[Microcirculatory evaluation of the early diabetic foot syndrome using laser doppler]

Recognition of early microcirculatory disturbances in feet of diabetics may facilitate the pathogenic interpretation of the diabetic foot syndrome, selection of the patients at risk of developing clinical problems and serve as the base for designing the preventive measures. This could be particularly true in diabetics with peripheral neuropathy. Therefore the study aimed at the assessment of functional parameters of the foot microcirculation in IDDM patients presenting signs of peripheral neuropathy but without any symptoms of the diabetic foot syndrome was undertaken. For comparison 20 IDDM subjects with the signs of peripheral neuropathy and 10 IDDM subjects without this complication were studied both clinically and metabolically. All of them underwent the examination of microcirculation of the feet with the use of Laser Doppler Flowmeter. The parameters measured were: resting blood flow, post-occlusive, hyperemic response, flow change after heating to 44 degrees C and the flow on dependency. In IDDM subjects with peripheral neuropathy the following functional microcirculatory abnormalities were found: delay and decrease in post-occlusive, hyperemic response (4.5 +/- 1.8 s in neuropathic vs 0.5 +/- 2.4 s in non-neuropathic IDDM patients), decrease of the peak flow (36 +/- 7.0 PU in non neuropathic vs 18 +/- 5.0 PU in neuropathic IDDM patients) and also impairment of the response of the skin flow to focal heating peak flow at 44 degrees C (48 +/- 7.0 PU vs 12 +/- 3.0 PU in non neuropathic IDDM patients). Also the venoarteriolar reflex measured as the ratio of resting to standing flow in the feet skin was significantly decreased (80% in non-neuropathic versus 35% in neuropathic IDDM patients).

Laser Doppler Flowmetry discovers the very early functional abnormalities in the microcirculation of the skin in the feet of IDDM with peripheral neuropathy, when none of the typical symptoms of the diabetic foot syndrome is present. It points to the significance of the relation between neuropathic and microcirculatory disturbances in the early pathogenesis of diabetic foot syndrome.