Abstract
Microvascular function has been assessed by determining the rhythmic oscillations in blood flow induced by the vasomotion of resistance vessels. Although laser-Doppler flowmetry (LDF) allows simple, non-invasive evaluation of this flow-motion in the cutaneous microcirculation, the temporal and spatial reproducibility of such assessments remains unclear.In the present study, we investigated cutaneous flow-motion in three consecutive years in eight skin regions using LDF in six healthy young volunteers. The characteristic flow-motion frequency was determined using fast-Fourier transformation. Additionally, in two years a more traditional measure of microvascular reactivity, postocclusive reactive hyperemia (PORH) was evoked in the forearm after transient brachial artery occlusion (1-2-3 min) induced by cuff inflation.Well-defined flow-motion was found in six regions showing significant differences in frequency: the highest flow-motion frequency was found in the frontal and temporal regions (8.0 ± 1.1 and 8.5 ± 1.0 cycles/min, cpm, respectively, mean ± SD) followed by the scapular, infraclavicular and coxal regions (7.5 ± 1.3; 6.7 ± 1.1 and 6.5 ± 1.2 cpm, respectively). The lowest, stable flow-motion was found in the posterior femoral region (5.5 ± 1.0 cpm), whereas flow-motion was detectable only sporadically in the limbs. The region-dependent flow-motion frequencies were very stable within individuals either between the body sides, or among the three measurements, only the infraclavicular region showed a small difference (114 ± 17%∗, % of value in 1st year; ∗P < 0.05). However, PORH indices differed after 2-3 min occlusions significantly in consecutive years.We report that flow-motion frequencies determined from LDF signals show both region-specificity and excellent intra-individual temporal and spatial reproducibility suggesting their usefulness for non-invasive follow-up of microvascular reactivity.
Highlights
Microvascular dysfunction is a common denominator in a number of chronic systemic diseases playing a pivotal role in the development of organ damage [9, 14, 19]
We report that flow-motion frequencies determined from laser-Doppler flowmetry (LDF) signals show both region-specificity and excellent intra-individual temporal and spatial reproducibility suggesting their usefulness for non-invasive follow-up of microvascular reactivity
The major novel findings of the present study are the following: 1) low-frequency flow-motion is a region-dependent feature of the human cutaneous microcirculation with a clear spatial pattern; 2) flow-motion frequency shows better intra-individual temporal stability than the postocclusive reactive hyperemia (PORH) index in healthy young volunteers
Summary
Microvascular dysfunction is a common denominator in a number of chronic systemic diseases playing a pivotal role in the development of organ damage [9, 14, 19]. In contrast to relative flow changes in response to various stimuli that bear organ-specific features, the spectral analysis of the LDF signal reveals rhythmic oscillations in CuBF of different frequencies representing flow-motion [6, 20] This flow-motion stems from the vasomotion of resistance vessels, and the presence and degree of this vasomotion in the respective frequency ranges have been suggested to provide information on autonomic vasomotor tone, vascular smooth muscle function, and perhaps most importantly on the functional integrity of the microvascular endothelium [20]. There are numerous unresolved issues concerning the applicability of the study of CuBF flow-motion as a potential index of microvascular health It is unclear how many times such a test should be performed to sufficiently characterize the functional status of the microvessels. To be able to compare the stability of our flow-motion frequency data with that of a traditional microvascular response, postocclusive reactive hyperemia (PORH) of the forearm CuBF was determined
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call