Haemorheological alterations in Behçet's disease are not related to a tendency for venous thrombosis

Introduction: Behçet's disease is associated with an increased risk of thrombosis, although the prothrombotic mechanisms are unclear. Alterations in blood rheology, particularly increased erythrocyte aggregation, might play a role in the development of such thrombotic events. Materials and methods: We measured plasma lipids, fibrinogen, haematocrit, erythrocyte aggregation, erythrocyte deformability, blood viscosity, plasma viscosity and erythrocyte indexes in patients with a nonactive disease at sampling, and in a well-matched control group. The patient group comprised 42 patients with BD (21 male, 21 female aged 43±12 years) and the control group comprised 46 healthy volunteers (23 male, 23 female aged 45±13 years). Twelve of the 42 patients with BD had a previous documented history of deep vein thrombosis at least 6 months before entering the study, and the other 30 did not. Results: Compared with controls, patients showed statistically higher fibrinogen concentrations (P=0.001), plasma viscosity (P=0.002), blood viscosity (P=0.006) and erythrocyte aggregation, both at stasis (P=0.001) and at a low shear rate (P=0.002): the other rheological parameters were not statistically significant. No differences were observed in the rheological parameters when patients with and without previous thrombotic episodes were compared. Conclusions: Although patients with BD show a moderate hyperviscosity syndrome, possibly related to chronic inflammation, this does not seem to play a role in the development of thrombotic events.