Influence of rheological parameters on the velocity of erythrocytes passing nailfold capillaries in humans
Issue title: Selected Presentations from the 29th Conference of the German Society for Clinical Hemorheolgy and Microcirculation, Freie Universität Berlin, Germany, 17–18 September 2010
Affiliations: Center for Biomaterial Development and Berlin-Brandenburg Center for Regenerative Therapies (BCRT), Helmholtz-Zentrum Geesthacht, Institute of Polymer Research, Teltow, Germany | Institute for Hemostasiology and Transfusion Medicine, University Saarland, Homburg/Saar, Germany | Central Institute for Biomedical Engineering, Department Biomaterials, University of Ulm, Ulm, Germany | Akademische Lehrpraxisklinik der Technischen Universität Dresden, Dresden, Germany
Note: [] Corresponding author: F. Jung, Center for Biomaterial Development and Berlin-Brandenburg Center for Regenerative Therapies (BCRT), Helmholtz-Zentrum Geesthacht, Institute of Polymer Research, 14513 Teltow, Germany. E-mail: [email protected]
Abstract: One thousand two hundred and fifty-six subjects (apparently healthy subjects and patients with cardiovascular diseases) were registered in a prospective study including demographical and clinical data, rheological parameters (hematocrit, plasma viscosity, erythrocyte aggregation, erythrocyte deformability) as well as the erythrocyte velocity in human nailfold capillaries under resting and postischemic conditions. A multivariate regression analysis showed that under resting conditions there was no correlation between rheological parameters and erythrocyte velocity in capillaries. The blood flow regulation seemed to be so effective, that pathological changes of the blood fluidity showed no effect on the velocity of an erythrocyte passing the capillaries. During vessel paralysis in the early phase of the postischemic hyperemia following a stasis of three minutes in the vasculature distal to a pressure cuff at the upper arm a very clear correlation between the plasma viscosity and the maximum postischemic erythrocyte velocity in ipsilateral cutaneous capillaries could be observed (p < 0.0001) while none of the other rheological parameters seemed to play a role. In a subgroup of diabetic patients the erythrocyte aggregation (measured during stasis) also correlated with the erythrocyte velocity (p = 0.0175) besides the plasma viscosity. This shows that a correlation of rheological parameters with the capillary perfusion could only be found during vessel paralysis. In of diabetic patients besides the plasma viscosity also the erythrocyte aggregation correlated with the mean capillary erythrocyte velocity. Theses results are in agreement with the hypothesis from Barras that plasma viscosity determines the perfusion of microvessels. Under certain conditions e.g. diabetic disorder, also the erythrocyte aggregation plays a role.
