Stergiopulos N, Westerhof B E, Westerhof N
Biomedical Engineering Laboratory, Swiss Federal Institute of Technology, Lausanne, Switzerland.
Am J Physiol. 1998 Apr;274(4):H1386-92. doi: 10.1152/ajpheart.1998.274.4.H1386.
We propose a new method to derive aortic pressure from peripheral pressure and velocity by using a time domain approach. Peripheral pressure is separated into its forward and backward components, and these components are then shifted with a delay time, which is the ratio of wave speed and distance, and added again to reconstruct aortic pressure. We tested the method on a distributed model of the human systemic arterial tree. From carotid and brachial artery pressure and velocity, aortic systolic and diastolic pressure could be predicted within 0.3 and 0.1 mmHg and 0.4 and 1.0 mmHg, respectively. The central aortic pressure wave shape was also predicted accurately from carotid and brachial pressure and velocity (root mean square error: 1.07 and 1.56 mmHg, respectively). The pressure transfer function depends on the reflection coefficient at the site of peripheral measurement and the delay time. A 50% decrease in arterial compliance had a considerable effect on reconstructed pressure when the control transfer function was used. A 70% decrease in arm resistance did not affect the reconstructed pressure. The transfer function thus depends on wave speed but has little dependence on vasoactive state. We conclude that central aortic pressure and the transfer function can be derived from peripheral pressure and velocity.
我们提出了一种新方法，通过时域方法从外周压力和速度推导主动脉压力。外周压力被分离为其正向和反向分量，然后这些分量以延迟时间进行移位，该延迟时间是波速与距离的比值，再将它们相加以重建主动脉压力。我们在人体全身动脉树的分布式模型上测试了该方法。根据颈动脉和肱动脉的压力及速度，主动脉收缩压和舒张压的预测误差分别在0.3 mmHg和0.1 mmHg以及0.4 mmHg和1.0 mmHg以内。中心主动脉压力波形也能根据颈动脉和肱动脉的压力及速度准确预测（均方根误差分别为1.07 mmHg和1.56 mmHg）。压力传递函数取决于外周测量部位的反射系数和延迟时间。当使用对照传递函数时，动脉顺应性降低50%对重建压力有相当大的影响。臂部阻力降低70%对重建压力没有影响。因此，传递函数取决于波速，但对血管活性状态的依赖性很小。我们得出结论，中心主动脉压力和传递函数可以从外周压力和速度推导得出。
