Microcirculatory disorders and diabetic polyneuropathy relationship evaluation in T2DM. Hypergly-cemia factor in vascular and neurological impairment development

• Suchkova O.V.
• Rudnichenko V.A.
• Gurfinkel’ Yu.I.

Abstract

In this study we applied digital capillaroscopy, vasography, stimulation electromyography methods in exam­ination of patients with different glycemic control.

The aim of the study: to evaluate the correlation between microcirculation parameters, endothelial func­tion parameters and nerves electrical activity changes; to compare them between patients groups of different glycemic control.

Material and methods. All patients (n=161) were divided into three groups according to the level of glycated hemoglobin. The 1^st group (HbA_1c<7%) included 46 patients (men 54%) at the age of 53.15± 8.71 years with an average HbA_1c=6.28±0.46%. The 2^nd group (7<HbA_1c<9%) consists of 64 patients (males 55%), aged 53.6±9.3 years, HbA_1c=7.76±0.50%. The 3^rd group (HbA_1c>9%) presented 51 patients (males 51%) at the age of 53.53±8.54 years with an average HbA_1c 10.45±1.15%. The duration of T2DM in groups is not significantly differ: in the 1^st group was 3.45±3.12 years in the 2^nd group of 5.62±5.34 years and in the 3^rd group of 6.45±6.8 years (p₁=0.08, p₂=0.48).

Patients were performed digital capillaroscopy. It was estimated the capillary coiling, it's polymorphism, the capillary network density, the perivascular zone size, diameters of the arterial, apex, venous capillary depart­ments and the blood cell velocity. It were estimated pulse wave velocity (PWV), endothelial function by vasog­raphy method. We estimated M-response amplitude, excitation propagation speed, the M-response summoning threshold, residual latency, characteristic of F-wave n.suralis, n. peroneus by stimulation electromyography method.

Results. It was founded decreased M-response amplitude of n. suralis to 6.6±2.4 (p₁=0.04) in the 2^nd group in comparison with the 1^st. The excitation propagation speed was also reduced - 37.8±3.35 (p₁=0.03). The prevalence of A-response summoning threshold raising were significantly increased in the 2^nd group, 88% vs 27% in the 1^st group (p₁<0.01). N. peroneus electric activity also revealed significant deviations in the 2^nd group: the A-response amplitude - 4.76±2.89 (p₁=0.03); - 41.8±4.43 (p₁=0.02). The microcirculation parameters were significantLy aLtered in decompensated diabetes patients group. It were founded capiLLary poLy­morphism (p₁=0.02), increased capiLLary coiLing (p₁=0.06), increased remodeLing coefficient (p₁=0.04), identi­fied a trend to narrowing of the arteriaL capiLLary department. PWV was significantLy increased to 9.03±1.7 (p₁=0.02) in the 2^nd group. The comparison of these indicators between the 2^nd and 3^rdgroups aLso showed statisticaL significance. A correLation anaLysis determined the reLationship between fasting gLycemia and HbA_k with aLL the studied parameters of microcircuLation, macrocircuLation and most of the nerves eLectri­caL activity.

MicrocircuLation disorders had LittLe to do with the deveLopment of diabetic poLyneuropathy. It determined on the basis of correLation anaLysis of 161 patients. OnLy one microcircuLation parameter (density of the capiL­Lary network) correLated with eLectromyography parameters: with n. suralis excitation propagation speed (r=0.28, p<0.05), as weLL as its inverse correLation with the presence of n. peroneus M-response summoning threshoLd raising (r=-0.17, p<0.05).

It was found the correLation reLationship between EF and n. suralis f -response ampLitude. It determined statisticaLLy significant correLation of PWV with the foLLowing parameters (p<0.05): n. suralis M-response sum­moning threshoLd raising, n. peroneus excitation propagation speed, and with the presence of n. peroneus Low-ampLitude F-waves and precipitation.

Conclusions. Changes in the stimuLation EMG indices in patients with T2DM confirmed earLy metaboLic axonaL (non-myeLin) disturbances in the nerves that occur even with moderate vioLation of gLycemic controL. Motor neuropathy, compared to sensoriaL, is more pronounced under moderate vioLation of gLycemic controL.

MacrocircuLatory and microcircuLatory disorders are defined in conditions of moderate hypergLycaemia.

ReLationships in the deveLopment of microvascuLar and neuroLogicaL disorders are aLmost not identi­fied except of the capiLLary network density that correLates with n. suralis excitation propagation speed and with n. peroneus summoning f -response threshoLd (p<0.05). MacrovascuLar vioLations (PWV increase and EF decrease) more associated with nerves eLectricaL activity changes than microcircuLation impairment.

Keywords:digital capillaroscopy, stimulation electromyography, glycemic control

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