A study of the mechanical and microcirculatory properties in skin subject to venous ulceration

In chronic venous insufficiency (CVI), numerous changes occur in the skin consequent to impaired venous flow. These changes which include oedema, result in the skin being prone to ulceration. The cause of ulceration is not clear, diflerent hypotheses were proposed, but none accepted. Unrelieved oedema is associated with impaired healing. Cutaneous oedema of the lower extremities is produced by a disturbance in the state of near equilibrium that involves capillaries, lymphatics and interstitium. A change in the cutaneous properties is expected with the presence of oedema. The aim of this work was to investigate changes in the cutaneous mechanical and microcirculatory properties in oedematous tissues. Non-invasive durometry, uniaxial extensometry and laser Doppler flowmetry were chosen for the measurements. Durometry and extensometiy were found reliable. In controls, measurements demonstrated regional variations in the mechanical properties, and differences with age. In the elderly, microvascular response to a minor challenge was impaired, as was the postural vasoconstrictive response. Studies on patients with CVI (with frank ulcers and without) showed an increase in hardness index and a reduction in both extensibility and relaxation indices. Microvascular response to a minor challenge was impaired but an intact postural vasoconstrictive response was foimd.