Numerical Simulation of the Influence of Geometric Configurations on Pressure Difference in the Intraventricular Tunnel

OBJECTIVE: The geometric configuration of the intraventricular tunnel is related to the re-intervention of left ventricular outflow tract stenosis after double outlet right ventricle (DORV) correction. Hemodynamic simulation was performed in order to study the influence of the geometric configuration of the IVT on the pressure difference. METHODS: CT images of DORV were processed to reconstruct 3D models of left and right ventricular flow chambers and aortic valve orifice, and then the size and relative position of the aortic valve orifice and ventricular septal defect were determined. Twenty five groups of the idealized models were established according to orthogonal test design and computational fluid dynamics method was applied to simulate hemodynamics. Three factors of geometric configuration were considered for the study of their influences on the pressure difference. The first factor is the distance between the ventricular septal defect and the plane of the aortic valve (D(SA)), the second factor is the ejection angle of blood from left ventricle flowing into the IVT (A(LT)), and the third factor is the turning radius of the IVT (R(TT)). SPSS software was employed to perform the orthogonal analysis. Additionally, twelve models with different turning radii were established for hemodynamic analysis, with the turning radii increasing from 0 mm with an interval of 1 mm, so as to study the influence of turning radius on pressure difference of IVT. RESULTS: The analysis of variance showed that only the change of R(TT) had a significant effect on the pressure difference (P = 0 < 0.05), while the change of D(SA) and A(LT) had no significant effect on the pressure difference (P = 0.459 > 0.05, P = 0.263 > 0.05). The pressure difference decreases with the increase of R(TT). When R(TT) reaches 6 mm, the pressure difference gradually remains unchanged with the increase of R(TT), and the rate of change is less than 5%. CONCLUSION: R(TT) in the IVT is the main factor affecting the pressure difference. A small R(TT) will lead to a large pressure difference in the IVT. When R(TT) increases to 6 mm, the pressure difference in the IVT remains nearly unchanged. When performing the right ventricular double outlet correction; the turning radius of the IVT should be about 6 mm to ensure relatively small pressure difference.