Effects of exercise and respiration on hemodynamic efficiency in CFD simulations of the total cavopulmonary connection
Effects of exercise and respiration on hemodynamic efficiency in CFD simulations of the total cavopulmonary connection
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DOI：
10.1007/s10439-006-9224-3
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发表时间：
2007-02-01
影响因子：
3.8
通讯作者：
Taylor, Charles A.
中科院分区：
文献类型：
--
作者：
Marsden, Alison L.;Vignon-Clementel, Irene E.;Taylor, Charles A.
先天性心脏缺陷与一个单一的功能心室，如发育不良的左心综合征和三尖瓣闭锁，需要分期手术的方法来分离体循环和肺循环。最后，心脏的静脉或肺侧通过用改良的t形连接直接连接腔静脉和肺动脉来旁路。Fontan手术（全腔静脉连接，TCPC）完成了这一分离过程。迄今为止，在这种低压、被动流、胸内系统中的计算流体动力学（CFD）模拟忽略了呼吸对生理的假定重要影响，并且从未考虑过运动等更高的“压力”状态。我们假设，将呼吸和运动的影响，将提供更现实的估计TCPC的性能。通过定制有限元求解器对两个患者特定Fontan模型进行时间依赖性3D血流模拟，该模型具有新型呼吸模型，用于生成生理时变血流条件。血流特征，压力和能量效率进行了分析，在休息和增加流速，以模拟运动条件。模拟产生了与导管插入术和超声心动图测量的数据相当的真实压力和流量数据，并证明了由于流量中小尺度涡流强度的增加，运动和呼吸的能量耗散（即性能降低）大幅增加。正如预期的那样，这些变化高度依赖于患者特定的解剖结构和Fontan几何结构。我们建议，呼吸和运动应纳入TCPC CFD模拟提供越来越现实的评估TCPC的性能。
Congenital heart defects with a single functional ventricle, such as hypoplastic left heart syndrome and tricuspid atresia, require a staged surgical approach to separate the systemic and pulmonary circulations. Ultimately, the venous or pulmonary side of the heart is bypassed by directly connecting the vena cava to the pulmonary arteries with a modified t-shaped junction. The Fontan procedure (total cavopulmonary connection, TCPC) completes this process of separation. To date, computational fluid dynamics (CFD) simulations in this low pressure, passive flow, intrathoracic system have neglected the presumed important effects of respiration on physiology and higher "stress" states such as with exercise have never been considered. We hypothesize that incorporating effects of respiration and exercise would provide more realistic estimates of TCPC performance. Time-dependent, 3D blood flow simulations are performed by a custom finite element solver for two patient-specific Fontan models with a novel respiration model, developed to generate physiologic time-varying flow conditions. Blood flow features, pressure, and energy efficiency are analyzed at rest and with increasing flow rates to simulate exercise conditions. The simulations produce realistic pressure and flow data, comparable to that measured by catheterization and echocardiography, and demonstrate substantial increases in energy dissipation (i.e. decreased performance) with exercise and respiration due to increasing intensity of small scale vortices in the flow. As would be expected, these changes are highly dependent on patient-specific anatomy and Fontan geometry. We propose that respiration and exercise should be incorporated into TCPC CFD simulations to provide increasingly realistic evaluations of TCPC performance.