| Description |
- Background: Pulmonary artery stenosis, neoaortic dilatation, and neoaortic valve insufficiency are among the most frequent complications of the arterial switch operation (ASO) for repair of dextro-transposition of the great arteries (d-TGA). It remains difficult to predict which patients will ultimately need aortic or pulmonary arterial reintervention.
Purpose: To characterize hemodynamics within the pulmonary arteries and aorta using four-dimensional (4D) flow cardiac MRI in patients with d-TGA after the ASO.
Materials and methods: 44 patients with d-TGA after the ASO (d-TGA-ASO) and 25 patients with normal native cardiac anatomy (control) underwent 1.5T cardiac MRI with 4D flow imaging. Analysis of each 4D flow dataset included three-dimensional segmentations of the aorta and pulmonary arteries, which were used for quantification of velocity, stasis, kinetic energy (KE), energy loss, and wall shear stress (WSS). Pulse wave velocity (PWV) was also quantified within the aorta. Statistical analysis included tests for paired comparisons between controls and 25 age-matched d-TGA-ASO patients and unpaired whole-group comparisons.
Results: The age-matched d-TGA-ASO subgroup (mean age 15.7 years ± 2.4 [SD]) demonstrated higher maximum velocity (P < 0.0001), mean velocity (P < 0.0001), maximum KE (P < 0.0001), mean KE (P < 0.0001), energy loss (P < 0.0001), maximum WSS (P < 0.0001), and mean WSS (P < 0.0001) within the pulmonary arteries compared with controls (mean age 15.5 years ± 2.4 [SD]). Aortic maximum (P = 0.0004) and mean (P = 0.04) velocity, maximum (P = 0.004) and mean (P = 0.0046) KE, energy loss (P = 0.0009), maximum WSS in five of six regions [range P = 0.0007 to P = 0.0210], and mean wall shear stress in three of six regions (range P= 0.0042 to P = 0.0042) were higher in age-matched d-TGA-ASO patients compared with controls.
Conclusion: D-TGA-ASO patients demonstrate flow abnormalities within the pulmonary arteries and aorta, which may provide insight into the consequences of the ASO and the need for cardiovascular reintervention.
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