Background: Leg telangiectasias are visible, ectatic dermal arteriols, capillaries, or veins with a diameter of 0.1-1 or 2 mm. Their origin is still not known and different opinions have been published.
Objective: In our study we were interested in the different colors of telangiectasias and we wanted to demonstrate whether a difference in blood gases is causing the difference in color between red and blue telangiectasias.
Methods: We measured a capillary astrup in 20 patients, who had red as well as blue telangiectasias on the lower limb. Therefore, we took two samples, one of a red and one of a blue telangiectasia. By this we measured the oxygen saturation and the carbon dioxide concentration of the samples. Furthermore, we introduced the appearance of telangiectasias in two rather newly developed techniques, such as high-frequency 20- and 50-MHz ultrasound and laser Doppler perfusion imaging (LDPI).
Results: Red telangiectasias of all 20 patients had an average oxygen concentration of 5.9 kPa, (range, 3.94-7.46 kPa); their average CO2 concentration was 5.45 kPa (range, 4.54-7.06 kPa). Blue telangiectasias had an average oxygen concentration of 5.11 kPa (range, 3.12-7.0 kPa); their average CO2 concentration was 6.07 kPa (range, 5.38-7.36 kPa). Statistically work-up with a paired student's t-test showed a higher oxygen saturation of the red telangiectasias and a higher carbon dioxide concentration of the blue vessels.
Conclusion: As telangiectasias are assumed to be located in the capillary bed, the reason for differences in oxygenation could possibly be found in underlying physiological and anatomical principles of the capillary loops with the red telangiectasia representing the arterial loop of the capillary and the blue telangiectasia representing the venous loop of the capillary. With high frequency ultrasound and LDPI it is possible to get useful information for finding the underlying feeder veins, which "feed" the superficial telangiectasias. Injecting into the nutritional vessel telangiectases can potentially decrease the number of side effects and, may reduce the number of necessary injections.