Hemodynamic Geometrical Multiscale Numerical Study On Modified Blalock-taussig Surgery With Different Anastomosis

The single ventricular heart syndrome (SVHS) was a fatal congenital heartdiseases. Its clinical manifestations included hypoplasia, atresia of the right ventricle,pulmonary stenosis and atrial artery septal defect. These defects led patient infantswith inadequate pulmonary blood flow, severely low blood oxygen saturation andusually accompanied by cyanosis surface phenomenon.The surgery of Systemic-to-Pulmonary Shunt intends to divert more blood flowto the pulmonary circulation by adding an artery shunt between the systemiccirculation and pulmonary circulation. Modified Blalock-Taussig shunt(MBTS) was apalliative surgery, one of the common Systemic-to-Pulmonary Shunts, which wasinterposed a systemic-to-pulmonary artery shunt between innominate artery(IA) andpulmonary artery(PA).Presently, medical doctors always performed this surgery basedon their sense and experience, which was lack of proper pre-operation designed andincreased the surgery risk.The study was based on hemodynamic theory and clinical datum to build0D/3Dcoupled multiscale model of MBTS. Geometric multiscale method was used toperform the numerical simulation by coupling the three-dimensional (3D) arterymodel with a zero-dimensional (0D) lumped parameters model of the cardiovascularsystem, the interaction of two iterative calculations were performed to completehemodynamic geometric multiscale simulation.Firstly, our study established complexity0D models of patient with SVHS andcompared the simulation results with clinical practice. Then, based on the complex0Dpatient’s model, post-operative0D model of MBTS was set up and its hemodynamicbehaviors were discussed.Secondly, the system and pulmonary artery with the clinical CT images of infantswas reconstructed and bypass graft anastomosis was operated in different ways bybuilding three kinds of3D surgery models including side-to-side (STS), end-to-side(ETS) and bilateral side to side (BSTS).Thirdly,0D/3D coupled multiscale model was established based on the0DMBTS model. The article discussed datum interchange of different dimensions, andachieved numerical simulation of0D/3D coupling algorithm. Three different models were hemodynamic geometry multiscale simulated, and we discussed the differentwith hemodynamic parameters.The results showed that: STS and ETS anastomosis both could significantlyincrease pulmonary flow. The Rrpa/lpaof ETS, STS and BSTS were196.17%,72.27%,91.18%. STS anastomosis model owned the balance of the pulmonary artery bloodperfusion. BSTS anastomosis existed obvious swirling flow phenomena. It made thewall shear stress of bypass increases5Pa. The OSI value of STS model was thesmallest. It was about0.031. Thus MBTS surgery with STS astomosis proceduremight reduce the risk of atherosclerosis.Hemodynamic geometric multiscale coupling method for MBTS simulation, notonly used to obtain the infants’ hemodynamic characteristics of blood circulationsystem by simulation, but also partial bypass vascular hemodynamic flow informationwas available. The computed result tends to be more real physiologically, which wassatisfied with personalized surgical planning needs.