Microcirculation and blood rheology abnormalities in chronic heart failure.

BACKGROUND: Generalized restricted blood flow is hallmark of CHF of any etiology, but the extent of microcirculation restriction and the role of intrinsic blood properties in heart failure remains unknown. OBJECTIVE: The aim of this study was to estimate the microvascular blood flow and hemorheological properties in chronic heart failure to test the hypothesis that CHF patients have altered peripheral blood flow which contributes to the tissue perfusion disturbances. METHODS: Cutaneous microvascular blood flow was estimated by Laser Doppler and Optical Tissue Oximetry techniques. Whole blood and plasma viscosity were measured by capillary viscometer, red blood cell aggregation was evaluated by direct microscopic method, erythrocyte deformability was assessed as elongation index in flow microchamber. Hematocrit-to-viscosity ratio was used as index of oxygen transport efficacy. RESULTS: Depression of the regulatory mechanisms of microvascular blood flow as well as decreased tissue perfusion indicated the restricted blood flow in microcirculatory network in CHF. Increased blood and plasma viscosity, enhanced red blood cell aggregation and decreased erythrocyte deformability were registered in CHF. CONCLUSIONS: Complex impairment of peripheral blood flow in CHF including restricted microcirculation, attenuated regulatory mechanisms and impaired hemorheological properties caused the reduced oxygen utilization contributing to symptoms and advance of heart failure.

Interrelation of blood coagulation and hemorheology in cancer.

Cancer progression is associated with activation of blood coagulation. Blood coagulation process, platelet hemostasis and hemorheological properties were evaluated in patients with solid tumors (n = 27) before and after surgery and in healthy control (n = 20). The main features of blood coagulation process in cancer patients were elevated intensity and shortened period of contact phase of coagulation and inhibited fibrinolysis stage. Such prothrombotic state was fixed before surgery as well as in early postoperative period in spite of preventing thromboprophylactic treatment. Platelets depletion within the high level of spontaneous and ADP-induced platelet aggregation was fixed in cancer. The main cause of blood viscosity decrease in cancer patients was dramatic fall of Hct, because blood viscosity adjusted by Hct 40% was increased owing to the rise of plasma viscosity and substantially worsened RBC microrheological properties. The results of our study indicated close correlation between hemorheological and hemostasis parameters; these interrelations were more numerous and strong in cancer. In cancer patients the combination of a high aggregation activity of platelets, reduced number of erythrocytes (Hct), an increase of RBC aggregation and plasma viscosity caused impairment of blood oxygen transportation efficacy that provoke hypoxia in the microcirculation favoring thrombosis, settlement of tumor and metastasis.