反脈動心室輔助器嵌入降主動脈中，由於側接流道設計與反脈動血泵作動將改變自然主動脈血管中的流場特徵。本文目的在於探討嵌入的T型歧管與血管動脈腔室之間彈性不相符(Compliance Mismatching)對於血栓形成與血管於嵌入區域生物適應性之影響效應，並分析其流場對於血球細胞破壞與壁面剪應力的影響。本研究使用流體力學商用軟體FLUENT之使用者定義方程式(User-Defined Function)來進行流固耦合(Fluid-Structure Interaction)計算流體力學(Computational Fluid Dynamics)模擬，配合動物實驗所獲得的流場邊界條件來求解出血管脈動耦合效應，並以壁面剪應力(Wall Shear Stress)、剪應力梯度(Wall Shear Stress Gradient)、剪應力震盪指數(Oscillatory Shear Index)及溶血指數(Hemolysis Index)等來診斷血管壁病變發生及產生血栓或溶血的可能性。嵌入歧管與血管間之接合處間隙模型對於分析彈性不相符現象與其生物相容性問題是相當重要的。從模擬結果得知，1) T型歧管流場中產生之迴流區並未持續性停滯；2)彈性不相符之區域有較大之剪應力梯度變化; 3)歧管壁面有伴隨高剪應力的的沖刷，使血小板不會沉積附著形成血栓; 4)彈性不相符之區域，其間隙內之血液並未成滯留狀態，於週期之中皆有規律性的沖刷流動，可避免血栓的形成; 及5)以計算流體力學模擬分析嵌入體與動脈間流固耦合之流場現象與應力狀態，其接合處間隙變化模型是重要且關鍵的。

The native blood flow characteristics in aorta will change when a para-aortic blood pump (PABP) is implanted and operated in a counter-pulsatile manner. The objective of this research is to study the effect of compliance mismatching between the aortic lumen and the inserted T-manifold on the thrombogenesis and vessel adaptation over the implant site. To analyze the disturbed flow field effects on blood cell damage and the device-induced wall stresses, a fluid-structure interaction (FSI) computational fluid dynamics (CFD) simulation was performed using a commercially available FLUENT code and a user-defined dynamic grid system. The boundary conditions required for the present CFD simulations are supplied by the inflow/outflow rates measured in animal experiment. Wall shear stress, wall shear stresses gradient, pressure, oscillatory shear index (OSI), and hemolysis index (HI) were examined to diagnose the possibility of thrombogenicity and vessel maladaptation. The modeling of the graft/vessel juncture was found crucial for analyzing the compliance mismatching effect and the biocompatibility of the implant. The present CFD analysis reveals that 1)there exists nowhere in the pulsatile juncture flow that is constantly stagnant; 2)wall shear stress gradient is found high around the compliance mismatching corners; 3)high-shear and turbulent wash-out effect in the T-manifold helps reduce platelet deposition on artificial surfaces; and 4)the flow in the compliance mismatching corner is non-stationary, forming an automatic wash-out mechanism to avoid local thrombus formation. In summary, the CFD simulation thoroughly analyzed the flowfield and stress conditions associated with the T-manifold implant and the graft/vessel juncture gap modeling is crucial for a valid fluid/structure interaction of the present design

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