential WSS were related to ascending morphotype (AUC 0.81, P < 0.001) (Table and Figure).
Univariate analysis of aortic dilation
Multivariate analysis of aortic dilation
Root morphotype
Ascending morphotype
Odds Ratio
P-value
Odds Ratio
P-value
Odds Ratio
P-value
BAV phenotype (RL/RN)
3.23
0.02
1.33
0.008
Sex (Male)
1.10
0.02
4.67
0.005
Prox
Peak velocity
1.02
0.028
1.10
0.043
Jet angle
1.05
0.037
Displacement
3.56
0.001
1.11
0.021
IRF
1.01
0.002
WSSaxial
1.20
0.003
7.64
0.008
WSSCireumf
1.65
0.05
Mid
Jet angle
1.07
0.006
Displacement
2.46
0.002
IRF
1.01
0.007
SFRR (%)
1.20
0.001
1.2
<0.001
WSSaxial
1.21
0.05
WSSCireumf
2.43
0.02
2.23
0.037
Dist
IRF
1.01
0.026
1.10
0.026
WSSCireumf
1.49
0.05
SFRR (%)
1.10
0.005
Table.Univariate and multivariate factors related to of aortic dilation and dilation morphotypes.
Figure.ROC curves showing flow variables related to aortic dilation morphotypes.
Conclusions: Different altered flow parameters are related to root and ascending morphotypes in BAV. Further longitudinal studies are warranted to evaluate the impact of these flow parameters in determining the risk for aortopathy.
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