Background: Vasomotion is the slow rhythmic contraction of the smooth muscles of arterioles, metarterioles, and precapillary sphincters. It improves rheologic function of capillary blood flow and guarantees cellular nutrition and oxygen supply. Oxygen supply to the skin by blood can be quantified by measuring oxyhemoglobin concentration and hemoglobin oxygen saturation. Material and methods We examined the consequences of disturbed vasomotion in 51 patients with chronic venous insufficiency (CVI) and 36 healthy control subjects. With the subjects supine as well as during orthostasis, intracutaneous changes in concentration of total hemoglobin and oxyhemoglobin and in oxygen saturation of hemoglobin were measured over 120 seconds with reflection spectrophotometry. Periodic variations in measured parameters were analyzed with modified digital Fourier transformation.
Results: In the supine position both groups demonstrated the same vasomotion frequency. During orthostasis, vasomotion frequency in patients with CVI decreased significantly, from 7.4 +/- 2.2 cpm to 5.4 +/- 2.5 cpm, whereas vasomotion frequency in control subjects increased significantly, from 4.5 +/- 1.6 cpm to 8.8 +/- 2.5 cpm. Correspondingly, hemoglobin saturation and oxyhemoglobin concentration in patients with CVI patients exhibited a significantly stronger decrease compared with that in control subjects.
Conclusion: The failing increase in vasomotion frequency during standing leads to longer dilation of the distal vessels per time unit, with increase in hematocrit. This might favor formation of microthrombi in the capillaries and further perimalleolar tissue damage in CVI.