Arbia Gregory, Corsini Chiara, Baker Catriona, Pennati Giancarlo, Hsia Tain-Yen, Vignon-Clementel Irene E
INRIA Paris-Rocquencourt, Le Chesnay Cedex, France and UPMC Univ Paris 6, Laboratoire Jacques-Louis Lions, Paris, France.
Laboratory of Biological Structure Mechanics, Department of Chemistry, Materials and Chemical Engineering 'Giulio Natta', Politecnico di Milano, Milan, Italy.
Cardiovasc Eng Technol. 2015 Sep;6(3):268-80. doi: 10.1007/s13239-015-0212-3. Epub 2015 Jan 22.
Single ventricle heart defects involve pathologies in which the heart has only one functional pumping chamber. In these conditions, treatment consists of three staged procedures. At stage 1 pulmonary flow is provided through an artificial shunt from the systemic circulation. Representative hemodynamics models able to explore different virtual surgical options can be built based on pre-operative imaging and patient data. In this context, the specification of boundary conditions is necessary to compute pressure and flow in the entire domain. However, these boundary conditions are rarely the measured variables. Moreover, to take into account the rest of the circulation outside of the three-dimensional modeled domain, a number of reduced order models exist. A simplified method is presented to iteratively, but automatically, tune reduced model parameters from hemodynamic data clinically measured before stage 2 surgery. Patient-specific local hemodynamics around the distal systemic-to-pulmonary shunt anastomosis and the connected pulmonary arteries are also analyzed. Multi-scale models of pre-stage 2 single ventricle patients are developed, including a 3D model of shunt-pulmonary connection and a number of pulmonary arteries. For each pulmonary outlet a total downstream resistance is identified, consistent with measured flow split and pressures. Target pressures such as minimum, maximum or average over one or both lungs are considered, depending on the clinical measurement. When possible, both steady and pulsatile identifications are performed. The methodology is demonstrated with six patient-specific models: the clinical target data are well-matched, except for one case where clinical data were subsequently found inconsistent. Inhomogeneous pressure, swirling blood flow patterns and very high wall shear stress 3D maps highlight similarities and differences among patients. Steady and pulsatile tuning results are similar. This work demonstrates (1) how to use routine clinical data to define boundary conditions for patient-specific 3D models in pre-stage 2 single ventricle circulations and (2) how simulations can help to check the coherence of clinical data, or provide insights to clinicians that are otherwise difficult to measure, such as in the presence of kinks. Finally, the choice of steady vs. pulsatile tuning, limitations and possible extensions of this work are discussed.
单心室心脏缺陷涉及心脏只有一个功能性泵腔的病理状况。在这些情况下，治疗包括三个阶段的手术。在第一阶段，通过从体循环建立人工分流来提供肺血流。基于术前成像和患者数据，可以构建能够探索不同虚拟手术方案的代表性血流动力学模型。在这种情况下，指定边界条件对于计算整个区域的压力和流量是必要的。然而，这些边界条件很少是测量变量。此外，为了考虑三维建模域之外的其余循环，存在一些降阶模型。本文提出了一种简化方法，可根据第二阶段手术前临床测量的血流动力学数据迭代且自动地调整降阶模型参数。还分析了患者特异性的远端体肺分流吻合口及相连肺动脉周围的局部血流动力学。建立了第二阶段手术前单心室患者的多尺度模型，包括分流与肺连接的三维模型和若干肺动脉模型。对于每个肺出口，确定了与测量的血流分流和压力一致的总下游阻力。根据临床测量情况，考虑一个或两个肺上的最小、最大或平均等目标压力。在可能的情况下，进行稳态和脉动识别。用六个患者特异性模型展示了该方法：除了一个病例后来发现临床数据不一致外，临床目标数据匹配良好。不均匀压力、旋转血流模式和非常高的壁面剪切应力三维图突出了患者之间的异同。稳态和脉动调整结果相似。这项工作证明了（1）如何使用常规临床数据为第二阶段手术前单心室循环中的患者特异性三维模型定义边界条件，以及（2）模拟如何有助于检查临床数据的一致性，或为临床医生提供难以测量的见解，例如在存在扭结的情况下。最后，讨论了稳态与脉动调整的选择、这项工作的局限性和可能的扩展。
