Blood Rheology Alterations in Patients with Cardiovascular Diseases.

Blood rheology is an important determinant of blood flow but is probably one of the most neglected areas in clinical literature and practice. Blood viscosity changes according to shear rates and depends on cellular and plasma factors. RBCs' aggregability and deformability are the main determinants of local flow characteristics in areas with lower and higher shear rates, but plasma viscosity is the main regulatory factor of flow resistance in the microcirculation. In individuals with altered blood rheology, the mechanical stress to vascular walls induces endothelial injury and vascular remodelling, and promotes atherosclerosis. Increased values of whole blood viscosity and plasma viscosity are correlated with cardiovascular risk factors and adverse cardiovascular events. The long-term effects of physical exercise can produce a hemorheological fitness that protects against cardiovascular diseases.