Importance of blood viscoelasticity in arteriosclerosis

Corpuscular and biochemical components of blood create the viscoelastic nature of blood flow, which varies because of changes in flow velocity. The flow properties of blood are of special interest in arteriosclerotic diseases for vasoregulatory mechanisms are often disturbed in these states. The authors compared the rheologic properties of blood in patients with arteriosclerotic lesions (coronary heart disease: n = 56; cerebrovascular disease: n = 37; peripheral arterial occlusive disease: n = 29 and healthy controls: n = 42). With a new oscillating capillary rheometer imitating the physiologic pulsations of blood flow in an unbranched artery, the viscosity (eta') and elasticity (eta") of whole blood and plasma were measured (diameter of the capillary: 0.9928 mm; pulse rate: 2/s; shear rate: gamma = 0.03-200/s; temperature: 37 degrees C). In arteriosclerotic patients a statistically significant elevation of the viscoelasticity of whole blood and plasma was found. In addition, plasma fibrinogen levels were augmented in the patients' groups. Clotting parameters (Quick, partial thromboplastin time, platelet count) and total serum protein levels were in the normal range in all patients investigated. In conclusion the question arises whether the increase of blood viscoelasticity is an additional risk factor for patients with arteriosclerotic disease or if it is just a consequence of the underlying disease. The authors' observations concerning blood viscoelasticity support the clinical importance of improving blood rheology by appropriate therapeutic measures.