Microcirculation disturbances in patients with venous ulcer before and after healing as assessed by laser Doppler flux-metry

BACKGROUND: We studied whether a characteristic pattern of laser Doppler flux (LDF) could be identified in perimalleolar skin of patients with venous ulcer before and after ulcer healing. METHODS: Nine subjects with venous ulcer that healed after conservative treatment in 1-6 months and nine healthy persons were included in the study. Microcirculation investigations of laser Doppler flux (LDF) were carried out before and after ulcer healing at rest, upon arterial occlusion, during thermal stimulation and during experimental venous hypertension. RESULTS: Resting LDF expressed as median and range (in arbitrary perfusion units) was significantly higher in patients with venous ulcer in comparison to healthy subjects: 60.6 (40.2-156.5) vs. 9.2 (6.5-19.5), p=0.008. During thermal stimulation and during postischemic reactive hyperemia, absolute values of LDF were slightly but significantly higher in patients with venous ulcer than in healthy subjects, but indices of hyperemic reactivity were very low in patients (median postischemic LDF increase to 101.8 vs. 450.0% in healthy controls, p=0.008; and thermally induced LDF increase to 125.5 vs. 881.5% in healthy controls, p=0.008. Experimental venous hypertension (cuff pressure 40 and 70 mmHg, respectively) led to an equally pronounced relative reduction of LDF in healthy persons as in patients with venous ulcer before and after ulcer healing, but the absolute values of flow remained about six to seven times higher in patients when compared to healthy subjects. Hyperemic reactivity and venoarteriolar response did not change after ulcer healing. CONCLUSIONS: Elevated basal LDF and preserved maximal LDF during reactive hyperemia were found in perimalleolar skin of patients with venous ulcers that eventually healed. The relative venoarteriolar response was preserved in spite of elevated absolute values of LDF during experimental venous hypertension. These hemodynamic characteristics remained unchanged after epithelialization of venous ulcers.