Relationship between endothelial function of micro- and macrocirculation in patients with peripheral arterial disease

In the pathogenesis of peripheral arterial occlusive disease (PAD), different risk factors of atherosclerosis are involved which stimulate the development of the functional and morphological deterioration of vessel walls in macro- and microcirculation. The endothelial dysfunction (ED) of macrovessels has been proven, however, data on ED in microcirculation are sparse. Therefore, we have studied the relationship between micro- and macrocirculation in PAD patients.

The study included 85 participants: 30 patients had PAD without diabetes mellitus, 30 patients had PAD and diabetes mellitus type 2, and 25 were healthy controls. Flow-mediated dilation (FMD) and endothelium-independent dilation (NMD) were studied as markers of macrocirculation, while ED of microcirculation was determined by peripheral arterial tonometry, which enabled calculation of the reactive hyperemia index (RHI). Simultaneously, the augmentation index (AI) as a measure of arterial stiffness was calculated.

In comparison to healthy subjects, PAD patients had reduced FMD (5.7 ± 1.3 % vs. 10.0 ± 2.4 %, p < 0.001) and significantly decreased NMD (11.0 ± 2.9 % vs 23.0 ± 9.0 %, p < 0.001). Low-flow-mediated constriction was not significantly different between the groups. In both groups of patients, RHI was significantly lower than in the controls (1.75 ± 0.45 vs. 2.05 ± 0.54, p = 0.033). Furthermore, AI as an indicator of arterial stiffness was significantly higher in patient groups than in controls. However, there were no significant differences between the groups of PAD patients with and without diabetes mellitus in indicators of the functional capability of micro- and macrocirculation. An interrelationship was shown between risk factors and both FMD and NMD. Significant correlation was also found between FMD and RHI, as was a borderline correlation between FMD and AI.

In PAD patients with and without diabetes, the functional capability of the entire arterial system is deteriorated. These patients have ED in micro- and macrocirculation, as well as increased arterial stiffness.
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