Changed blood rheology in patients with idiopathic dilated cardiomyopathy.

Rheologic properties of blood were studied in 8 patients with dilated cardiomyopathy (DCM) and in 10 healthy subjects. Whole-blood viscosity was measured at four different shear rates, by means of a computer-controlled rotational viscometer. The patients had significantly higher blood viscosity at all shear rates, both at their natural hematocrits and after an in vitro adjustment of sample hematocrits to 45%. Erythrocyte filterability (5 microns pore size) was significantly lower, fibrinogen concentration significantly higher, and HDL-cholesterol concentration significantly lower in the patient group. No significant differences were found regarding hematocrit, mean corpuscular volume, hemoglobin concentration, leukocyte count and filterability (8 microns pore size), plasma viscosity, and total cholesterol concentration. The measured hemorheologic abnormalities may contribute to the previously reported reduction of coronary blood flow reserve in DCM patients and to myocardial microcirculatory disturbances, which have been suggested as a cause for DCM.