Hemorheological studies of chosen clinical cases

Abstract

Rheology – the study of the flow of matter and accompanying phenomena of real bodies deformation – in relation to blood – hemorheology. Blood viscosity – the main rheological parameter – has been studied in many research centers and among many different group of patients. The main disorders related to the hemorheological properties are: coronary insufficiency, vascular congestion, myocardial infarction, cerebral circulation disorder, Reynaud disease, ischemic limbs, diabetes, anemia, tumors. The following parameters are the main blood viscosity determinants: plasma viscosity, hematocrit, red cell deformability and erythrocytes aggregation. In hemorheological studies we used mathematical rheological models. The measurements of blood and plasma viscosity are performed by means of oscillating-rotary rheometers in order to determine the dependence of blood viscosity on the shear rate and the two components of the complex blood viscosity. Determination of blood cells aggregability and deformability is performed directly by means of aggregometers and appropiate filters and indirectly using rheological techniques with advanced mathematical models of blood viscoelasticity. Blood and plasma viscosity are subject to autoregulation mechanisms of the body. Recognition of those mechanisms may help in assessment of some diseases risk: ischemic stroke or myocardial infarction. In many cases rheological measurements may reveal the most recent phases of diseases and disorderses which enables early therapy with specimens improving the blood fluidity. For this reason rheological measurements should be applied in diagnostics and therapy. Mutual relations between the main factors determining the blood viscosity and their effect on blood flow are the main subject of current report.

Can Assessment of Rheological Properties of Whole Blood and Plasma Be Useful in the Diagnosis of Tinnitus? A Pilot Study

“…The large dispersion in the mean values of hemorheological parameters may be due to the relatively large variation due to comorbidities, where differences in hemorheological parameter values were also observed [34].…”

“…The value of the k 0 parameter changed from the minimum value of 3.05 to the maximum one equal to 4.36, the k ∞ parameter shifted from 1.48 to 1.90, and particularly high discrepancies were observed in the case of the γ c parameter changing from 1.53 to 15.16. In fact, the γ c parameter represents the moment of formation of red blood cell packets (rouleaux formation) [33,34,39,40]. The decreased whole-blood viscosity in the low shear rate range, i.e., in the range where aggregation is the dominant process [13][14][15], may imply the significance of this process in the studied patient group.…”

“…The present study analysed the results of blood rheological properties in patients complaining of tinnitus, as well as presenting other vascular, or metabolic diseases (Table 3). Whole blood viscosity, plasma viscosity, the tendency of erythrocytes to aggregate, and deformation depends not only on the type and duration of the disease, but also on comorbidities and administered medications [13,15,30,34,41].…”

“…Statistically significant differences were observed in the values of hemorheological parameters in the selected neurological diseases, both in relation to the control group and partially between patient groups. Therefore, the application of hemorheological tests in the diagnostic process of tinnitus may contribute to a better diagnosis and may be effective for further therapy [15,34].…”

Interdependence of Rheological and Biochemical Parameters of Blood in a Group of Patients with Clinically Silent Multifocal Vascular Cerebral Lesions

“…Blood was collected in Vacutest ® tubes (4 mL, with K 3 EDTA). The time from collection to measurement did not exceed four hours to avoid the necessity of any special treatment of blood samples [22]. All viscosity measurements were performed using a rotary-oscillating rheometer Contraves LS40 (Zurich, Switzerland) at 37 • C. The measurement system used is the Couette DIN 412 system, whose geometric parameters according to the specification are: internal radius (Ri) 6 mm; external radius (Ra) 6.5 mm; length of the contact surface of the sample (L) 18 mm; and volume of the sample, 1.8 mL.…”