Cardiovascular Journal of Africa: Vol 29 No 3 (May/Junel 2018)

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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 29, No 3, May/June 2018 AFRICA 149
recoil at a maximum rate.18 It has been reported that higher VF
contributes to increased values of plaque score and β-stiffness,
an index representing the stiffness of the vascular wall, which
accelerates atherosclerosis.5 Stiffness of the artery is indicated
by its elastic properties. This observation is consistent with our
finding in which the higher VF group had significantly lower D
and VEI values than those of the lower VF group.
Similar to the higher VF group, the S1 and D velocity peaks
declined in the hypertensive group (Table 2). This might have
been due to the fact that arteries stiffen with age,14,19 since both
groups were older and had VF. Furthermore, the thickening of
the arterial wall, which is caused by VF, could induce high blood
pressure.20
VRI has been demonstrated to be a good index of
cardiovascular risk in hypertensive patients compared to control
subjects.10,21 VRI is linked to reflection characteristics of velocity. 14
This study showed that there were significant differences between
the hypertensive and normotensive groups in both VRI and
RI values. The RI is a well-recognised index for quantifying
changes in CCA.20,22 This index is widely used as an indicator
of peripheral vascular resistance.20 A previous study reported
that RI was higher in severe internal carotid artery stenosis,
compared to a normal carotid artery of patients.22
Limitations of this study are that we used a cross-sectional
approach only, and the three designated VF groups did not
consider gender and age differences. In our current setting, it was
difficult to find a large number of subjects of the same age with
different levels of VF. Further interventional studies on well-
discriminated groups are required to show a distinction between
cause and effect among non-obese subjects.
Conclusion
We found significant differences in BFV among non-obese
subjects with different levels of VF and BP. The study also
supports the alleged association between increasing VF and BP
levels and the development of hypertension.
This study was partly supported by Mediprotech Co, Ltd, Korea, under an
internationally sponsored research grant (SP15-079-0201), and the Ministry
of Higher Education, Malaysia under the fundamental research grant scheme
(FRGS15-204-0445, FRGS17-026-0592), and MyBrain15 postgraduate schol-
arship programme.
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