Skin microcirculation in patients with arterial hypertension and in patients with a combination of arterial hypertension and type II diabetes mellitus

Abstract

Introduction . Common combination of arterial hypertension (AH) with type 2 diabetes mellitus (DM2) which has a negative impact on the incidence and prognosis of coronary artery disease (CAD) imposes a requirement to study their interdependent effects, primarily at the microcirculation (MC) level. Aim. To study peculiarities of functional state of skin MC in patients with a combination of AH and DM2 compared to patients with AH. Materials and methods . Two groups of patients were examined: group 1 (n=66) – patients with a combination of AH and DM2, and group 2 (n=93) – patients with AH. Skin MC was assessed by laser Doppler flowmetry. Basal blood flow, amplitude-frequency spectrum of its oscillations, occlusion indicators, and incidence of various hemodynamic MC types were assessed. Results . In patients with a combination of AH and DM2, progressive deterioration of MC indicators was detected, compared to patients with AH without DM2. Statistically significant differences were revealed in more pronounced tone of the precapillary segment of the microvascular bed (myogenic tone 60.5 [37.4; 83.6] vs 49.1 [31.3; 61.0] units; р=0.014). Impaired function of active blood flow control mechanisms with increase in the role of passive regulation factors was found, as evidenced by lower modulation index (1.3 units in group 1 vs 2.8 units in group 2). In patients with a combination of AH and DM2, there were detected the strengthening of arterio-venous shunts bypassing the capillary bed and blood flow productivity reduction (increase in indicator of bypass grafting up to 1.6 [1.0; 2.1] units) compared to patients with AH and without DM2 up to 1.2 [0.8; 1.5] units; р=0.037), limitation of vasodilation blood flow reserve which amounted to 173.4 % [135.3; 195.4] vs 184.9 % [166.1; 231.3] (р=0.025). Conclusion . More significant changes in microhemocirculation were registered in patients with a combination of AH and DM2 compared to patients with AH. It was characterized by constriction of the microvascular bed precapillary segment with restriction of capillary blood flow, strengthening of arterio-venous shunts bypassing with formation of venous congestion, and reduction of MC reserve potential.