Microcirculatory dysfunction in chronic venous insufficiency (CVI)

The elevated ambulatory pressure in the peripheral venous system of chronic venous insufficiency (CVI) patients manifests itself not only in the form of disturbed macrocirculation but also and particularly in microangiopathic charges. For this reason, it is closely correlated with trophic disorders of the skin and can ultimately lead to ulceration. Using microcirculation r esearch techniques; we are able to provide clear evidence of a typical micr oangiopathy in chronic venous insufficiency. Fifty CVI patients in Widmer s tages I; II; and III were examined. with fluorescence video microscopy, int ravital video capillaroscopy, transcutaneous; oxygen partial pressure measu rement, TcpO(2) and laser Doppler flowmetry;. The effects of compression th erapy!; with individually fitted compression stockings on capillary morphol ogy; were studied over a period of 4 weeks in 20 CVI patients in Widmer sta ges I and II. The capillary pressure was measured during simulated muscle c ontraction using a servo-null micropressure system We periodically drew blo od from the dorsalis pedis vein and a brachial vein of 11 healthy test pers ons and 8 patients with stage III CVI during experimental venous hypertensi on in order to evaluate the expression pattern of leukocyte adhesion molecu les involved in inflammation: LFA-1 (CD11a), Mac-1 (CD11b), p150,95 (CD11c) , CD18, VLA-4 (CD49d), and L-selectin (CD62L). In the same patients, me use d immunohistochemical methods to examine clinically unaffected skin and the skin ne,near an ulcer; focusing on the adhesion molecules ICAM-1, VCAM-1 a nd E-selectin. The microangiopathic changes observed with worsening clinica l symptoms include a decrease in the number of capillaries, glomerulus-like changes in capillary morphology; a drop in the oxygen content (tcpO(2)) of the sl;in, increased permeability) of the capillaries to low-molecular-wei ght substances, increased laser Doppler flux reflecting elevated subcutaneo us flow; and diminished vascular reserve. These microangiopathic changes wo rsen in linear proportion to the clinical severity of chronic venous insuff iciency In patients with venous ulcerations the baseline expression of LFA- 1 and VLA-4 on lymphocytes, Mac-1 expression sri the myeloid cell line., an d L-selectin expression on all three cell Lines was not significantly diffe rent from that in healthy controls. During orthostatic stress; there was a significant reduction in the ex; expression of L-selectin in blood cells co llected at foot level in the controls (p = 0.002), but not in the patients. Clinical improvement by compression therapy; nias accompanied by art incre ase in the number of nutritive capillaries; while the diameter of the capil laries and the dermal papillae was reduced. When ulcers healed in a short p eriod (<6 weeks), we observed a concomitant increase in the number of capil laries (p < 0.05). Microangiopathy appears before trophic disorder of the s kin develop. Even trophically normal skin areas may have dilated nutritive capillaries, an early sign of disturbed skin perfusion. These changes repre sent a plausible explanation for the development anti to recurrency tendenc y of venous ulcers. The reduced expression of lymphocytic L-selectin in hea lthy controls during the orthostatic stress test may be an indication that the cells are activated by venous stasis. Clinically effective therapeutic measures improve the impaired microcirculation of the skirt in the ankle ar ea.