Microcirculation in venous ulcers and the surrounding skin: findings with capillary microscopy and a laser Doppler imager.

Background: To obtain more information about microcirculatory disturbances in venous ulcers, we studied their laser Doppler flux images and capillary densities.
Materials and Methods: On photographs of venous ulcers and the adjacent skin of 17 patients, four regions of interest were marked: one non-granulation tissue area (NGTA) within the venous ulcer, one granulation tissue area (GTA) within the ulcer, one adjacent skin area (ASA) and one distant skin area (DSA). Within these four regions the average laser Doppler area fluxes and capillary densities were determined for each patient using a laser Doppler imager and capillary microscopy respectively.
Results: The laser Doppler area flux (mean +/- SD in AU) was significantly lower in NGTA (1.39 +/- 1.12) than in GTA (4.06 +/- 1. 52) or DSA (3.86 +/- 1.54) (P < 0.00001). In addition, the ASA flux (1.95 +/- 1.39) was significantly lower than the GTA or DSA flux (P < 0.0001). Capillary density (capillaries per mm2) in NGTA (0.82 +/- 1.98) was significantly lower than that in GTA (6.00 +/- 2.55), ASA (13.88 +/- 5.16) or DSA (10.29 +/- 3.41) (P < 0.0001). In addition, the capillary density of ASA was significantly higher than that of GTA or DSA (P < 0.05).
Conclusion: The four areas showed the following characteristics: NGTA, low laser Doppler area flux and lowest capillary density (possible sign of ulcer area without healing tendency); GTA, high laser Doppler area flux and second lowest capillary density (possible sign of wound healing); ASA, low laser Doppler area flux and highest capillary density (possible sign of healing process nearly completed; scar); DSA, high laser Doppler area flux and second highest number of capillaries (sign of microcirculation of chronic venous disorder).