Domogo Andrei A, Ottesen Johnny T
University of the Philippines Baguio, Baguio City, Philippines; Roskilde University, Roskilde, Denmark.
Roskilde University, Roskilde, Denmark.
J Theor Biol. 2021 Oct 7;526:110791. doi: 10.1016/j.jtbi.2021.110791. Epub 2021 Jun 1.
This study develops a hemodynamic model involving the atrium, ventricle, veins, and arteries that can be calibrated to experimental results. It is a Windkessel model that incorporates an unsteady Bernoulli effect in the blood flow to the atrium. The model is represented by ordinary differential equations in terms of blood volumes in the compartments as state variables and it demonstrates the use of conductance instead of resistance to capture the effect of a non-leaking heart valve. The experimental results are blood volume data from 20 young (half of which are women) and 20 elderly (half of which are women) subjects during rest, inotropic stress (dobutamine), and chronotropic stress (glycopyrrolate). The model is calibrated to conform with data and physiological findings in 4 different levels. First, an optimization routine is devised to find model parameter values that give good fit between the model volume curves and blood volume data in the atrium and ventricle. Patient-specific information are used to get initial parameter values as a starting point of the optimization. Also, model pressure curves must show realistic behavior. Second, parametric bootstrapping is performed to establish the reliability of the optimal parameters. Third, statistical tests comparing mean optimal parameter values from young vs elderly subjects and women vs men are examined to support and present age and sex related differences in heart functions. Lastly, statistical tests comparing mean optimal parameter values from resting condition vs pharmacological stress are studied to verify and quantify the effects of dobutamine and glycopyrrolate to the cardiovascular system.
本研究开发了一种包含心房、心室、静脉和动脉的血流动力学模型，该模型可根据实验结果进行校准。它是一种风箱模型，在流向心房的血流中纳入了非稳态伯努利效应。该模型由以各腔室血容量为状态变量的常微分方程表示，并且它展示了使用电导而非电阻来捕捉不漏血心脏瓣膜的效应。实验结果是来自20名年轻受试者（其中一半为女性）和20名老年受试者（其中一半为女性）在静息状态、变力应激（多巴酚丁胺）和变时应激（格隆溴铵）期间的血容量数据。该模型经过校准以符合4个不同层面的数据和生理学发现。首先，设计了一种优化程序来寻找能使模型体积曲线与心房和心室血容量数据良好拟合的模型参数值。使用患者特定信息来获取初始参数值作为优化的起点。此外，模型压力曲线必须呈现出实际的行为。其次，进行参数自抽样以确定最优参数的可靠性。第三，检验比较年轻与老年受试者以及女性与男性的平均最优参数值的统计测试，以支持并呈现心脏功能方面与年龄和性别相关的差异。最后，研究比较静息状态与药物应激下平均最优参数值的统计测试，以验证并量化多巴酚丁胺和格隆溴铵对心血管系统的影响。
