Ascending thoracic aorta aneurysm repair induces positive hemodynamic outcomes in a patient with unchanged bicuspid aortic valve

We report a patient-specific case of bicuspid aortic valve with fusion of right and left coronary leaflets (R-L type I BAV), moderate aortic valve deficiency and ascending thoracic aortic aneurysms (ATAA) who was treated by only ascending aorta replacement preserving the BAV. The flow eccentricity, the helicity intensity (h₂), the circumferential time averaged wall shear stress (TAWSS_{circumferential}), the cumulative viscous energy loss at the systolic peak (E_L^') and the pulse wave velocity (PWV) were calculated by combining 4D flow MRI and CFD analysis before (Stage I) and after (Stage II) the surgical procedure. CFD analyses assumed rigid walls, a non-Newtonian behavior for the blood and MRI measured patient-specific blood flow profiles as inlet boundary conditions. Stage II results showed suppression of recirculation in the ascending aorta, loss of jet flow impingement onto the aortic wall, maximum TAWSS_{circumferential} decrease (from 6.69 Pa in Stage I to 6 Pa in Stage II), reduction of flow helicity (from 10.97 in Stage I to 8.47 in Stage II) and E_L^' (from 15.8 mW in Stage I to 11.2 mW in Stage II). However, Flow_eccentricity and PWV were found higher in Stage II due to the diameter reduction (Flow_eccentricity = 0.60 in Stage I and Flow_eccentricity = 0.91 in Stage II; PWV = 3.80 m/s in Stage I and PWV = 9.37 m/s in Stage II). Our work has permitted to compute for the first time the hemodynamic alterations obtained after restoration of normal ascending aorta and sinotubular junction geometry even preserving an R-L type I BAV with still acceptable function.