OCT-based angiography of human dermal microvascular reactions to local stimuli: Implications for increasing capillary blood collection volumes.

Objectives: To measure and compare microvascular responses within the skin of the upper arm to local stimuli, such as heating or rubbing, through the use of optical coherence tomography angiography (OCTA), and to investigate its impact on blood volume collection.

Materials And Methods: With the use of heat packs or rubbing, local stimulation was applied to the skin of either the left or right upper arm. Data from the stimulated sites were obtained using OCTA comparing pre- and post-stimulation microvascular parameters, such as vessel density, mean vessel diameter, and mean avascular pore size. Additionally, blood was collected using a newly designed collection device and volume was recorded to evaluate the effect of the skin stimulation.

Results: Nineteen subjects were recruited for local stimulation study (including rubbing and heating) and 21 subjects for blood drawn study. Of these subjects, 14 agreed to participate in both studies. OCTA was successful in monitoring and measuring minute changes in the microvasculature of the stimulated skin. Compared to baseline, significant changes after local heating and rubbing were respectively found in vessel density (16% [P = 0.0004] and 33% [P < 0.0001] increase), mean vessel diameter (14% and 11% increase) and mean avascular pore size (5% [P = 0.0068] and 8% [P = 0.0005] decrease) after stimulations. A gradual recovery was recorded for each parameter, with no difference being measured after 30 minutes. Blood collection volumes significantly increased after stimulations of heating (48% increase; P = 0.049) and rubbing (78% increase; P = 0.048). Significant correlations were found between blood volume and microvascular parameters except mean avascular pore size under the heating condition.

Conclusions: OCTA can provide important information regarding microvascular adaptations to local stimuli. With that, both heating and rubbing of the skin have positive effects on blood collection capacity, with rubbing having the most significant effect. Lasers Surg. Med. 50:908-916, 2018. © 2018 Wiley Periodicals, Inc.