Aortic Disturbed Flow Is Associated with Aortic Angle in Patients with Tetralogy of Fallot or Double-Outlet Right Ventricle.

Purpose: Aortopathy, characterized by aortic dilatation caused by cystic medial necrosis, typically develops in adulthood but has been observed at a young age in patients with tetralogy of Fallot. We hypothesized that some patients with tetralogy of Fallot or double-outlet right ventricle experience early-onset aortic disturbed flow. This study aimed to identify and analyze the causes of disturbed flow using 4D flow MRI.

Methods: This study included 24 patients who underwent 4D flow MRI at our institution between January 2022 and September 2024. MRI and cardiac catheterization were performed during follow-up. 4D flow MRI was used to detect disturbed flow and investigate its underlying causes.

Results: The mean age of patients with tetralogy of Fallot or double-outlet right ventricle was 12 years (range, 1 to 37 years). Of the 24 participants, 11 (46%) exhibited disturbed flow. Patients with disturbed flow had significantly higher Valsalva Z-scores (4.7 ± 3.1 vs. 2.4 ± 1.4, P = 0.013) and a significantly narrower left ventricular outflow tract-ascending aorta angle (113.5 ± 11.6 vs. 127.1 ±  6.7°, P = 0.002). Wall shear stress and energy loss were not significantly different between the 2 groups.

Conclusion: Aortic disturbed flow may occur in patients with tetralogy of Fallot or double-outlet right ventricle, regardless of age, suggesting an association with the left ventricular outflow tract-ascending aorta angle. The occurrence of disturbed flow at a young age should be noted as it may contribute to the future progression of aortopathy.