Spectral analysis of the blood flow in the foot microvascular bed during thermal testing in patients with diabetes mellitus

TL;DR

This study uses laser Doppler flowmetry and wavelet analysis to investigate microvascular blood flow abnormalities in diabetic patients, revealing impaired vasodilation and spectral differences in blood flow oscillations.

Contribution

It introduces a noninvasive method combining thermal testing and spectral analysis to detect early microvascular dysfunction in diabetes mellitus.

Findings

Diabetic patients show impaired vasodilation response.

Spectral properties of blood flow differ in diabetics even at baseline.

Thermal tests reveal group-specific variations in perfusion and spectral features.

Abstract

Timely diagnostics of microcirculatory system abnormalities which are the most severe diabetic complications, is a significant problem of modern health care. Functional abnormalities manifest themselves earlier than the structural one and their assessment is the focus of present-day studies. In this study, the Laser Doppler flowmetry, a noninvasive technique for the cutaneous blood flow monitoring, was used together with local temperature tests and wavelet analysis. The study of the blood flow in the microvascular bed of toes was carried out in control group of 40 subjects, and two diabetic groups differing in the type of diabetes mellitus (17 of DM1 and 23 of DM2). The temperature tests demonstrated that diabetic patients have impaired vasodilation in response to local heating. The study of oscillating components shows a significant difference of the spectral properties even in the basal conditions. Low frequency pulsations of the blood flow associated with endothelial and activities are lower in both diabetes groups as well as the ones connected with cardiac activity. Local thermal tests induce variations both in the perfusion and its spectral characteristics, which are different in the groups under consideration. We assume that the results obtained provide a deeper understanding of pathological processes involved in the progress of microvascular abnormalities due to diabetes mellitus.