Laser Doppler Flowmetry in Assesment of Local Mechanisms of Microcirculation in Patients with Diabetes Mellitus Type 2 Complicated by Diabetic Foot Syndrome and Chronic Kidney Disease
Purpose. To analyze changes in the low-frequency part of the spectrum of the laser Doppler flowmetry (LDF) signal in patients with diabetic microangiopathy and to identify their correlations with glomerular filtration rate. Materials and methods. The study included 42 patients (20 men and 22 women) with type 2 diabetes mellitus and diabetic foot syndrome, aged 58-77 years, with chronic kidney disease of the stage C3- C4. Each patient performed the LDF registration followed by spectral analysis and assessment of its indicators with the estimated glomerular filtration rate. The features of microcirculation disorders were revealed on the base of it. Results. There were no significant correlations between the glomerular filtration rate and the amplitudes of myogenic and neurogenic flux motions (p>0.05). However, there was a significant positive correlation between the contribution of myogenic flux motions to the low-frequency range and glomerular filtration rate; and a negative one - for the contribution of neurogenic flux motions (p<0.05). In six observations, there was a tendency to decrease of the amplitude of endothelial flux motions as the glomerular filtration rate decreased. Conclusion. In the course of this study, a new technique for assessing the contribution of the low- frequency range components was tested. In patients with chronic kidney disease of the C3-C4 stage, decrease of the glomerular filtration rate correlated with the decrease of the contribution of myogenic flux motions and increase of the contribution of neurogenic flux motions to the total power of the low-frequency part of the amplitude-frequency spectrum of the LDF signal. These changes can be explained by damage to the smooth muscle layer of the wall of arterioles and venules with damage to pacemaker myocytes and violation of the basal vascular tone.