Plasma viscosity pattern and erythrocyte aggregation in two patients with congenital afibrinogenemia.

: In this case report, we examine the behavior of plasma viscosity, explored at high and low shear rates, and erythrocyte aggregation in two patients with congenital afibrinogenemia, a clinical disorder firstly described in 1920 and that has an estimated incidence of 1 : 1-200 0000. The two hemorheological parameters examined by us showed a marked decrease in both patients, in one of whom erythrocyte aggregation was even undetectable. Keeping in mind that spontaneous thrombosis (venous and arterial) has been often described in congenital afibrinogenemia, it can be hypothesized that the decrease in plasma viscosity and erythrocyte aggregation might cause a reduction of the endothelial synthesis and release of nitric oxide through the fall of the wall shear stress.