Nonlinear power loss during exercise in single-ventricle patients after the Fontan - Insights from computational fluid dynamics
Nonlinear power loss during exercise in single-ventricle patients after the Fontan - Insights from computational fluid dynamics
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DOI：
10.1161/circulationaha.106.680827
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发表时间：
2007-09-11
期刊：
影响因子：
37.8
通讯作者：
Fogel, Mark A.
中科院分区：
文献类型：
--
作者：
Whitehead, Kevin K.;Pekkan, Kerem;Fogel, Mark A.
背景-我们以前证明，在单心室患者中，通过全腔静脉连接（TCPC）进行Fontan的功率损失（PL）可以通过使用三维MRI解剖重建的计算流体动力学分析来计算。通过TCPC的PL可能在单心室生理学中起作用，并且是心输出量的函数。我们假设，PL通过TCPC增加显着下行使flowconditions.Methods和结果- MRI数据的10例TCPC进行了分析，以获得三维几何形状和流速通过上级腔静脉，下腔静脉，左肺动脉，右肺动脉。稳态计算流体动力学模拟进行了基线条件下使用MRI衍生的流量。通过增加下腔静脉流量，模拟2倍（2x）和3倍（3x）基线流量的运动条件。计算了每种条件下的PL、水头损失和通过TCPC的有效阻力。在左肺动脉/右肺动脉比率为30/70和70/30的条件下重复每种条件，以确定肺血流分流对运动PL的影响。对于每个患者，PL随着心输出量的增加以非线性方式显著增加，即使在标准化以计算压头损失或阻力时也是如此。流量分裂PL在运动中有显着的影响，最有利于右肺动脉flow.Conclusions的几何形状-心输出量和PL之间的关系是非线性的，高度依赖于TCPC的几何形状和肺血流分裂。这项研究证明了在运动条件下研究TCPC的重要性，因为基线条件可能无法充分表征TCPC的效率。
Background - We previously demonstrated that power loss (PL) through the total cavopulmonary connection (TCPC) in single-ventricle patients undergoing Fontan can be calculated by computational fluid dynamic analysis using 3-dimensional MRI anatomic reconstructions. PL through the TCPC may play a role in single-ventricle physiology and is a function of cardiac output. We hypothesized that PL through the TCPC increases significantly under exercise flow conditions.Methods and Results - MRI data of 10 patients with a TCPC were analyzed to obtain 3-dimensional geometry and flow rates through the superior vena cava, inferior vena cava, left pulmonary artery, and right pulmonary artery. Steady computational fluid dynamic simulations were performed at baseline conditions using MRI-derived flows. Simulated exercise conditions of twice (2x) and three times (3x) baseline flow were performed by increasing inferior vena cava flow. PL, head loss, and effective resistance through the TCPC were calculated for each condition. Each condition was repeated at left pulmonary artery/right pulmonary artery ratios of 30/70 and 70/30 to determine the effects of pulmonary flow splits on exercise PL. For each patient, PL increases dramatically in a nonlinear fashion with increasing cardiac output, even when normalized to calculate head loss or resistance. Flow splits had a significant effect on PL at exercise, with most geometries favoring right pulmonary artery flow.Conclusions - The relationship between cardiac output and PL is nonlinear and highly dependent on TCPC geometry and pulmonary flow splits. This study demonstrates the importance of studying the TCPC under exercise conditions, because baseline conditions may not adequately characterize TCPC efficiency.