Techniques for Studying Arterial Elastic Properties

To the Editor:I applaud the effort of Rietzchel and colleagues1 to compare two techniques in wide use for studying arterial elastic properties. This is a study long in need of performance because of the controversial claims in the literature relating to the theory of systolic and diastolic waveform analysis. As we had anticipated and predicted,2 a reasonably good correlation was observed between the C2 measured by diastolic pulse wave analysis using a modified Windkessel analysis and late systolic augmentation index assessed using a transfer function previously described. The values from both of these techniques apparently relate, at least in part, to reflected waves from the peripheral small arteries. The augmentation index is also critically dependent on large artery pulse wave velocity that accounts for appearance of the reflected wave at the root of the aorta in late systole. The C2 also may have some dependency on large artery elasticity, but fortunately an independent assessment of this large artery elasticity is also available from the calculation of C1 in the modified …