Previous attempts to use photoplethysmography (PPG), tissue reflectance oximetry (TRO), Laser Doppler Flowmetry (LDF), etc. for dynamic evaluation of microvascular complications of diabetes mellitus (DM) have not led to success. We propose new method – incoherent optical fluctuation flowmetry (IOFF), which additionally allows to implement PPG and TRO within IOFF probe. Current study was aimed on the first validation of combined diagnostic IOFF-TRO-PPG technique for microcirculation assessment in patients with DM.
Oscillometric tonometry, IOFF, PPG and TRO techniques were combined in single device and used to assess a set of 7 parameters of central and peripheral hemodynamics. Pilot measurements were conducted on 18 DM patients (8 with diabetic retinopathy and 10 without it) and 18 healthy volunteers. To consider influence of peripheral and central hemodynamic factors (heart rate, blood pressure, arterial stiffness, blood flow, etc.) in assessment of skin microvasculature functional state (including endothelial and neurogenic regulation), we calculated complex diagnostic criterion (DC) as the weighted function of all measured quantities.
DC in the control group was -0.5±1.9, in DM patients without retinopathy – -3.1±1.1, in DM patients with retinopathy – -4.9±1.5. ANOVA with LSD post-hoc analysis showed all groups were pairwise different. DC parameter allowed us to classify patients into these three groups with 72.2% accuracy.
The device, created on the basis of IOFF, allows to perform comprehensive assessment of peripheral hemodynamics and to reveal microcirculation disorders of various genesis. In long term, the proposed technology can be used to assess DM complications risk and as additional endpoint in DM management.