Interrelations of Hemorheological Parameters and Microcirculation in Subjects with an Increased Blood Pressure

Abstract

Vascular resistance and blood pressure (BP) have known effects on blood viscosity. Therefore, the purpose of this study was to investigate the interrelation between the set of rheological characteristics and the parameters of microcirculation in patients with moderately increased blood pressure. We measured the hemorheological characteristics, including blood viscosity (BV) at high and low shear rates, plasma viscosity (PV), the viscosity of erythrocyte suspension, hematocrit (Hct), and erythrocyte aggregation and deformability. We also evaluated the efficacy of the transport function of blood. We determined the functional capillary density (FCD) using the method of microscopy and recorded the value of microvascular perfusion in patients with elevated blood pressure (mean blood pressure above 97 mmHg) and a group of subjects with normal blood pressure (control group, mean blood pressure of 87 mmHg) using laser Doppler imaging (LDI). We studied the changes in microrheological characteristics of red blood cells during their incubation in the presence of compounds with vasoactive properties: spermine (a donor of nitric oxide), ADP, and adenosine. Subjects with high blood pressure had a higher BP than the controls. This was due to an increase in PV, Hct, and erythrocyte aggregation with a decrease in their deformability. The ATP content of red blood cells was measured in patients with elevated blood pressure; it was found to be lower by 25% (p < 0.01) than in the control group. It was found that the content of ATP in erythrocytes was significantly negatively correlated with the values of blood pressure (systolic and diastolic blood pressures); the correlation was stronger in patients with a high blood pressure. These findings suggest that the characteristics of the hemorheological profile and the parameters of microcirculation in patients with moderately elevated blood pressure were significantly different from those in subjects with normal blood pressure. This indicates a reduction of the effectiveness of microvascular tissue perfusion.