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

Abstract

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).

Healing process of venous ulcers: the role of microcirculation

“…Are these changes similar to those obtained in different ulcer areas at the same time of observation as described earlier (6–8)?…”

“…Once venous ulcers have formed, initially they appear pale, which is indicative of the absence of GTA (Figure 1A, I). The absence of GTA implies that these areas of venous ulcers lack clinical and histological signs of wound healing at this time (6–8). In terms of microcirculation, this late stage of ulcer formation or early phase of wound healing is characterised by low but still detectable subpapillary perfusion (1·35; 0·71–1·83 AU), as revealed by an LDPI.…”

“… Which dynamic changes in subpapillary and nutritive microcirculation accompany the three consecutive clinical healing stages of venous ulcers? This was investigated by laser Doppler perfusion (LDP) imaging and capillary microscopy. What is the pathophysiological meaning of such changes in microcirculation during the process of wound healing? Are these changes similar to those obtained in different ulcer areas at the same time of observation as described earlier (6–8)? …”

“…In the earlier studies, it was shown that microcirculation within and adjacent to ischaemic and venous ulcers is marked by local differences, depending on the stage of wound healing. In these studies, three consecutive stages of wound healing have been described: ulcer areas without any granulation tissue (GTA) (no detectable wound healing process), ulcer areas with a GTA (active healing process) and scars at the site of the former ulcers (completed healing) (2,6–8). However, to our knowledge, no studies have focused on the dynamic changes in the microcirculation within an area of interest during the process of ulcer healing.…”

“…In the earlier studies, it was shown that microcirculation within and • in this study, we repeatedly examined 10 patients with venous ulcers starting from the stage of no detectable wound healing (no GTA) to active wound healing (appearance of GTA) until the healing process had been completed (scar tissue) • we investigated area-dependent changes in the microcirculation in a series of carefully pre-defined areas within each of the 10 ulcers • chronic venous insufficiency was caused by a postthrombotic syndrome in one subject and due to insufficient epifascial veins in the remaining nine patients • clinically these results validate using LPDI and CD for assessing healing of venous ulcers • together, they have also provided a basis for quantifying the extent of healing (tissue repair, perfusion status depending on the skin layer rate and time required for healing etc) • poor nutritive perfusion is the underlying reason for the development of local necrosis and the genesis of venous ulcers • although we did not investigate the presence of trophic lesions in the skin unaffected by arterial or venous disturbances, the similarity in the healing of venous and ischaemic ulcers leads us to the conclusion that the process of wound healing is independent from the underlying cause • our study showed that an early increase in the subpapillary (laser Doppler) flux plays a major role in the healing process of venous ulcers • in addition, the CD in the nutritive network is also increased • these changes are predominantly found in the stage of GTA • the most recent research has been focusing on developing functional model(s) for wound healing kinetics, expressed in physiological terms, which could provide a surrogate marker for predicting the result at an arbitrarily selected point in time • however, more research is needed to create a functional model that would accurately fit the entire process of healing • thus, further studies of the ulcer healing process in general, and its association with identified factors underlying microcirculation, would be of interest when further exploring the possibilities of improving the prognosis • nevertheless, our results suggest that LDPI and CD themselves, or in combination with other methods such as transcutaneous oxygen measurements, can be useful tools for predicting wound healing outcome, and developing a model of microcirculatory changes in the ulcers with respect to the stages of healing • such knowledge will contribute to improving clinical assessment of healing tendency of defects of venous origin adjacent to ischaemic and venous ulcers is marked by local differences, depending on the stage of wound healing. In these studies, three consecutive stages of wound healing have been described: ulcer areas without any granulation tissue (GTA) (no detectable wound healing process), ulcer areas with a GTA (active healing process) and scars at the site of the former ulcers (completed healing) (2,(6)(7)(8). However, to our knowledge, no studies have focused on the dynamic changes in the microcirculation within an area of interest during the process of ulcer healing.…”