Numerical simulation and hemodynamic analysis of the modified Blalock-Taussig shunt.

The modified Blalock-Taussig (mB-T) shunt is an effective palliative surgical method in the treatment of cyanotic congenital heart diseases. It increases the pulmonary blood flow through an implanted shunt between systemic and pulmonary arteries. The surgical technique improved over the years. However, it is still a challenge to control appropriate distribution of blood flow through this shunt after this kind of procedure till now. Here, we report on the method of computational fluid dynamics (CFD) for the hemodynamic studies of a patient-specific case after the mB-T shunt. The analysis system that we validated previously in the studies of the Norwood procedure was applied to predict the hemodynamic characteristics in the mB-T hunt area. The real-time velocities derived from Echocardiography measurements and the blood pressure wave reflections from peripheral vessels were utilized as boundary conditions to physiologically capture the blood flow information in the simulation. The local pressure, blood flow distribution and wall shear stress were calculated. The results suggest pressure decreases greatly through the shunt and around 40% of blood flow is distributed from the systemic circulation to pulmonary arteries in one cardiac cycle. These indict computational hemodynamics may be applied in future studies of establishing quantitative standards to evaluate the outcomes of the mB-T shunt and to optimize the implantation of the mB-T shunt in virtual surgeries.