Simulations Reveal Adverse Hemodynamics in Patients With Multiple Systemic to Pulmonary Shunts
Simulations Reveal Adverse Hemodynamics in Patients With Multiple Systemic to Pulmonary Shunts
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DOI：
10.1115/1.4029429
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发表时间：
2015-03-01
影响因子：
1.7
通讯作者：
Marsden, Alison
中科院分区：
文献类型：
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作者：
Esmaily-Moghadam, Mahdi;Murtuza, Bari;Marsden, Alison
对于诊断为肺动脉闭锁或严重肺动脉狭窄导致肺血流不足的新生儿，可以通过在无名动脉和肺动脉之间放置改良的Blalock-Taussig分流管（MBTS）来缓解发绀。在某些临床情况下，患者接受两个体循环-肺循环连接，要么保持动脉导管未闭（PDA）开放，要么在MBTS的基础上增加额外的中心分流（CS）。这种做法的动机是认为额外的肺血流来源可以有益地增加肺血流，并在血栓形成的情况下提供替代途径的安全性。然而，有临床报告称，当使用一个以上的分流管时，会发生分流管过早闭塞，从而推测多个分流管实际上可能导致不利的血流动力学和死亡率增加。在这项研究中，我们假设多个分流可能会导致不良的流量竞争，导致滞留时间（RT）增加和血栓形成的风险增加，以及肺过度循环。进行了基于计算流体动力学的多尺度模拟，以比较一系列分流配置，并系统地量化血流竞争、肺循环和其他临床相关参数。共23例患者通过系统改变PDA/CS直径、肺血管阻力（PVR）和MBTS位置进行评价，并通过定量氧输送（OD）至全身和冠状动脉床、壁切应力（WSS）、振荡剪切指数（OSI）、WSS梯度（WSSG）和肺动脉（PA）RT以及MBTS进行比较。结果表明，较小的PDA/CS直径可导致血流条件与PA中的血流竞争导致的血栓形成增加一致，较大的PDA/CS直径可导致肺过度融合导致的OD不足。在最差情况下，发现多个分流管可导致RT增加160%，OD减少10%。根据本研究中提供的模拟结果，应严格研究接受多次分流术的患者的临床结局，因为这种做法似乎在OD方面没有获益，实际上可能增加血栓形成风险。
For newborns diagnosed with pulmonary atresia or severe pulmonary stenosis leading to insufficient pulmonary blood flow, cyanosis can be mitigated with placement of a modified Blalock-Taussig shunt (MBTS) between the innominate and pulmonary arteries. In some clinical scenarios, patients receive two systemic-to-pulmonary connections, either by leaving the patent ductus arteriosus (PDA) open or by adding an additional central shunt (CS) in conjunction with the MBTS. This practice has been motivated by the thinking that an additional source of pulmonary blood flow could beneficially increase pulmonary flow and provide the security of an alternate pathway in case of thrombosis. However, there have been clinical reports of premature shunt occlusion when more than one shunt is employed, leading to speculation that multiple shunts may in fact lead to unfavorable hemodynamics and increased mortality. In this study, we hypothesize that multiple shunts may lead to undesirable flow competition, resulting in increased residence time (RT) and elevated risk of thrombosis, as well as pulmonary overcirculation. Computational fluid dynamics-based multiscale simulations were performed to compare a range of shunt configurations and systematically quantify flow competition, pulmonary circulation, and other clinically relevant parameters. In total, 23 cases were evaluated by systematically changing the PDA/CS diameter, pulmonary vascular resistance (PVR), and MBTS position and compared by quantifying oxygen delivery (OD) to the systemic and coronary beds, wall shear stress (WSS), oscillatory shear index (OSI), WSS gradient (WSSG), and RT in the pulmonary artery (PA), and MBTS. Results showed that smaller PDA/CS diameters can lead to flow conditions consistent with increased thrombus formation due to flow competition in the PA, and larger PDA/CS diameters can lead to insufficient OD due to pulmonary hyperfusion. In the worst case scenario, it was found that multiple shunts can lead to a 160% increase in RT and a 10% decrease in OD. Based on the simulation results presented in this study, clinical outcomes for patients receiving multiple shunts should be critically investigated, as this practice appears to provide no benefit in terms of OD and may actually increase thrombotic risk.