Transposition of the great arteries (TGA) is a congenital heart disease characterized by abnormal spatial arrangement of the two main vessels, with the aorta arising from the pulmonary valve and the main pulmonary artery arising from the aortic valve. TGA surgical repair with the arterial switch operation (ASO) involves physically repositioning the aorta and the pulmonary artery in their correct anatomical location, as well as separately moving the coronary arteries. Following ASO, decreased aortic distensibility and enlarged aortic root have been observed, together with late complications such as coronary artery obstruction, neoaortic valvar insufficiency, and arrhythmia . Clearly, further knowledge of the hemodynamics in the neoaorta following ASO can be helpful in understanding the physiology of repaired-TGA. We suggest that engineering tools can provide access to such knowledge, both experimentally and computationally. 4D flow data from magnetic resonance (MR) imaging can generate excellent maps of velocity streamlines and — to our knowledge — has never been applied to this clinical problem. In addition, 4D MR flow data gathered in-vitro (hence more reproducible and more stable than in-vivo) can be a resourceful tool for validating a computational fluid dynamics (CFD) model of the same problem. The experimental model, lacking respiration effects and concerns about scanning time, can also be used for exploring the optimal spatial and temporal resolution for improving the quality of the data. Ultimately, we suggest that a synergistic approach (experimental 4D MR flow + CFD study) carried out at a patient-specific level can provide knowledge about the hemodynamics in the neoaorta following ASO. For this purpose, we present two comparisons:
(a) TGA anatomy vs. an age-matched healthy subject
(b) in-vitro vs. in-silico.