Abstract

Purpose of Study: Non-invasive laser Doppler fluximetry
(LDF) and laser Doppler imaging (LDI), combined with iontophoresis,
have been used to study the microcirculation in a
range of clinical conditions including lower limb venous disease.
A prerequisite for an accurate measurement tool is that
it is reproducible. However, there is currently no literature
with respect to the reproducibility of LDF and LDI combined
with iontophoresis in the lower limb (in general) and in the
upright position (in specific). Furthermore, the two techniques
have been used interchangeably by researchers and
the association between these two different measurement
methods has not been explored, nor have the factors that
affect them been well described. Thus the aim of this study
was to determine the reproducibility of LDF and LDI with
iontophoresis in the lower limb and investigate factors that
influence their clinical application. Procedures: Cutaneous
microvascular responses in the lower limb were measured in
the supine and standing positions using LDF and LDI combined
with iontophoretic administration of endothelial-dependent
(acetylcholine, ACh) and -independent (sodium nitroprusside) vasodilators in 25 patients with uncomplicated
isolated superficial venous incompetence (ISVI) and 26
healthy controls. Results: Maximum perfusion had the best
reproducibility assessed by LDF (CV 20.5–24.3%) and LDI
(15.8–17.6%). Both techniques were positively influenced by
iontophoretic dose (e.g. p = 0.0001 for LDF) and the use of
vasodilator agents (e.g. p = 0.0001 for LDF), but negatively
influenced in the standing position and/or in the presence
of ISVI (p = 0.0016 and 0.045, respectively, for LDF). There was
a statistically significant positive relationship between the
two techniques, for example ACh maximum perfusion versus
LDF ACh maximum perfusion (r = 0.404, p = 0.016). Conclusions:
Both techniques are reproducible, in line with similar
studies undertaken in other areas of the human body,
and provide useful information for the study of the lowerlimb microcirculation. Direct comparison between techniques based on absolute numbers should be avoided and
the technique choice should be based on individual study
needs.