Assessment of Local Heating Effect on the Cutaneous Microcirculatory Vasodilatation

The skin provides a conveniently accessible site to assess the peripheral microvascular function which may be used as an early index of allover cardiovascular system. In the study, the laser Doppler flowmetry (LDF) was applied to investigate the vasodilatation of microcirculation on the foot bottom during a local heating protocol in 21 healthy participants. The temperature was heated up to 44 °C in one minute and maintained such temperature through the 30-min heating period. Both a 10-min record of LDF signals during the baseline and a 30-min record during the heating period were registered and then analyzed using the wavelet transform. For the 21 participants, the amplitudes of the initial peak [208 ± 64 perfusion unit (PU)] and the plateau (279 ± 80 PU) of the LDF signals were significantly higher during the local heating period than the baseline (85 ± 25 PU). Meanwhile, the composite vasodilatation indexes for the initial peak and the plateau were 154 ± 65 and 239 ± 93%, respectively. Also found was a significant decline in the spectral power density percentage associated with the endothelial nitric oxide-dependent metabolic activity band during the heating period, as compared with the baseline. Those findings may help to assess the skin microcirculation dysfunction in patients with diabetes or hypertension in future clinical applications.