[Vasomotor impairment in patients with diabetic neuropathy--evaluation by laser Doppler flowmetry]

Using laser Doppler flowmetry, we evaluated cutaneous microcirculation in 28 patients with diabetic neuropathy and 18 control subjects. Skin blood flow in the hand was significantly reduced in the patients compared with that in age-matched controls. Skin blood flow in the hand of the patients correlated significantly with the amplitude of sensory nerve action potential of the median nerve. Significant correlation was shown in the patients between skin blood flow in the hand and changes in systolic blood pressure on standing from a supine position. However, there was no correlation between skin blood flow in the hand and variation in the R-R interval. These results suggest that the skin blood flow may decrease with the progression of diabetic neuropathy, particularly sympathetic autonomic neuropathy, and that neural control may be an important factor in the regulation of skin blood flow. Cold water immersion test revealed that there was no significant difference in vasoconstrictive response during the cold challenge, while recovery time of vasodilatory response after withdrawal of the thermal challenge was significantly prolonged in the patients as compared with that in the controls. In addition, it is suggested that the patients with a small increase or normal in skin blood flow of the hand may possess abnormalities predominantly in vasoconstrictive tone, whereas the patients with a decrease in skin blood flow of the hand in vasodilatory tone. Consequently, microcirculation in skin of extremities changes under the balance of vasoconstrictive and vasodilatory tones in patients with diabetic neuropathy.(ABSTRACT TRUNCATED AT 250 WORDS)