The role of blood viscosity in the development and progression of coronary artery disease

BACKGROUND: Although a great deal of attention has been directed to the risk factors for atherosclerotic coronary artery disease, relatively little research has been focused on the role of the circulating blood itself. OBJECTIVES: To review the possible role of increased plasma viscosity and decreased cellular deformability in the pathogenesis of atherosclerotic coronary artery disease. SUMMARY: Increased plasma viscosity or decreased erythrocyte deformability may reduce blood flow in areas where blood flow is already low, such as at arterial branch points and bifurcations as well as in advanced coronary artery narrowing. Further, these factors may favor the development and progression of atherosclerotic coronary artery disease through direct mechanical effects on either the vascular endothelium or existing atheromatous plaques. Beyond their potential direct effects, each may represent a common link between recognized risk factors and the resulting disease process. CONCLUSIONS: Accumulating evidence suggests that increased blood viscosity is an independent risk factor for atherosclerotic heart disease and its complications.