Lillie Jeffrey S, Liberson Alexander S, Mix Doran, Schwarz Karl Q, Chandra Ankur, Phillips Daniel B, Day Steven W, Borkholder David A
Rochester Institute of Technology, Rochester, NY, USA.
University of Rochester, Rochester, NY, USA.
Cardiovasc Eng Technol. 2015 Mar;6(1):49-58. doi: 10.1007/s13239-014-0202-x. Epub 2014 Dec 6.
Pressure wave velocity (PWV) is commonly used as a clinical marker of vascular elasticity. Recent studies have increased clinical interest in also analyzing the impact of heart rate, blood pressure, and left ventricular ejection time on PWV. In this article we focus on the development of a theoretical one-dimensional model and validation via direct measurement of the impact of ejection time and peak pressure on PWV using an in vitro hemodynamic simulator. A simple nonlinear traveling wave model was developed for a compliant thin-walled elastic tube filled with an incompressible fluid. This model accounts for the convective fluid phenomena, elastic vessel deformation, radial motion, and inertia of the wall. An exact analytical solution for PWV is presented which incorporates peak pressure, ejection time, ejection volume, and modulus of elasticity. To assess arterial compliance, the solution is introduced in an alternative form, explicitly determining compliance of the wall as a function of the other variables. The model predicts PWV in good agreement with the measured values with a maximum difference of 3.0%. The results indicate an inverse quadratic relationship ([Formula: see text]) between ejection time and PWV, with ejection time dominating the PWV shifts (12%) over those observed with changes in peak pressure (2%). Our modeling and validation results both explain and support the emerging evidence that, both in clinical practice and clinical research, cardiac systolic function related variables should be regularly taken into account when interpreting arterial function indices, namely PWV.
压力波速度（PWV）通常用作血管弹性的临床指标。最近的研究增加了临床对分析心率、血压和左心室射血时间对PWV影响的兴趣。在本文中，我们专注于开发一个理论一维模型，并通过使用体外血流动力学模拟器直接测量射血时间和峰值压力对PWV的影响来进行验证。针对充满不可压缩流体的顺应性薄壁弹性管，开发了一个简单的非线性行波模型。该模型考虑了对流流体现象、弹性血管变形、径向运动和管壁惯性。给出了PWV的精确解析解，其中包含峰值压力、射血时间、射血量和弹性模量。为了评估动脉顺应性，以另一种形式引入该解，明确确定管壁顺应性作为其他变量的函数。该模型预测的PWV与测量值吻合良好，最大差异为3.0%。结果表明射血时间与PWV之间呈反二次关系（[公式：见正文]），射血时间导致的PWV变化（12%）比峰值压力变化导致的PWV变化（2%）更显著。我们的建模和验证结果既解释又支持了新出现的证据，即在临床实践和临床研究中，在解释动脉功能指标即PWV时，应定期考虑与心脏收缩功能相关的变量。
