Angioscan Electronics AngioScan-01, User Manual, Page: 42 / 119

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AngioScan Medical Tests
2002, 2003]. Currently, PWV is the "gold standard" of the assessment of vascular wall elasticity
[Laurent et al.
2006].
It was shown large prospective studies that an increase in pulse wave velocity is significantly associated
with an increased risk of total and cardiovascular mortality in the elderly [Meaume et al.
2001; Sutten,
Tyrrell et al. 2005; Mattace-Raso et al. 2006], patients with hypertension [Laurent et al. 2001, 2003;
Boutouyrie et al. 2002], type 2 diabetes mellitus [Cruickshank et al. 2002], kidney disease [Blacheratal.
1999], as well as in the general population [Willum-Hansen et al. 2006].
The stiffness parameters of the vascular wall, such as the pulse wave velocity and the augmentation
index, are among the tests used when evaluating subclinical organ damage in hypertension, as well as
in the prognosis of these patients [Laurent et al.
2006].
4.1.4.9 RI - Reflection Index
Reflection Index (RI) is used to assess the contribution of the reflected component to the pulse wave.
This indicator is defined as the ratio of the maximum amplitude of the reflected wave to the maximum
amplitude of the direct wave, expressed as a percentage:
Index reflection = (B / A) x 100%, where
B - the maximum amplitude of the reflected wave;
A - the maximum amplitude of the direct wave.
In contrast to the rigidity index, which characterizes the state of the main resistive blood vessels such
as the aorta and its branches, the reflection index is used to assess the tone of the small muscular
arteries.
The reflection index can be useful in determining the spasm of small peripheral arteries, as a
component of the pathogenesis of hypertension and chronic heart failure. The normal values of the
reflection index do not exceed 30%. When the reflection index rises to 50% or higher, it is indicative of a
high tone of small muscular arteries.