Pressure wave propagation in a multibranched model of the human upper limb

Abstract

The influence of the large arteries and the peripheral load on pressure wave propagation in the human upper limb was investigated in an anatomically realistic multibranched model based on linear transmission theory. To mimic vascular changes seen in life, the viscoelastic properties of large arteries and the peripheral load properties (represented as modified windkessels) were altered as follows: Young's modulus (from 10.9 x 10(6) to 15.3 x 10(6) dyn/cm2) and phase (from 0 to 15 degrees) of the complex elastance, windkessel time constant (from 0 to 0.6 s), and peripheral reflection coefficient (from 0 to 0.95). The relationship between the central aortic and peripheral radial pressure waveforms was analyzed in the time and the frequency domain. Results indicate that the large arterial properties have less influence (peak systolic pressure changed by 3% and peak of transfer function changed by 29%) than the properties of the peripheral load (systolic pressure changed by 14% and peak of transfer function changed by 74%) on the pressure wave propagation in the upper limb.

Prospective Evaluation of a Method for Estimating Ascending Aortic Pressure From the Radial Artery Pressure Waveform

“…26 These views were supported by noninvasive studies of central (carotid) and upper-limb pressure waves under different conditions 35 and by modeling studies. 18 Formal studies of transfer function between the ascending aorta and upper-limb arteries showed relative consistency, [12][13][14][15]25,36 including studies conducted with NTG used as a vasodilator agent. For the most part, these findings have been confirmed by others [13][14][15] who understandably had initially indicated strong skepticism.…”

“…6,11 The process involved convolution of the radial waveform by a generalized transfer function, which was taken to characterize pressure wave transformation in the upper limb. [12][13][14][15]18 The series of estimated aortic waveforms, together with the series of radial waveforms from which these were derived, were each ensemble-averaged over an 8-second period into a single calibrated waveform.…”

Fourier Analysis of the Envelope of the Ophthalmic Artery Blood Flow Velocity

“…The definite contour of the envelope waveform is composed of primary waves (generated by contraction of the left ventricle) and secondary reflected waves, which interfere with the primary ones. 13,14 Endothelial dysfunction may result in an increase in the tone of small arteries that would reduce oscillatory compliance. 15 Experimental data indicate that aging alters endotheliumdependent relaxation in arteries, 16 and loss of the oscillatory waveform represents an early and consistent finding with aging and hypertension.…”

Editorial Commentary

“…Recently, techniques based on the determination of a pressure transfer function between the radial artery and the aorta have been employed to provide an estimate of central pressure wave reflection. 8 In this issue of Hypertension, Millasseau et al 9 report on the accuracy of employing a generalized transfer function to the radial artery pressure pulse waveform to provide an estimate of the aortic augmentation index. The accuracy of the approach was assessed against data derived directly from the carotid pressure pulse waveform or after application of a transfer function to the waveform.…”